CSE_20_10 by Modiconlv

the ART of Building Sustainability

HVAC

SECURE DATA

INTEGRATED FAULT DETECTION & DIAGNOSTICS

OWNERSHIP OF ANALYTICS

SINGLE-APP EXPERIENCE

Lighting

CERTIFIED OPEN STANDARDS

Ensure a strong level of interoperability by using open protocols which have third-party listing laboratories to verify adherence to your protocol’s form and function.

B UIL

LIT Y

ART o

S U S TA I N

Employ a single sign on (SSO) architecture with compliance to scalable credentialing architectures and secure tunneling methodologies such as BACnet virtual private networks (B/VPN).

Select lifecycle-centric manufacturers who minimize the negative impacts of waste with long-term warranty and repair services while adhering to WEEE, RoHS and LEED directives.

Specify integrated FDD (IFDD) that delivers real-time fault detection, step-by-step root-cause diagnostics while using all your existing cabling structures, including twisted-pair networks.

Enjoy the long-term benefits of suppliers who engineer a path forward to new technologies while remaining backwards compatible without third-party gateways or hardware replacement.

Insist on timely analytics for all stakeholders with complete control of formatting and scheduling while retaining full ownership of your data and the reports generated.

Stay on top of regular advances in technology with supplier-certified, multi-lingual online educational videos, technical documentation, software updates, and advanced face-to-face classroom courses.

Create better-connected spaces with real-time access to occupancy, lighting, ventilation, and thermal comfort levels, using a holistic single app on the occupant’s mobile device.

Choose from a global network of factory-certified service partners who are passionate about long term, consistent, local support for you and your buildings.

Security

MINIMAL WASTE

BACKWARD COMPATIBLE

OPERATOR TRAINING

FACTORYCERTIFIED SERVICE

Sustainability requires a high level of integration between HVAC, lighting, and security systems. The art of building sustainability skillfully combines this integration with other technological and supporting elements that must endure over the long term. When these additional elements are maintained over the life of your building, true building sustainability emerges. To learn more about the ART of Building Sustainability please visit reliablecontrols.com /TABS10CSE19

input #1 at www.csemag.com/information

Vol. 57, Number 9

OCTOBER 2020

BUILDING SOLUTIONS 20 | Navigating hospital ventilation design during COVID-19

COVID-19 has impacted ventilation design considerations in health care settings in a prominent way

25 | Sustaining indoor air quality

ON THE COVER: In this Las Vegas resort property, one of the main unit substation electrical rooms is shown. Courtesy: Bear Label Consulting Engineers

NEWS &BUSINESS 3 | Viewpoint

Can engineers save the world?

Maintaining IAQ is imperative for occupant health and comfort as well as the reliable operation and longevity of information technology equipment

29 | How virtual design, artificial intelligence impact engineers

Architecture, engineering and construction professionals will be impacted by virtual design and artificial intelligence tools

4 | 2020 Commissioning Giants

35 | How virtual design changes the way we work

6 | Commissioning Guideline offers best practices, approaches

40 | How operational understanding leads to resilient design

The 2020 Commissioning Giants data reports on the top 25 firms

ACG’s reimagined document recognizes new priorities now that commissioning is business as usual

BUILDING SOLUTIONS 10 | Back to basics: Commercial building wiring methods

Electrical engineers and designers should have a practical understanding for the application of raceways, wiring, cabling and busways

16 | Making IAQ better with COVID-19 in the air

How can building HVAC systems be modified to provide a safer environment in new and renovated spaces?

Virtual design is an option for coordinating building plans virtually

Designing a resilient building requires understanding of both the built environment and operations

44 | Harnessing an interdisciplinary team for resilient design By collaborating with an interdisciplinary team, engineers can offer high-value, holistic solutions that promote resilient design

ENGINEERING INSIGHTS 49 | Students, tech, COVID drive higher ed design

College and university building design is being driven by student needs, technology and new air quality demands

CONSULTING-SPECIFYING ENGINEER (ISSN 0892-5046, Vol. 57, No. 9, GST #123397457) is published 11x per year, monthly except in February, by CFE Media and Technology, LLC, 3010 Highland Parkway, Suite #325 Downers Grove, IL 60515. Jim Langhenry, Group Publisher/Co-Founder; Steve Rourke CEO/COO/Co-Founder. CONSULTING-SPECIFYING ENGINEER copyright 2020 by CFE Media and Technology, LLC. All rights reserved. CONSULTING-SPECIFYING ENGINEER is a registered trademark of CFE Media and Technology, LLC used under license. Periodicals postage paid at Downers Grove, IL 60515 and additional mailing offices. Circulation records are maintained at CFE Media and Technology, LLC, 3010 Highland Parkway, Suite #325 Downers Grove, IL 60515. Telephone: 630-571-4070. E-mail: cse@omeda.com. Postmaster: send address changes to CONSULTING-SPECIFYING ENGINEER, PO Box 348, Lincolnshire, IL 60069. Publications Mail Agreement No. 40685520. Return undeliverable Canadian addresses to: , PO Box 348, Lincolnshire, IL 60069. Email: cse@omeda.com. Rates for nonqualified subscriptions, including all issues: USA, $165/yr; Canada/Mexico, $200/yr (includes 7% GST, GST#123397457); International air delivery $350/yr. Except for special issues where price changes are indicated, single copies are available for $30 US and $35 foreign. Please address all subscription mail to CONSULTING-SPECIFYING ENGINEER, PO Box 348, Lincolnshire, IL 60069. Printed in the USA. CFE Media and Technology, LLC does not assume and hereby disclaims any liability to any person for any loss or damage caused by errors or omissions in the material contained herein, regardless of whether such errors result from negligence, accident or any other cause whatsoever.

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October 2020

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www.csemag.com

NEWS&BUSINESS VIEWPOINT

CONTENT SPECIALISTS/EDITORIAL AMARA ROZGUS, Editor-in-Chief/Content Strategy Leader ARozgus@CFEMedia.com AMANDA PELLICCIONE, Director of Research APelliccione@CFEMedia.com MICHAEL SMITH, Creative Director MSmith@CFEmedia.com CHRIS VAVRA, Associate Editor CVavra@CFEMedia.com

EDITORIAL ADVISORY BOARD JERRY BAUERS, PE, Vice President, NV5, Kansas City, Mo. MICHAEL CHOW, PE, CEM, CxA, LEED AP BD+C, Principal, Metro CD Engineering LLC, Columbus, Ohio TOM DIVINE, PE, Senior Electrical Engineer, Johnston, LLC, Houston CORY DUGGIN, PE, LEED AP BD+C, BEMP, Energy Modeling Wizard, TLC Engineering Solutions, Brentwood, Tenn. ROBERT J. GARRA JR., PE, CDT, Vice President, Electrical Engineer, CannonDesign, Grand Island, N.Y. JASON GERKE, PE, LEED AP BD+C, Cx A, Mechanical Engineer, GRAEF, Milwaukee JOSHUA D. GREENE, PE, Associate Principal, Simpson Gumpertz & Heger, Waltham, Mass. RAYMOND GRILL, PE, FSFPE, Principal, Arup, Washington, D.C. DANNA JENSEN, PE, LEED AP BD+C, Principal, Certus, Carrollton, Texas WILLIAM KOFFEL, PE, FSFPE, President, Koffel Associates Inc., Columbia, Md. WILLIAM KOSIK, PE, CEM, LEED AP BD+C, BEMP, Senior Energy Engineer, Oak Park Ill. KENNETH KUTSMEDA, PE, LEED AP, Engineering Manager, Jacobs, Philadelphia SARA LAPPANO, PE, LC, LEED AP, Managing Principal, Integral Group, Washington, D.C. JULIANNE LAUE, PE, LEED AP BD+C, BEMP, Director of Building Performance, Mortenson, Minneapolis DAVID LOWREY, Chief Fire Marshal, Boulder (Colo.) Fire Rescue JASON MAJERUS, PE, CEM, LEED AP, Principal, DLR Group, Cleveland BRIAN MARTIN, PE, Senior Electrical Technologist, Jacobs, Portland, Ore. DWAYNE G. MILLER, PE, RCDD, AEE CPQ, CEO and Co-Founder, UNIFI Labs Inc., Las Vegas GREGORY QUINN, PE, NCEES, LEED AP, Principal, Health Care Market Leader, Affiliated Engineers Inc., Madison, Wis. BRIAN A. RENER, PE, LEED AP, Principal, Electrical Discipline Leader, SmithGroup, Chicago SUNONDO ROY, PE, LEED AP BD+C, Vice President, CCJM Engineers Ltd., Chicago JONATHAN SAJDAK, PE, Associate/Fire Protection Engineer, Page, Houston RANDY SCHRECENGOST, PE, CEM, Austin Operations Group Manager/Senior Mechanical Engineer, Stanley Consultants, Austin, Texas MATT SHORT, PE, Project Manager/Mechanical Engineer, Smith Seckman Reid, Houston SAAHIL TUMBER, PE, HBDP, LEED AP, Senior Associate, Environmental Systems Design, Chicago MARIO VECCHIARELLO, PE, CEM, GBE, Senior Vice President, CDM Smith Inc., Boston RICHARD VEDVIK, PE, Senior Electrical Engineer and Acoustics Engineer, IMEG Corp., Rock Island, Ill. MIKE WALTERS, PE, LEED AP, Campus Energy Market Leader, MEP Associates, a Salas O’Brien Company, Verona, Wis.

Can engineers save the world? The COVID-19 pandemic has pushed engineers to improve indoor air quality

ost of the news over the buildings and students. We won’t know past six months has cen- the results of all of these efforts until tered on one thing: the many years from now. COVID-19 pandemIt remains a fact that, unless you live ic. And, as much as the public wants in a tropical country and don’t require a new story to follow, the coronavirus any type of conditioned air, humans has remained on a low, rolling boil ever have to go into buildings. Whether it’s since it hit the United States. a home or multifamily dwellOther hot topics have ing, a school or a workplace, popped up to challenge — or a hospital or a manufacand even dominate — the turing facility, the buildnews cycle for one or even ing needs to be prepared for several days. Right now, polhumans. itics and the election cycle Consulting engineering tend to take over reports of firms, much like doctors and overworked doctors or vachospitals treating COVID-19 Amara Rozgus, cine trials. But it’s nearly patients, are often asked for Editor-in-Chief impossible to get away from the answers on how to keep the thing that consumes us: buildings safe. What types of COVID-19. ventilation will be best for reducing the The pandemic is an international spread of the virus? Are there disinfecproblem. It’s being tackled from various tion systems for both surfaces and air? angles on the medical front. Reports How does an engineer design a smart abound about a vaccination on the edge building so that its occupants have both of being ready, or about countries vacci- knowledge about and control over their nating their essential workers, or a drug surroundings? that seems to cure the virus’s ills. According to Consulting-Specifying The medical and research commu- Engineer research released in July, 65% nities have been racing to help in any of respondents indicated that project way possible. Social media groups have demand for maintenance, repair and given doctors a forum to share best operation would increase. And 59% practices. Pharmaceutical companies said that retrofit/renovation projects have pledged to “stand with science,” would increase as a result of COVIDand place research and clinical trials 19. That meshes with anecdotal reports ahead of any external pressure. Diag- I’ve received about engineers being nostic companies and state departments extremely busy updating, upgrading of public health are pushing the limits and reconfiguring buildings in prepaof what they can do with virus testing. ration for U.S. residents spending more But as of this moment, there don’t time indoors during the winter. seem to be any easy answers. People are While not all of these answers are still dying. Virus rates are going up in available, some of the questions of some places and down in others. Some indoor air quality are considered in countries are barring international visi- a series of articles about ventilation, tors. Educators are wringing their hands codes and standards and air quality in over making the right choice for school general. cse

APRIL WOODS, PE, LEED AP BD+C, Vice President, WSP USA, Orlando, Fla. JOHN YOON, PE, LEED AP ID+C, www.csemag.com Lead Electrical Engineer, McGuire Engineers Inc., Chicago

consulting-specifying engineer

October 2020

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SPECIAL REPORT By Amara Rozgus, Editor-in-Chief

Commissioning Giants The 2020 Commissioning Giants data reports on the top 25 firms

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For the 2020 Commissioning Giants report, the top 25 companies made $536 million in revenue, a slight dip from last year’s $551 million.

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he 2020 Commissioning Giants reports the top 25 firms based on whether the company chose to be considered in this year’s rankings. The average percentage of commissioning revenue earned by the 2020 Commissioning Giants was approximately 31%, showing that these top 25 firms earn a great deal of their revenue from commissioning, with two firms earning 100% of their revenue solely from commissioning. See Table 1 for the complete ranking, including the four new companies. For the 2020 report, the top 25 companies made $536 million in revenue, a slight dip from last year’s $551 million. The majority (44%) of firms are consulting-engineering firms with a commissioning division; about a quarter (24%) are commissioning-focused firms. Firm ownership type fell into four categories: private (36%), public (28%), employeeowned (24%) and limited liability company (12%). The average commissioning fee per project varied. Forty-four percent of companies earned $100,001 to $300,000, 28% earned $25,001 to $50,000 and 20% earned $50,001 to $100,000. Only 8% earned more than $300,000 per project. This data reflects commissioning at all levels: new buildings (43%), existing buildings (12%), retro-commissioning (11%), whole building (10%), emergency power systems (6%), building enclosure (envelope, 5%), recommissioning (5%), monitoring-based (4%), fire protection systems (3%) and communications systems (2%). Each reporting firm completed, on average, 251 commissioning projects (at any level) in 2019, up from 239 in last year’s report. The top three building types commissioned by these firms: • Data centers: 20%.

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October 2020

consulting-specifying engineer

• Hospitals/health care facilities: 20%. • Colleges/universities: 10%. According to survey respondents, these firms were contracted to complete commissioning for a variety of reasons: mandates (codes, standards, benchmarking: 92%), savings (energy efficiency, lower life cycle cost: 92%) and sustainability (long-term materials and performance efficiency: 92%.) Other reasons included resiliency (68%) and marketability of the property (44%).

Commissioning challenges

The 2020 Commissioning Giants study asked for information related directly to challenges for these firms. The top three current challenges for the 2020 Commissioning Giants are: • Staffing: quality of young commissioning professionals (36%). • Staffing: keeping older commissioning professionals trained/current (16%). • The economy’s impact on the construction market (12%).

Future challenges varied. The No. 1 challenge was the “lack of knowledge about commissioning’s worth,” with 60% respondents saying it was a problem (an uptick from 48% last year). The next challenge, at 48%, was “lack of funding or buy-in (from owners, engineers, etc.) to conduct commissioning.” Moving into third place this year at 44% was “not enough commissioning authorities or agents or commissioning professionals.” This surpassed “codes and standards changing,” which came in at 28% this year, an increase from 20% in the previous report. cse www.csemag.com

Commissioning firm types Engineering/architectural; architectural/ engineering firm

Other

20%

Figure 1: The majority of firms are consultingengineering firms with a division committed to commissioning at various levels. Courtesy: Consulting-Specifying Engineer

44%

12% 24%

Commissioning, balancing, etc. only

Consulting engineering firm

Table 1: 2020 Commissioning Giants Firm name

Total commissioning revenue for fiscal year

Jacobs

$191,070,000

Bureau Veritas Primary Integration

$43,000,000

2020 Rank

2019 Rank

IPS-Integrated Project Services

$30,589,785

Hood Patterson & Dewar

$30,110,000

Facility Dynamics Engineering

$29,557,242

McKinstry

$28,600,000

WSP USA

$15,500,000

Horizon Engineering Associates

$15,251,000

SSRCx

$14,567,729

NV5 Global Inc.

$14,212,429

Engineering Economics Inc.

$12,400,000

AECOM

$11,000,000

Burns & McDonnell

$10,393,355

CBRE

$9,567,865

Affiliated Engineers Inc.

$9,449,194

RMF Engineering Inc.

$9,400,000

The High Performance Buildings Group (Glumac, NDY, Cosentini)

$9,381,559

Critical Solutions Group

$9,100,000

CMTA Inc.

$7,688,112

Sindoni Consulting & Management Services Inc.

$7,140,808

Morrison Hershfield

$6,408,791

Jaros, Baum & Bolles

$5,637,550

Bernhard

$5,500,000

EYP Mission Critical Facilities Inc.

$5,428,800

Heapy

$5,298,171

Table 1: The top 25 firms earned $536 million in the past fiscal year. All firms reported having a commissioning engineer or coordinator on staff and 96% indicated they had a business development director. Courtesy: Consulting-Specifying Engineer www.csemag.com

consulting-specifying engineer

October 2020

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SPECIAL REPORT By The AABC Commissioning Group (ACG)

Commissioning Guideline offers best practices, approaches ACG’s reimagined document recognizes new priorities now that commissioning is business as usual

he ACG Commissioning Guideline, first published by AABC in 2002 and updated and published as the 2nd Edition by AABC Commissioning Group in 2005, has long been recognized as a resource that explains the commissioning process properly and concisely. The two previous editions of the guideline addressed commissioning primarily within the context of heating, ventilation and air conditioning systems because they were written by industry professionals experienced predominantly in the testing of these systems. However, the publication’s crisp presentation of commissioning process elements, stepby-step approach and roles and responsibilities kept it relevant even as the scope of commissioning grew over the past 15 years to encompass many additional building systems. With the publication of the industry’s first consensus-based ANSI commissioning standard — ASHRAE Standard 202 – 2018: Commissioning Process for Buildings and Systems (which ACG supported) — the commissioning industry now has a common, continually maintained benchmark for the minimum requirements for building commissioning as a professional service. ACG Building Systems Commissioning Guideline under development is responding to these broad changes by shifting the focus of the guideline to presenting best practice narratives for executing the process. These practical guides

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October 2020

will offer insight and strategies from experienced providers on a variety of topics, designed to help providers get commissioning done in the real world — effectively and efficiently — while overcoming common challenges. Guideline sections will cover topics including system-specific commissioning guidance, approaches for accomplishing key commissioning goals, managing processes, directing resources and producing valuable commissioning deliverables. To take one example: the ASHRAE Standard 202 requires that commissioning meetings take place, while the ACG Building Systems Commissioning Guideline explains what meetings to organize and when, who should lead and participate in them and what tools will help in scheduling, facilitating and documenting meeting activities. The following is the first in a series of “sneak previews” of the guideline, in this case, a description of building enclosure commissioning by Brian Marsh, PE, Smith Seckman Reid Inc., Nashville.

Commissioning building enclosure systems

The building enclosure commissioning process delivers quality assurance measures to ensure the owner’s project requirements are achieved for systems that provide environmental separation between the outdoor and indoor environments. Building enclosure commissioning is an integral part of the total or whole building commissioning process as the building enclosure not only serves

consulting-specifying engineer

to shelter occupants from the elements, but also protects the many other commissioned systems and services critical to a building’s operation. Enclosure systems carefully designed and constructed with attention to durability and serviceability support a building’s mechanical systems to promote healthy interior environments for the life of the facility. A successful BECx process can effectively help facility owners receive buildings that have been verified to meet an expected level of performance and promote solutions that mitigate risks of air and water leakage, as well as poor thermal and vapor control that commonly result in issues such as condensation, corrosion, decay, biological growth, occupant discomfort and increased energy consumption. Systems commissioned in the BECx process typically include all interconnected assemblies, components and materials forming the six-sided building enclosure, with careful consideration of detailing at complex and challenging interfaces and transitions between systems. The process can be tailored to specific owner and project needs to focus on select systems of concern or be expanded to include all systems that create environmental separation. Building enclosure systems and components routinely commissioned include the following: • Waterproofing. • Roofing. • Air barrier. • Moisture barrier. www.csemag.com

• Vapor barrier. • Cladding. • Fenestrations. • Glazing. • Insulation. • Sealants.

Figure 1: Water intrusion damage is shown in a K-12 school auditorium. Courtesy: Facility Commission Group

Other notable systems that are often considered for inclusion in the BECx process when applicable and vital to the project include the following: • Dynamic/automated systems (e.g., sunshades, electrochromic glazing). • Partitions surrounding spaces with tightly controlled or extreme interior conditions (e.g., cleanrooms, ice rinks, biosafety laboratories). • Interior waterproofing of wet areas (e.g., showers, pools, wet treatment rooms). The owner and the building enclosure commissioning provider should identify not only the systems to be commissioned, but also the performance characteristics of each system that have the most influence on the owner’s and project’s goals established in the OPR. Water, air, vapor and thermal control normally top the list of performance characteristics most critical to the performance of the building enclosure. Performance characteristics defined in the OPR and basis of design can define requirements for control of or resistance to, the following: • Water leakage. • Air leakage. • Vapor diffusion. • Thermal flows. • Condensation. • Fire. • Ultraviolet radiation. • Infrared radiation. • Light transmittance. • Acoustics. • Environmental contaminants. • Insects/vermin. • Forced entry. • Blast pressures. • Relative building pressures. While building enclosure commissioning is rooted in the same core fundamentals and objectives as the commissioning of other building systems, the focus and approach are tailored to the unique challenges inherent to building enclosure syswww.csemag.com

tems. Enclosure failures and performance deficiencies typically occur at interfaces and transitions between components and systems and at conditions involving multiple trades. BECx reviews place a greater importance on how the properties and performance of individual assemblies and materials will interact and interface when multiple trades assemble them in the field to perform as a single, coordinated system. Additionally, opaque wall assembly primary water, air, vapor and thermal control layers and their associated transitions, are usually concealed from view once the building is completed. As such, the BECxP must devote careful attention to the design of these systems and thoughtfully coordinate the timing of site observations during the course of construction to help ensure a successful outcome.

Design phase

From project inception to construction, the design team establishes myriad assumptions about the building envelope that have significant implications on the simulated and as-built whole building performance. Early in design, initial energy models are developed using assumptions of air leakage rates, levels of insulation, cladding attachment, thermal bridging and glazing system performance. The mechanical engineer uses enclosure airtightness assumptions to determine volumes of outside air needed to maintain building pressurization and calculate external loads to size mechanical equipment. The BECxP should be capable of identifying and evaluating these assumptions as designs are being developed to ensure they are reasonable and attuned to the vision established in the OPR. The BECx process should support the project team in advancing these

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assumptions from concepts to operational reality. The commissioning process is most effective when the commissioning provider is an independent third-party contracted to the owner. While the BECxP does not design building enclosure systems or components as part of the commissioning process, reviewers must be able to objectively evaluate the architect’s accuracy and effectiveness in translating the owner’s enclosure requirements into the technical requirements conveyed to the contractor in the construction documents. The BECxP’s team should include individuals that specialize in the design and commissioning of building enclosures and oftentimes include multiple individuals that subspecialize in specific building enclosure systems such as waterproofing, roofing and curtain walls. These individuals should bring considerable technical expertise and experience in building enclosure systems that can enhance and expand the project team’s abilities. The design team often calls on the BECxP to provide technical support to facilitate resolution to challenges such as control layer discontinuity at system transitions with complex geometry, material

consulting-specifying engineer

October 2020

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SPECIAL REPORT compatibility concerns and component layer sequencing and constructability challenges. However, sole responsibility for designing a fully functional building enclosure must remain with the architect/ engineer of record.

Construction phase

Buildings are uniquely designed and constructed using a variety of materials and systems in numerous configurations. Given the realities of design schedules and budgets, fully detailed design documents are seldom achieved before the start of construction. If projects only used proprietary closed specifications, the design team could develop project-specific details for contractors to imitate for every unique transition and condition to be encountered on the building given generous time and resources. For the vast majority of projects using open specifications, the final coordination of detailed design is carried forward with construction coordination documents — product submittals and shop drawings — that demonstrate the contractor’s understanding of the design intent using the specific products and systems being supplied to the project. Where many building systems commissioning providers review submittals and shop drawings for commissionability only, BECx reviews also consider product selections and detailing with regard to control layer continuity, durability, serviceability, constructability and coordination between trades at transitions and interfaces between systems. To facilitate this collaboration and coordination between trades, the BECxP will often participate in pre-construction or pre-installation meetings. In addition to the challenges created by design complexities encountered when joining materials and systems in multiple configurations, the interfaces and transitions between systems are constructed by teams of trade contractors and tradespeople unique to each project. The opportunity for a test-run of building enclosure construction in the form of a mock-up can provide numerous benefits to the project team by further facilitating and fostering trade collaboration and coordination. A carefully thought-out mock-up program should incorporate enclosure systems

• October 2020

Figure 2: A typical blower door assembly is applied during a building air leakage functional performance test. Courtesy: Facility Commission Group

and details that the project team deems crucial to project success. A standalone, off-building, laboratory or site-built mockup constructed before the start of building construction allows the project team to make observation, perform tests and provide acceptance to demonstrate that the designed systems can and will, be installed to collectively function to meet the OPR. Many critical enclosure systems — especially opaque wall systems — are fully site-fabricated and installed using multiple materials and layers that provide unique functions. Oftentimes, building enclosure primary control layers (e.g., air barriers, thermal insulation, water-resistive barriers) and their transitions to other systems are concealed with subsequent layers and cladding when complete. The layered nature of wall assemblies necessitates periodic BECx site visits that are thoughtfully and diligently coordinated to occur during the early or first installation of a critical component in order to observe and document enclosure construction. When the BECxP is not on-site, building enclosure installation checklists can be a useful tool to emphasize to contractors the important systems or material requirements and to document that contractors are providing some level of quality control. However, the level of workmanship conveyed is highly dependent on the training and judgment of the individual completing the check-

consulting-specifying engineer

list. Building enclosure checklist completion can also be challenging to manage because the systems reviewed do not include discrete pieces of equipment with defined startup periods and the critical components are concealed when systems are put into service. Issues noted in site observation or on testing reports are logged into an issues and resolutions log as the party largely responsible for trade coordination, the general contractor is usually best suited to respond to enclosure system issues on the BECx issues and resolutions log. Photographic documentation of repairs can often serve to resolve outstanding issues without delaying construction progress while the project team waits for BECxP on-site verification before concealment. Verification testing, such as fenestration air and water leakage testing, is preferably performed throughout the course of enclosure construction when critical control layers are easily accessible. Problems discovered during final verification testing and acceptance just before occupancy can be daunting and costly to diagnose and resolve; therefore, greater emphasis is typically placed on tests performed during the course of construction.

Occupancy phase

Given that the building enclosure is largely comprised of static systems that do not require extensive operational knowledge to function, operations and maintenance phase activities are primarily focused on resolving new or ongoing issues during occupancy and training facility operations staff to understand the maintenance schedules and techniques required to ensure ongoing system performance. The post-occupancy site visit provides a valuable opportunity to interview facility personnel about ongoing issues and review maintenance requirements. Building enclosure commissioning summary reports that provide illustrations of multilayered assemblies with descriptions of the function of each component can educate facility personnel on the consequences for lack of maintenance or alterations to the in-service building. cse

By The AABC Commissioning Group (ACG) www.csemag.com

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CONSULTING-SPECIFYING ENGINEER

October 2020

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BUILDING SOLUTIONS

WIRING, CABLING AND BUSWAYS By Clinton R. Gordon, LEED AP; and Matthew Steinmetz, PE, Bear Label Consulting Engineers, Las Vegas

Back to basics: Commercial building wiring methods Electrical engineers and designers should have a practical understanding for the application of raceways, wiring, cabling and busways

lectrical engineers and designers have different methods of serving loads within a building when it comes to the use of wiring, cabling and busway. The decision to specify one method over another or a combination of multiple methods can be driven by many factors including local jurisdictional requirements, new construction versus remodel, project cost, owner preference or standards, building height and/or type and future goals for the building. In selecting various wiring, cabling or busway systems, the engineer or designer is typically faced with compromises in functionality, future flex• Review the different types ibility and first cost, all of which of raceway and conductor should be considered before proceedmethods. ing with the specifications for the proj• Understand the differences ect installation. The “when,” “where” with manufactured cabling and “why” for applying certain wirassemblies. ing, cabling and busway methods is • Learn about the application of based on the 2017 edition of NFPA 70: busways and bus ducts. National Electrical Code.

Learning

OBJECTIVES

Raceway and conductor methods

NFPA 70: National Electrical Code Chapter 3 covers several wiring methods, and this article will focus mainly on commercial construction applications of 600 volts or less. NEC Article 300 - General Requirements for Wiring Methods and Materials applies to all wiring installations unless modified by other articles in Chapter 3. NEC 300 covers requirements such as protection against physical damage, minimum cover for underground installations, securing and supporting, mechanical/electrical continuity and where boxes, conduit bodies or fittings are required. NEC Article 310 - Conductors for General Wiring applies to the individual conductors used in the

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October 2020

consulting-specifying engineer

specified wiring methods and the requirements for their designations, insulation, marking, ampacity and allowable uses. Note that Articles 300 and 310 do not apply to integral or internal parts of listed equipment. The raceway and conductor method consists of metallic or nonmetallic conduit or tubing with multiple insulated phase, neutral and possibly an equipment ground conductor depending on the applicable method and NEC requirements. Each raceway and conductor installation is field fabricated based on the design plans and specifications. Most consultants typically specify conductors of the type THHN/THWN (thermoplastic high heat-resistant nylon jacket/thermoplastic heat and water-resistant nylon jacket) or XHHW (XLPE high heat-resistant and water-resistant) in copper or aluminum for these applications. Copper typically is specified for branch circuits and either copper or aluminum is specified for feeders. Some of the common types of raceways used in commercial applications include: • Intermediate metal conduit (type IMC) per NEC 342. IMC is a thin-wall version of RMC with a galvanized exterior and an interior corrosion resistant coating. It is typically specified as a lower-cost solution to RMC where it offers the same levels of protection. • Rigid metal conduit (type RMC) per NEC 344. RMC (also known as RGS or GRC) is a thick wall galvanized steel conduit with a zinc coating on the exterior and interior of the raceway. RMC is typically specified where the maximum protection is required from physical damage. www.csemag.com

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In selecting various wiring, cabling or busway systems, the engineer or designer is typically faced with compromises in functionality, future flexibility and first cost.

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• Flexible metal conduit (type FMC) per NEC 348. FMC (also called greenfield) is a conduit available in multiple types of metal and wall thicknesses. It’s typically specified for the final connections to motors, transformers or other vibrating or moving equipment. • Liquidtight flexible metal conduit (type LFMC) per NEC 350. LFMC is a conduit similar to FMC, but with a polyvinyl chloride jacket. LFMC is typically specified for final connections to equipment in damp or wet locations. • Rigid polyvinyl chloride conduit (type PVC) per NEC 352. PVC conduit is available in multiple types but most commonly specified as either Schedule 40 or Schedule 80, referencing the wall thickness. It generally is specified for underground applications directly buried or concrete encased and can also be used in some corrosive environment applications. Because this raceway is nonmetallic, it does not offer any grounding capabilities.

Figure 1: In this resort property on the Las Vegas strip, one of the main unit substation electrical rooms is shown. The electrical room contains medium-voltage feeds with step-down transformers within the unit substation for low-voltage distribution to this part of the building. Courtesy: Bear Label Consulting Engineers Figure 2: Overhead electrical metallic tubing raceways are installed in the back-of-house corridor. Courtesy: Bear Label Consulting Engineers

• Electrical metallic tubing (type EMT) per NEC 358. EMT is by far the most common raceway in commercial construction. EMT is a threadless thin-wall steel tubing with a galvanized exterior and a corrosion-resistant interior coating, which is also an aid in pulling conductors. It should be noted that cable trays as covered in Article NEC 392 are not raceways. Cable trays are a structural system used to mechanically support and manage cables. For reference, the NEC uses two terms regarding protection but the NEC does not define the terms “physical damage” or “severe physical damage,”, which is left to the authority having jurisdiction’s discretion. Physical damage might be limited to forcible human contact with tools or equipment whereas severe physical damage would entail mechanized or vehicular contact. The physical location of the installation will also factor into the determination. www.csemag.com

Advantages to raceways, conductors: • Once installed, changes in circuit configuration are possible to an extent depending on the raceway type and size, such as changes in conductor size or conductor quantity. • Types IMC or RMC can be installed in locations subject to severe physical damage. consulting-specifying engineer

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WIRING, CABLING AND BUSWAYS • Type PVC is listed as sunlight resistant and can be used exposed outdoors, however be aware that “resistant” does not mean sunproof. Some environments will degrade the life of the PVC conduit where exposed to severe sun and heat. If the temperature variance exceeds 25°F expansion joints will be necessary. In extreme cold environments, PVC conduit will become very brittle.

Figure 3: Metal-clad cable feeders are installed to serve branch circuit panelboards in a high-rise building. Courtesy: Bear Label Consulting Engineers

• Type EMT can be installed in locations subject to physical damage. • Types IMC, RMC, LFMC or EMT can be installed in dry, damp or wet locations (note NEC 358.10 for EMT was updated for 2017 with additional permitted uses). • Raceways can be used more easily during remodel work by allowing the conductors to be changed out or within multitenant spaces and shell buildings where landlords provide raceways for tenants’ future use. • Exposed installations of EMT, IMC or RMC are more appealing where craftsmanship is shown. • Raceways can be abandoned where the conductors are removed from the installation. • Underground installations with PVC are inexpensive and very common Disadvantages of raceways, conductors: • Installed costs are usually more expensive due to labor needed for initial raceway installation and then return labor to install conductors. • Limited in the number of bends before a junction box or pull-box is required. • Some types of conduit cannot be installed in locations subject to physical damage such as FMC, LFMC or PVC. • Type PVC cannot be used for health care applications with patient care.

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• Type PVC is combustible and cannot be installed within a return air plenum found in Type I and II buildings as defined by the International Building Code for building construction types. • Type PVC limits the installed conductor’s insulation temperature rating to that of the listing of the PVC conduit. Adjust the rated operating ampacity of the conductor accordingly. • RMC and IMC typically use threaded connectors and elbows, which are more costly and time-consuming to install. RMC and IMC can be field threaded and bent with specialized tools and equipment. • Requires more thought and coordination during installation versus cabling systems due to more rigid routing requirements. • Engineer or designer is required to spend more thought/time on raceway sizing and potential derate impacts due to current carrying conductor quantities in a raceway versus a pre-manufactured cabling system.

Manufactured cable assembly methods

As mentioned above, NEC Articles 300 and 310 also apply to manufactured cable assemblies. Manufactured cable assemblies consist of multiple insulated phase and neutral conductors with an insulated and/or bare equipment grounding conductor(s) wrapped and enclosed within either a metallic or nonmetallic sheath. Manufactured cable assemblies are available as standard product offerings from the manufacturer or as custom assemblies with specified conductor configurations, which may come with extended lead times and minimum order lengths. Consultants will find that these cable assemblies generally come standard with THHN/THWN or XHHW-2 (copper or aluminum) conductors in most cases. Some of the common types of manufactured cable assemblies used in commercial applications include: www.csemag.com

How to know when busways are the right choice

ome applications for busway or bus duct include building operation. One example of such a risk is relatinstallation within a high-rise building with vertied to a bus duct installation within a high-rise tower cally routed bus duct. This high-rise building could serving multiple floors. be a mixed-use occupancy, office building or a residenVertical bus duct was used and installed within the tial building. The consultant should consider the feeder hotel tower and ran vertically within electrical closbus duct routed from the main switchboard to the core ets on each floor. The bus duct was installed without a area of the high-rise building. The bus duct would tran- surrounding floor curb and waterproofing as currentsition to the vertical routing within the core area of the ly required by NEC 368.10(C)(2). A service sink within high-rise building. the core building housekeeping Each floor of the buildcloset on one of the floors was Like any electrical distribuing would contain an electrical left on and overflowed. Water tion system, there can be room stacked for the bus duct. ran down the corridor and The vertical bus duct would be found its way into the electrical inherent risks to the system the plug-in style bus duct with closet and over to the bus duct. based on installation or plug-in modules and overcurWater proceeded to run vertibuilding operation. rent protective devices for the cally down the bus duct, causelectrical distribution equiping a fuse to short and started ment serving the specific floor. A few more applicaa fire. This short took down the vertical bus duct and tions for busways could be installations for industrial/ the entire tower for more than 24 hours. process manufacturing, big box retail spaces, convenAll of the guests were forced to evacuate and had tion centers or even within a data center with horito make other accommodations for their stay. Though zontally routed busway. The horizontal busway is this may not be common, this is a risk that vertical bus connected to a feeder from the power distribution ducts can pose, which wouldn’t have existed to the equipment serving the area. The horizontal busway same extent with a cabling or raceway system. That is with plug-in modules would be located overhead in the not to say bus duct shouldn’t have been specified, but area where load changes could be frequent. proper installation methods and operational proceLike any electrical distribution system, there can be dures should have been followed and the possible risks inherent risks to the system based on installation or to an outage could have been reduced.

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• Armored cable (type AC) per NEC 320. AC is a set of conductors assembled within a metallic sheath of either steel or aluminum armor where the sheath is also used as a ground path. It typically is specified for branch circuit connections between luminaires and power receptacles. • Metal-clad cable (type MC) per NEC 330 is one of the more commonly used cable types in commercial construction. MC cable is a set of conductors assembled within a metallic sheath of either steel or aluminum interlocking armor where the sheath is not used as a ground path. MC cable is also available with an outer PVC jacket for wet locations or direct burial. It’s usually specified for branch circuit connections between luminaires and power receptacles, and also is common for distribution feeders to branch circuit panelboards. • Mineral-insulated, metal-sheathed cable (type MI) per NEC 332. MI cable is generally used for specialized applications such as compliance with NEC 700 emergency systems. MI cable is a seamless copper sheath containing copper conductors within a magnesium oxide insulation. www.csemag.com

• Nonmetallic sheathed cable (types NM, NMC, NMS) per NEC 334. NM cable (also called Romex) is a set of conductors assembled within a nonmetallic sheath with PVC insulation and a nylon jacket, usually with a bare copper grounding conductor. This is generally used for lighting, switches and receptacle branch circuits in light commercial and residential construction. • Service-entrance cable (types SE, USE) per NEC 338. SE cable is a set of conductors assembled within a nonmetallic sheath with cable reinforcement and an outer PVC jacket. Generally, it’s used for service drops to a meter pedestal or as a distribution feeder to a branch circuit panelboard. • Underground feeder and branch-circuit cable (type UF). UF cable is a set of conductors assembled within a nonmetallic sheath with PVC insulation and a nylon jacket contained within a gray PVC outer jacket. UF is generally used for outdoor direct burial feeders and branch circuits to detached garages and lighting fixtures. consulting-specifying engineer

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WIRING, CABLING AND BUSWAYS Advantages to cable assemblies: • Installed cost generally lower, mainly due to labor not needed twice to install conduit and then wire. • Install time is faster due to less labor and more flexibility on cable routing with the exception being MI cable, which requires special installation methods.

• Not limited in the number of bends during installation. • Factory-tested assembly. • Types AC and MC can be used where flexibility is necessary for equipment connections. • Type MI cable is fire resistant (a special type MC cable is also available that is fire resistant). • Type MI cable is typically installed in free air, which allows higher ampacity ratings with equally sized conductor compared to other types (verify with the manufacturer’s listing and ratings). • Type NM cable is likely the most inexpensive method available (verify with the local jurisdiction for the application as some AHJs do not allow this method along with types SE and UF). Disadvantages of cable assemblies: • Securing and supporting required at a shorter spacing. • Once installed, changes in circuit configuration are not possible. • Cannot be installed where subject to physical damage.

Figure 4: This bus duct application serves a high-rise building (typical upper floors for a vertical bus duct riser). Courtesy: Bear Label Consulting Engineers

• Types AC or MC cable must be installed in dry locations (unless provided with a listed jacket). • A special type AC or MC cable is required for health care applications with patient care (verify with the local jurisdiction as some AHJs do not allow AC or MC for patient care areas). • Exposed installations are not appealing although when installed in cable trays it is beneficial. • Some jurisdictions will not allow cable assemblies to be abandoned within building construction.

Figure 5: This shows typical electrical metallic tubing homerun for branch circuits into a space to serve metal-clad cable to lighting fixtures and power receptacles. Courtesy: Bear Label Consulting Engineers

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• Type NM cable is limited by building type and occupancy (and is generally regarded as a residential or light commercial installation). • Types NM, SE and UF are combustible; note some jurisdictions will not accept their use. www.csemag.com

• Contractor is required to have on hand or order for the exact circuit configuration for use on a project. Alternatively, common raceway and conductor sizes can be on hand and used in multiple configurations providing greater application flexibility. • Parallel sets and transformer secondaries require yet another cable type to be ordered or on hand due to larger ground size requirements. • More planning required during cabling procurement.

Busway methods

Another type of wiring method includes a busway, which is sometimes called bus duct. By definition, a busway is a metal enclosed raceway with factory-mounted busbars. All types of busways fall under the scope of NEC Article 368, which includes service-entrance, feeder and branch-circuit busways. Generally, busway comes in either feeder style or plug-in style configurations with either insulated or bare conductors. Advantages to busways: • More compact in physical size than multiple conduits for the same ampacity feeder. • Available in many ampere ratings from 60 to 4,000 amps. • Plug-in style busway offers flexibility to add and change load takeoffs. • Total voltage drop with bus duct application is less impactful. Be aware of extremely long runs of feeder bus duct where one is looking to maintain 2% voltage drop. Disadvantages of busways: • Installed cost potentially higher, especially if many elbows and offsets are needed. • Susceptible to failure due to water leaks within the building (note some jurisdictions require sprinkler-proof plug-in busway, which has an ingress protection rating of IP54). • Cannot be installed where subject to severe physical damage. • The available short-circuit current on the bus duct could be very high. Be aware of the short-circuit current rating when using plugin circuit breaker modules.

Figure 6: Metal-clad cable branch circuits serve a cookline in a kitchen. Note that equipment changes in the future may be limited based on the circuiting provided within the cable assembly. Courtesy: Bear Label Consulting Engineers

• 100% rated circuit breaker plug-in modules may be not available. • Limited space for bus plugs in vertical applications depending on equipment room layout and position of bus duct. These wiring methods are only a part of all the potential listed methods available on the market for use on a project. Although these are the wiring methods you will most likely encounter on a commercial project, be aware that due to other circumstances another wiring method may be more applicable. Always check the code and with your AHJ for the “uses permitted” and “uses not permitted” for each wiring method application. cse Clinton R. Gordon is a project executive with Bear Label Consulting Engineers. His project experience spans nearly 30 years and includes electrical systems design and project management for hotel and casino resorts, high-rise buildings, office complexes and restaurant and retail venues. Matthew Steinmetz is principal, CEO, mechanical and electrical engineer with Bear Label Consulting Engineers. For more than 16 years, he has completed multidiscipline engineering on large and midscale project types including integrated resorts, gaming, hospitality, hotel, high-rise, retail, restaurant, office and health care.

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Read more online at www.csemag.com about: • Designing with raceways consulting-specifying engineer

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CODES AND STANDARDS

By Sunondo Roy, PE, LEED AP, CCJM Engineers Ltd., Chicago

Making IAQ better with COVID-19 in the air How can building HVAC systems be modified to provide a safer environment in new and renovated spaces?

ndoor air quality has always been an engineering concern for building owners and managers and heating, ventilation and air conditioning designers and engineers. Engineering challenges are already omnipresent from ensuring adequate ventilation is maintained for maximum occupant comfort and productivity to avoiding the myriad complications from sick building syndrome and microbial contamination at the air handling units. The current COVID-19 pandemic has put a new twist to the already multifaceted design challenges. Up to now, most HVAC contamination concerns • Understand how the COVID-19 have been located in a known locavirus spreads through the air in tion (e.g., outside air intakes, mold or buildings. other microbial growth in coil drain • Learn about airflow issues, and pans and drift carry-over into the ducwhat mechanical engineers need twork) or a high concentration, like to consider in occupied spaces. carbon dioxide, in the indoor ambient • Review how ventilation and air that is not being effectively diluted. environmental standards

Learning

OBJECTIVES

(ASHRAE Standard 62.1 and 55, respectively) will be affected by the spread of the COVID-19 virus.

Airflow issues

The problem with COVID-19 and ventilation is counterintuitive. With most inactive airborne contaminants like volatile organic compounds and carbon dioxide, we achieve an acceptable level of dilution to maintain an acceptable threshold limit for these common contaminants through prescribed quantity of outside air in the supply air based on occupancy or over time. Generally, higher than code ventilation and overall airflow rates flush out contaminants in the occupied space more efficiently, though at greater energy usage versus code ventilation rates. For biological contaminants, specialized HVAC systems and room arrangements, e.g., positive and negative pressure isolation rooms, direct airflow from clean to contaminated and exhausted without recirculation in the space. The relative location of the patient and health care workers determine whether it’s an

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isolation or protection room. Most HVAC engineers understand this well. The challenges with COVID-19 are twofold. First, aerosolized COVID-19 generally behaves like other airborne contaminants and tends to diffuse within a space and moves with air drafts. Unlike inactive contaminants however, repeated doses of exhalated virus being circulated throughout the space on drafts can infect people far away from the source. Although greater ventilation and airflow will dilute the concentration, they also increase recirculation of the virus in the breathing zone through drafts. Second, unlike the negative or positive pressure isolation room described above, large numbers of unidentified, infected persons moving about freely in an enclosed space poses an immensely greater design challenge. Instead, we now have public spaces like office buildings, retail outlets, schools, restaurants and other public buildings that were never designed to control the person-to-person spread of respiratory virus laden air in the same space. Additionally, the COVID-19 infected person is typically moving about freely within the public space. That makes the engineered removal of the airborne virus contaminants virtually impossible. To make matters even more complicated, the current research indicates there is a significant risk of spreading the disease through aerosolized virus particles which remain suspended in the occupied space. Within all enclosed spaces, the first line of defense against the spread of the virus is wearing a face mask according to public health agencies like the Centers for Disease Control and Prevention and World Health Organization. Whether layered cloth, surgical or N95, masks specifically limit the spread of exhaled respiratory virus particles in droplets and even aerosol form. If a mask can significantly limit the release of the virus into the ambient conditioned air with negligible viral load, then there is very little concern the HVAC system will spread the airborne www.csemag.com

virus particles past the masks to adjacent or nearby people. Although this concept has been communicated clearly by health experts, there has been resistance due to external social factors that are causing a significant portion of the population from regularly wearing a mask in public. This is unfortunately causing the infection rate to explode across the country. Thus, we are back to engineers trying to come up with work arounds in public spaces. Due to the variability of space layout and relatively high occupant density of conventional office spaces, the risk of spreading the infection can be very high. A problem with the majority of conventional office HVAC design and construction is that it assumes the only contaminants in offices are benign gases and particulates that can freely mix throughout the space and be diluted safely through a thorough mixing of the ambient air and fresh air in the breathing zone. The more the ambient air is mixed and replaced, the better the IAQ is assumed to be. Engineers aspire to design and have installed HVAC systems with no stagnant air pockets and a uniform temperature distribution. To achieve that, engineers depend on traditional overhead office HVAC to take advantage of the coanda effect to have supply air hug the ceiling and gradually diffuse and drop as the airflow velocity drops to where the effect no longer exceeds the gravity effect on the colder, denser air and it drops to the occupied zone and offsets the heat sources of the space. In perimeter zones, the distribution gets trickier due to the need to push air down along the perimeter fenestration and “curl” back up along the interior. That circular pattern is the start of problems in the post COVID-19 world. Conventional air movement in commercial office spaces with lay-in ceilings tends to travel horizontally along the ceiling and then slowly drops down (see Figure 1). This airflow pattern minimizes the likelihood of spreading contaminated air from one person to adjacent people as the majority of the horizontal movement is well above the breathing zone. Air movement in the breathing zone is typically very low velocity-induced air combining primary conditioned air with ambient room air. Increasing www.csemag.com

Figure 1: This shows varying air movement patterns in confined spaces from an overhead supply air diffuser discharging cooling and heating air. The primary air movement and secondary eddy currents need to be modeled or observed with smoke tests to understand how suspended particles move within the space. Diagrams are adapted from ASHRAE Fundamentals Handbook, 1993, Chapter 31. Courtesy: CCJM Engineers Ltd.

air changes would reduce the virus concentration in the space, but that increased airflow, if not accounted for with proper diffuser/neck size selection, also has the potential to spread the virus if drafts intersect and primary airflow in the breathing zone becomes more horizontal than vertical. Some recent ASHRAE COVID-19 guidance has suggested increasing the outside air percentage through the air handling system. It is true that greater supply air to the space will dilute the concentration of airborne viral aerosol and droplet nuclei in the space. However, unless research and testing can prove aerosols and droplet nuclei are being drawn back to the AHU and recirculating back into the space, increasing outside air percentage through the AHU will not dilute the virus in the conditioned airstream because the AHU system itself is not the source of the contaminant. Unlike CO2 from occupant breathing, which can be easily measured in the return airstream to prove it is reintroduced to the occupied space if not diluted with outside air, it is not a given that high viral load infectious aerosols and droplets are being entrained in the return air stream and recirculated back through the HVAC system as live virus in concentrations to cause likely infection. Because the contaminant source doesn’t originate in the HVAC system like mold or Legionella and it isn’t suspected to be drawn back to the AHU as live virus in any significant quantity, it isn’t likely to be distributed through supply ductwork. The droplets are too heavy to get drawn up into the return ducts and the aerosols are getting diffused and precipitating in the occupied space, or at most precipitating in return air plenums and ductwork, if they even make consulting-specifying engineer

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Due to the variability of space layout and relatively high occupant density of conventional office spaces, the risk of spreading the infection can be very high.

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Figure 2: In an open office, high supply, low return/exhaust is used to minimize mixing in the breathing zone. This approach reduces horizontal drafts that push exhaled air across the occupied space and other workers to return grilles that are typically biased toward building cores in open offices and corners of confined rooms. Courtesy: CCJM Engineers Ltd.

it up that high. Any larger aerosol that may get to the AHU will likely attach to wet coils and filter media. There needs to be much more research on how many live virus particles make it into the return ducts and then through cooling and heating coils, filters, etc. Unlike molds and other fungi that can go dormant and spread spores that can propagate once conditions are suitable months or years after, dead viruses remain so and are of no concern. If the presence of live virus in the HVAC system is high and sustained, even the regular removal of filters and equipment maintenance will require significant service technician personal protective equipment and proper disposal. To minimize the spread of the COVID-19 virus in a mechanically ventilated space, the air distribution has to be more like an isolation room with only one pass across the breathing zone. Because we don’t know who’s infected, there’s no practical place to return the air like at the head of the patient bed in an isolation room. In light of that, one approach is to setup an inverted underfloor displacement ventilation system. In a conventional underfloor displacement ventilation system, supply is released down low (typically floor diffusers) in the occupied zone and returned up high where the hot air is out of the occupied zone. With COVID-19, the optimal system has air dropping straight down at low velocity to minimize blow-

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ing respiratory droplets and aerosols horizontally toward adjacent people and complementing gravity to draw down contaminated air toward the floor and eliminating aerosols from being drawn back up through the breathing zone (see Figure 2). This is an expensive solution in new or totally renovated spaces and the height of the raised floor needs to minimized to allow short ramps or other adjustments to account for the change in floor height. Alternately, the return air can be routed through floor openings to the ceiling cavity below and ducted back to return air shafts. This is a relatively easy solution that only shifts the return air to the floor below, but otherwise doesn’t drastically change the building air handling system. Either approach does require significant buyin and coordination with architects and building managers. However, this approach does significantly reduce the likelihood of cross-contamination of clean supply air and contaminated breathing air in the occupied zone. An alternate approach for existing spaces that still minimizes cross-contamination is to put return air chases in walls and partitions with return air slots near floor level.

ASHRAE 62.1 and 55

Whenever discussions revolve around airflow and ventilation, ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality and ASHRAE 55: Thermal Environmental Conditions for Human Occupancy always should be reviewed for their relevance to the discussions. Both of these standards have a direct interaction with regard to the factors controlling the dilution of the virus in the occupied space and how the air distribution in the space affects inadvertent spread of the virus from one person to others around them. www.csemag.com

Looking at ASHRAE 62.1 first, it is useful to review the intended purpose and scope of the standard relative to the spread of an infectious respiratory virus. Section 2 describes the scope of the standard and states in subsection 2.6, “Ventilation requirements of this standard are based on chemical, physical, and biological contaminants that can affect IAQ.” Pertinent to the current situation, subsection 2.8 states, “This standard contains requirements in addition to ventilation, related to certain sources, including outdoor air, construction processes, moisture and biological growth.” The standard defines IAQ as, “air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.” Reviewing these passages, the standard clearly has jurisdiction of specialized conditions to mitigate the spread of COVID-19 virus within buildings based on the stated purpose and subsection 2.6 of the scope of the standard. Knowing the lethality of the COVID-19 virus and the anonymous spread of the virus through regular respiration, all air within each occupied space appears to now fall under the most severe classification, Class 4, which is defined as “Air with highly objectionable fumes or gases or with potentially dangerous particles, bioaerosols or gases, at concentrations high enough to be harmful.” There may be some argument that the passage about “… concentrations high enough to be harmful …” may not apply to this situation. Some may even try to argue that this does not apply to an office environment where generally sedentary activity may not create an environment where enough viral load is being exhaled in such force as to spread the droplets or aerosol beyond an individual’s personal space. However, because the prevalence of asymptomatic, infected and contagious persons is being reported in the news media to be very high, the only defensible design assumption has to be that building spaces must be treated as if all occupants are COVID-19 positive. If designers accept that all indoor air in occupied spaces is now to be treated as Class 4, that changes the fundamental operations of all buildings. The majority of commercial building AHUs do not have the cooling and heating capacity to be converted to 100% outdoor air units. Compounding this dilemma, even if designers can convert all systems to 100% outside air with direct exhaust from each space, it still does not, on its own, address the spread of the virus from personto-person within a given space. Yes, there is dilution of the viral load with a space, but doesn’t the movement of air within the space itself cause the spread of the virus? Additionally, it is not certain or even likely that the virus in concentrations that will make a differwww.csemag.com

ence, returns to the AHU and then gets recirculated back to the occupied space. If it isn’t proven that the virus successfully recirculates, there’s little benefit in the energy penalty of 100% outside air units or even higher than current minimum ventilation rates in ASHRAE 62.1-2019, Table 6.2.2.1, Minimum Ventilation Rates in Breathing Zone. In the only space a similar situation previously existed, hospital isolation rooms, the air distribution system is specifically designed to minimize the spread of the infections exhalation of a known infected person by drawing clean, outside air across the room, washing health care workers with clean air as it is drawn to the infected patient and exhausted as close to the patient’s head as practical. In the new normal of COVID-19, the infectious patient is anonymous, mobile and numerous. Beyond wearing masks to minimize the spread of the virus at the source, it does not seem there is any simple, quick and cheap solution. At a minimum, personal desk fans that can blow ambient air from one cubicle to another should be categorically removed. As suggested above, the inverted displacement ventilation model with return/exhaust down low at floor level, though not cheap, does provide a credible means of minimizing the spread of the virus. The addresses some of the basic design concerns and solutions in new and renovated spaces as well as a brief review of how ASHRAE 62.1 may be affected by the pandemic as it currently spreads unchecked in many parts of the U.S. One of the most effective solutions is ultimately the simplest — wearing a mask. Although a vaccine may offer some relief to the COVID-19 pandemic, the global spread of the virus to every corner of the planet occupied by humans will ensure mutations with similar lethality will certainly evolve and the cycle will begin again. Where previous respiratory diseases like SARS and MERS were manageably confined to a region without global spread, it is likely that mutations of the current COVID-19 virus, which has established a foothold on every continent except Antarctica, will now spread much more readily across the globe. The much feared normal of global viral pandemics may be upon us. It is another health care and engineering challenge along with climate change. cse

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Looking at ASHRAE 62.1 first, it is useful to review the intended purpose and scope of the standard relative to the spread of an infectious respiratory virus.

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Sunondo Roy is a vice president at CCJM Engineers Ltd. He is a member of the Consulting-Specifying Engineer editorial advisory board.

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Ready more online at www.csemag.com about: • Particulate spread. • Technology solutions. • Site-specific applications. consulting-specifying engineer

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CODES AND STANDARDS

By April Woods, PE, LEED AP BD+C, WSP USA, Orlando, Fla.

Navigating hospital ventilation design during COVID-19 COVID-19 has impacted ventilation design considerations in health care settings in a prominent way

n early 2020, the novel coronavirus SARSCoV-2, also known as COVID-19, caught the world by surprise. As a society, the virus will have lasting impacts among most aspects of life, and it will certainly change the landscape of design in perhaps a permanent way. Not only will the design concepts in most public and commercial spaces be reconsidered, but this pandemic will be on the forefront of building owners’ minds as they progress through hospital designs in the future. Regardless of the length of time that this virus continues to impact our communities, it will not be quickly • Understand the role standards committees have forgotten and will have long-lasting had throughout the crisis in effects on design considerations in developing standards and best the future. practices.

Learning

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• Learn about the mechanical concepts the design community has considered to help prevent infectious disease spread.

Standards review, implementation

As engineers across the country started quickly responding to the disaster, it was evident that no singular design standard or code adequately guided the design community. Realizing the deficiency, many organizations such as the Centers for Disease Control and Prevention, the American Society for Healthcare Engineering, and ASHRAE banded together to develop some loose guidance that could be used specifically in the health care setting. Engineers, hospital owners, and health care experts all over the U.S. quickly formed focus groups to identify design strategies that could both be implemented for not only the influx of the surge of COVID-19 patients, but also permanent concepts that could be executed for pandemic scenarios

• Review the implementation of a mechanical ventilation strategy for a patient tower currently undergoing construction to respond to the influx of COVID19 patients.

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in the future. As more information has been realized regarding the virus, these recommendations have continued to evolve and will eventually lead to changes in future publications and addenda in current standards. To help assist with advancing the current standards to include guidance around the design and installation of heating, ventilation and air conditioning systems, ASHRAE created an epidemic task force and position documents to address the challenges of the current pandemic as it relates to the disease transmission in multiple public and private environments, including in health care facilities. One of the prominent ASHRAE standards that is used for most health care projects, ASHRAE Standard 170: Ventilation of Health Care Facilities, is continuing to be evaluated by the committee for formal guidance and possible revisions to include provisions required for pandemic solutions. As these recommendations were continually being clarified, the ASHRAE website was updated to keep the design community abreast with the most up-todate information. Other resources such as webinars and local chapter presentations have also proved to be useful for distribution of recommendations. At this time, it is unknown when permanent standards will be written or enforced. The current effort of the epidemic task force is focused on building readiness to allow for reopening of buildings in general, and not code-required specifics yet for modifications to permanently installed ventilation systems in health care facilities. Many of the schematics demonstrated throughout this article are based on previous recommendations for highly infectious disease units per the CDC and other notable resources, as well as requirements as enforced by the local authorities having jurisdiction. www.csemag.com

COVID-19 ventilation concepts

Although there are several unique design considerations that need to be considered in relation to the COVID-19 crisis, most notably and impactful to the HVAC world is the need for negatively pressurized spaces and careful consideration to airflow relationships with adjoining spaces and departments. This requires special consideration with regards to the ventilation system. While the term “ventilation air” can suggest many meanings, the ASHRAE Fundamentals 2017 defines it simply as “air used to provide acceptable indoor air quality.” Ventilation is the primary strategy in limiting the spread of infectious diseases through an air system and includes an array of control mechanisms including dilution, filtration, source capture and exhaust components. These functions can occur either at the base air handling unit system or at the room itself and carry a varying weight of effectiveness and cost. While there are many strategies that can mitigate the transmission of disease, arguably the most effective as it relates to the transfer within the HVAC system is intercepting the return air and diverting it to the exterior to prevent recirculation of the virus back throughout the hospital air system. This captures the contaminated air at the source and eliminates the ability for infected air to find its way back into the spaces and potentially infect other patients or staff. However, this solution may not be as feasible depending on the system configuration and the ease of routing exhaust ductwork to the exterior. This is especially true in retrofit applications where air systems were designed in a traditional manner that did not include diverting return air paths. Depending on the complexity of the air distribution systems and physical location of the source equipment, this strategy can become a burdensome and costly solution.

Easing the surge

Many of the early concepts that were created at the start of the COVID-19 crisis included simplistic temporary solutions to help assist during the surge, but were not meant for permanent applications. This included creating temporary negative pressure rooms from existing patient rooms using direct exhaust through high-efficiency particulate air filtration or installing temporary ante rooms at each patient room to create a sealed air barrier. In both applications, the return air grille is sealed to eliminate air transfer back to the main air handling unit and the HEPA filtered negative air machines creates the pressure relationship required to reduce contaminant spread. Pressure monitors, via digital or mechanical means, are provided to ensure continuous monitoring occurs and that the correct pressure relationship is maintained. While these solutions allow for temporary conversion of

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Figure 1: This exterior rendering of the Parkview Regional Medical Center Core Tower expansion project showcases the horizontal expansion and connection back into the existing main tower. Courtesy: HKS Inc. Architects

the spaces during surge applications, they are not suitable or practical for long-term operations of ongoing or recurrent pandemics. If possible, operating the AHUs that serve the pandemic area in 100% outside air with full exhaust is the most preferred method, although careful consideration should be taken before activating this sequence to ensure that the AHUs, coils, humidifiers and associated outside air ductwork and louver sections have been sized appropriately based on the seasonal duration of use. Potentially lowering the leaving supply water temperature at the chilled water plant can be investigated if capacity at the coils are deficient. Individual spaces would still need to be balanced to ensure that negative pressure relationships are maintained, but this strategy does ensure that contaminated air is not reentrained back into clean spaces. Additional protection either in the AHU or in the ductwork of HEPA filtration, use of ultravioletC lights, and/or ionic purification strategies could all be implemented in any of these strategies; however, the most effective strategy remains removal of the contaminated air from the spaces in conjunction with providing negative pressure spaces.

Permanent pandemic solutions

While these temporary conversion concepts of existing areas into intensive care units has been required to quickly adapt to the surge capacity needs, many hospital owners have seized the moment during existing construction projects to make crucial modifications to the mechanical systems to allow for conversion to fully negative pressure wings or suites. While each design solution is unique to the complexities of the individual project, the most overwhelmingly effective strategy is to divert the airstream to be a fully exhausted sysconsulting-specifying engineer

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tem. By carefully sequencing motorized dampers at strategic locations within the system, the dampers can be automated to divert the return airstream to be fully exhausted so no air from the contaminated area returns to the AHU. This allows the AHU to operate in a more traditional mode during nonpandemic operation and reduce the additional energy penalties. If the air was designed to be permanently exhausted rather than returned to the AHU, the additional outside air would be required during all hours of the year, resulting in significantly higher energy costs. Still, in this strategy, careful consideration needs to be taken to ensure that the outside air is properly balanced to make up for the additional exhaust that is removed from the building to maintain an overall positively pressurized building during pandemic mode. This increase of outside air could have impact on the overall size of the cooling coils, preheating coils and humidifiers within the central AHU system and the central energy plant that should be considered and evaluated. In addition, individual space pressurization needs to be assessed. While the motorized dampers will allow for an entire area or floor to become negative if additional air is removed above the existing return airflow values, the energizing of the exhaust

fan and damper control will not alone create negative rooms without another means of rebalance at the space level. This rebalance can be accomplished either through a manual rebalance of each space or through the activation of independent air valves provided on the supply and return systems. The air valves can be programmed with two distinct airflow setpoints: one for normal mode of operation and one for the pandemic mode and would operate in conjunction with the motorized dampers. While changing the pressurization from positive/ neutral to negative pressure at the space level can be a challenge, perhaps one of the most debated topics is the quantity of airflow that is required to be delivered and exhausted from the space. To modify a room from an ICU airflow to meet that of an airborne infection isolation room requires an increased airflow and total air quantity required to meet that of an airborne infection isolation room above a medical/surgical patient room is even higher. Refer to Table 1 for typical patient room type comparisons. Depending on the type of pandemic, a patient room designed as a true airborne infection isolation room may not be required. As with COVID19, which the main route of transmission is through respiratory droplets, the additional air change rate to turn over the air in the space may not be needed.

CASE STUDY: Hospital pivots to adjust for COVID-19

Included within the mechanical design are two large s COVID-19 began to loom in early spring 2020, the executive team at Parkview Health in Fort air handling unit systems, enclosed within a penthouse. Wayne, Ind., quickly started to evaluate how to General and isolation exhaust systems stack throughhandle both the upcoming surge while also preparing out the tower to carry exhaust to discharge at the extefor more permanent solutions systemwide. An active rior. These air systems distribute to multiple floors, which construction project on the Parkview Regional Medi- lends itself to an efficient design, with equipment housed cal Center campus was midconstruction, and includ- in one location and built in redundancies in all the equipment. It also allows for the ed a horizontal patient tower floor plates to be maximized expansion that was a prime This negative pressure relafor patient care and all precandidate for consideration. ventive maintenance to occur This new 165,000-squaretionship is achieved through an on the top floor. foot expansion project will airflow offset between supply When evaluating the house 72 new patient beds needs of the facility to idenwith the ability to further air and exhaust air, similar to an tify the most optimal location expand to 143 total beds. to isolate COVID-19 patients, Included within the project is airborne isolation room. it was determined that the a patient tower finish-out of top floor would be the most the top floors, with the bottom three floors being shelled. The new tower is con- appropriate choice. Although all of the overhead sysnected to a 900,000-square-foot existing tower that tems were nearly complete, the design and construction was completed in 2012. Design started on the Core team worked swiftly to evaluate how to accommodate Tower expansion project in 2018 and included a phased the future floor to be adjusted to function either as a turnover per floor with the first phase, the top floor — normal med/surg patient floor or as a COVID-19 unit. Although it was a complicated endeavor, the existing Level 06 — which opened in September 2020.

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Per the World Health Organization, these droplets are heavy enough that they cannot travel or linger in the air as long as other airborne viruses, such as the measles. Therefore, providing protection in a room with 12 air changes per hour of exhaust volume is not the governing factor and instead, the pressure relationship becomes the key driver to minimizing virus transmission in adjacent spaces. Airflow patterns as they relate to the patient and caregiver relationship should be considered to limit the spread within the space as well. To maintain a negative pressure relationship, either a reduction in the supply air or an increase in the return/exhaust airflow is required to achieve negative pressurization. The approach to simply change the airflow and not necessarily increase total airflow to the requirements of 12 ACH of exhaust was evident in the beginning of the COVID-19 crisis, as most authorities having jurisdiction would accept air balance modifications as necessary to become negative pressure, rather than enforcing a higher air change rate. This greatly reduced the burden on existing infrastructure systems that were already in operation or in construction to become more reasonably modified. However, total ACH is continuing to be evaluated by the ASHRAE 170 committee for guidance on future pandemics.

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While changing the pressurization from positive/ neutral to negative pressure at the space level can be a challenge, perhaps one of the most debated topics is the quantity of airflow that is required to

COVID-19 has forever changed our world and the lens through which we design through will continue to evolve. The ASHRAE epidemic task force and standards committees will continue to evaluate design requirements that will be adopted in formal standards in the forthcoming years to help direct engineers how to best design and prepare health care facilities, nursing homes and outpatient facilities during these difficult, unprecedented times. cse April Woods is a vice president with WSP USA. Woods has played a key role in engineering mechanical solutions for major health care projects over the past decade and is particularly passionate about sustainable building design and overall impact of energy efficiencies in building systems. She is a member of the Consulting-Specifying Engineer editorial advisory board.

design was flexible, which limited the need for major changes to the building system infrastructure. Based on the flexibility of the design and air distribution systems, a few motorized dampers were added to the return system and the airstreams were intercepted with new ductwork, dampers and exhaust fans to allow the air to be fully exhausted to the exterior. Permanent pressure monitors were specified at each patient room to indicate that the pressure relationship is maintained and additional door sweeps were added so the rooms could maintain a negative pressure range of 0.01 to 0.03 inches water column. This negative pressure relationship is achieved through an airflow offset between supply air and exhaust air, similar to an airborne isolation room. Although air valves at each space were considered to allow for a more automated means to switch between the pressure relationship, they were not feasible given the state of construction and already installed mechanical systems. Therefore, a manual pre/post balance is required when switching between modes to ensure the correct code required airflows and pressure relationships are maintained. Utility vent set fans were specified with bag-in/bagout high-efficiency particulate air filtration to protect www.csemag.com

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be delivered and exhausted from the space.

personnel when maintaining the fan systems or equipment nearby. Special line-of-sight studies were performed by the architect to ensure that the additional equipment views were minimized. In addition to the Level 06 modifications, provisions were made including dedicated exhaust shafts with new ductwork and exhaust fans, which will allow Level 03 to be designed as a pandemic floor when the build out occurs. Air valves will be considered in this buildout to allow for easier switch ability between the modes. When evaluating the air balance of Level 06, careful consideration was given to how to correctly pressurize each space and what rebalances of the overall AHU system would be required to ensure that the correct amount of outside air is introduced to the air system to maintain an overall positive building. The floor was designed to be slightly negative in relation to the adjacent existing tower with extra monitoring provided to indicate the relationship at the suite entrance. Evaluation of the equipment components was completed to ensure that the base equipment could handle the additional outside air load and achieve the airflow rates required and no major modifications were required to the AHUs or building infrastructure. consulting-specifying engineer

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ASHRAE statement (April 20, 2020)

“ V E N T I L AT I O N A N D F I LT R AT I O N . . . C A N REDUCE THE AIRBORNE C O N C E N T R AT I O N O F S A R S - C O V- 2 A N D THUS THE RISK OF TRANSMISSION THROUGH THE AIR”

RENEWAIRE ERVs: INCREASE VENTILATION RATES

Ventilation with outdoor air is vital to diluting airborne contaminants and decreasing disease transmission rates

LOW-TO-ZERO EATR

at typical static pressure differentials

REDUCE VENTILATION ENERGY COSTS (UP TO 65%) by reusing otherwise-wasted energy

INCREASE VENTILATION WITH A RENEWAIRE ERV “ASHRAE Issues Statements on Relationship Between COVID-19 and HVAC in Buildings,” ASHRAE, April 20, 2020, https://bit.ly/3gOiqPR.

Cores.RenewAire.com 800.627.4499

Read more about the role of ventilation in the fight against COVID-19: bit.ly/COVID19_WP

input #3 at www.csemag.com/information

BUILDING SOLUTIONS

CODES AND STANDARDS

By Michael Streich and Saahil Tumber, PE, HBDP, LEED AP, ESD, Chicago

Sustaining indoor air quality Maintaining indoor air quality is imperative for occupant health and comfort as well as the reliable operation and longevity of information technology equipment

ndoor air quality and design has historically been an important — and sometimes overlooked — design topic. When designing ventilation systems, it is imperative that the designer understand the applicable code requirements, standards such as ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality and programs like the U.S. Green Building Council’s LEED rating system. Ventilation is the process of supplying or removing air from a space to control contaminant levels, humidity or temperature. In a typical process, outdoor air and return air are mixed, which effectively dilutes indoor particulates/contaminants and the resulting mixed air stream is subsequently filtered and conditioned before being supplied into the space. Designers should always investigate outdoor air quality in their region and survey the immediate surroundings to determine the local air quality and its ability to maintain acceptable IAQ. The Environmental Protection Agency collects air quality data and has an interactive map that shows locations of air quality monitoring stations located across the United States. These air quality monitoring stations provide the required data to assist engineers with designing ventilation systems. Deficient ventilation systems, such as those operating with inadequately sized outdoor air quantities or improper ventilation control, can impact occupant health and productivity. Sick building syndrome and building-related illness are some of the negative impacts on occupant health with symptoms ranging from headaches, nausea and chest pain to asthma, Legionnaires’ disease and sinusitis. On the other side of the spectrum is excessive ventilation, which increases energy use and increases indoor concentration of outdoor contaminants if ambient air quality is unsatisfactory.

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Learning

There are studies relating sick building syndrome prevalence and the amount of outdoor air provided. These studies show that when the ventilation rate is • Understand the impact of indoor air quality on human occupants increased, sick building syndrome prevand information technology alence is reduced. There are also studies equipment. that indicate a direct correlation between performance and amount of outdoor • Understand the repercussions of inadequate ventilation and air introduced in office buildings. It is unsatisfactory IAQ on occupants important to balance the outdoor airflow and business. rate with the additional power and ener- • Review commonly missed gy required to condition the air. This is requirements of ASHRAE 62.1 and best practices to maintain where codes, standards and other rating acceptable IAQ for data centers. systems can be a useful tool. ASHRAE Standard 62.1 is frequently referenced or incorporated in codes for ensuring acceptable IAQ. ASHRAE Standard 62.1 defines acceptable IAQ as air in which there are no known contaminants at harmful concentrations as determined by applicable authorities and where 80% or more of people do not express dissatisfaction when exposed to the air.

OBJECTIVES

IAQ for human occupants

ASHRAE Standard 62.1 specifies the minimum ventilation rates and related measures to ensure acceptable IAQ and minimize adverse health effects. The standard applies to spaces intended for human occupancy within buildings except for dwelling units in residential occupancies with nontransient occupants. The origin of Standard 62.1 dates back to 1973. It has been revised multiple times since; the latest version is 2019. In addition to outlining the design requirements, the standard also provides requirements related to installation, commissioning and operations and maintenance of equipment. Ensuring compliance and acceptable IAQ therefore requires coordination and collaboration among stakeholders and continued diligent efforts on the O&M side. consulting-specifying engineer

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Some frequently overlooked items in Standard 62.1 as it applies to commercial buildings are: Design related: • Quality of ambient air and its ability to maintain acceptable IAQ should be investigated during design. The EPA has established the National Ambient Air Quality Standards as authorized by the Clean Air Act and quality standards for six primary pollutants have been established: carbon monoxide, lead, nitrogen dioxide, ozone, particle pollution or particulate matter and sulphur dioxide. –Refer to Table 1 for the EPA established air pollutant standards. –For buildings located within areas where PM10 (particulate matter with a 10-micrometer diameter or smaller) threshold is exceeded, filters or air cleaning devices with minimum efficiency reporting value 8 should be provided to treat outdoor air before introduction into buildings. –For buildings located within areas where PM2.5 (particulate matter with a 2.5-micrometer diameter or smaller) threshold is exceeded, filters or air cleaning devices with minimum rating of MERV 11 should be provided to treat outdoor air before introduction into buildings. Refer to Table 2 for filter ratings and common applications.

–For buildings located within areas where the most recent three-year average annual fourthhighest daily maximum eight-hour average ozone concentration exceeds 0.100 parts per million, ozone cleaning devices with a volumetric removal efficiency of minimum 40% should be provided. The devices need to be operated when ambient ozone levels are expected to exceed 0.100 ppm. • Following are the exceptions to the ozone cleaning requirement: –Design outdoor airflow is 1.5 air changes per hour or less. –The system is equipped with controls that can sense ambient ozone level and reduce outdoor air to 1.5 air changes per hour or less while still complying with the other requirements. –Direct fired makeup air units are used to heat outdoor air introduced into the building. • An observational survey of the building site and immediate surroundings is required to be conducted during expected hours of occupancy. The intent is to identify local contaminants that could impact IAQ if introduced into the building. • Exhaust ducts conveying Class 4 air should be negatively pressurized relative to ducts, plenums or occupiable spaces through which they

Table 1: Current air quality standards Pollutant

Primary/secondary

Carbon monoxide (CO)

Primary

Lead (Pb) Nitrogen dioxide (NO2) Ozone (O3)

Particle pollution (PM2.5)

Particle pollution (PM10)

Sulfur dioxide (SO2)

Averaging time

Level

Form

8 hours

9 ppm

1 hour

35 ppm

Primary and secondary

Rolling 3-month average

0.15 μg/m3

Primary

1 hour

100 ppb

Primary and secondary

1 year

53 ppb

Not to be exceeded more than once per year Not to be exceeded 98th percentile of 1-hour daily maximum concentrations, averaged over three years Annual mean

Primary and secondary

8 hours

0.070 ppm

Annual fourth-highest daily maximum 8-hour concentration, averaged over three years

Primary

1 year

12.0 μg/m3

Annual mean, averaged over three years

Secondary

1 year

15.0 μg/m3

Annual mean, averaged over three years

Primary and secondary

24 hours

35 μg/m

Primary and secondary

24 hours

150 μg/m3

Primary

1 hour

75 ppb

99th percentile of 1-hour daily maximum concentrations, averaged over three years

Secondary

3 hour

0.5 ppm

Not to be exceeded more than once per year

98th percentile, averaged over three years Not to be exceeded more than once per year on average over three years

Table 1: This outlines the ambient air quality standards established by the Environmental Protection Agency, known as National Ambient Air Quality Standards. Courtesy: ESD

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pass to eliminate the possibility of contaminant leakage. Positively pressurized exhaust ducts conveying Class 2 or Class 3 air should not extend through plenums or occupiable spaces other than the space from which the exhaust air is drawn. However, positively pressurized ducts conveying Class 2 air and sealed in accordance with SMACNA Seal Class A are an exception to the requirement. SMACNA Seal Class A requires all transverse duct joints, longitudinal seams and duct penetrations be sealed to minimize air leakage. Refer to Table 3 for air classification based on subjective contaminant concentration. • Filters with minimum rating of MERV 8 are required upstream of cooling coils handling latent loads and other components with wet surfaces such as evaporative humidifiers. • For buildings using mechanical cooling equipment, dehumidification provisions are needed to ensure indoor humidity levels do not exceed 60°F dewpoint at any time (occupied and unoccupied hours) when the ambient dewpoint is in excess of 60°F. Among other exceptions, the requirement does not apply to overnight unoccupied periods not exceeding 12 hours, provided the indoor relative humidity does not exceed 65% during that timeframe. • Drain pans beneath wet components such as cooling coils and direct evaporative humidifiers should begin at the leading face or edge of the device and extend downstream a distance of half the vertical dimension of the device or as necessary to limit water carry-over beyond the drain pan to 0.0044 ounce/square foot of face area per hour under peak sensible and peak dewpoint conditions. • Access doors or panels are required in infrastructure such as equipment, ductwork, plenums to allow for inspection, cleaning and maintenance of the following components:

Table 2: Filter ratings and common applications Minimum efficiency reporting value (MERV)

Typical controlled contaminant

0.30 to 1.0 microns particle size

Bacteria

Droplet nuclei

Smoke

1.0 to 3 microns particle size

Humidifier dust

Nebulizer drops

9 8

2.0 to 10.0 microns particle size

Molds

Spores

5 4

> 10 microns particle size

Pollen

Carpet fibers

Table 2: Air contaminants and the corresponding minimum efficiency reporting value rating of filters to control them are outlined. Courtesy: ESD

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The EPA has established the National Ambient Air Quality Standards as authorized by the Clean Air Act and quality standards for six primary pollutants have been established.

–Upstream of heating, cooling and heat-recovery coil comprised of four rows or fewer.

–Outside air plenums.

Construction and startup related: • Filters should be installed at equipment before startup to prevent fouling. • Contaminants generated due to construction should be confined to the construction area and migration to occupied areas should be minimized by employing suitable measures. • Drain pans should be field tested under conditions most restrictive to condensate flow to ensure they drain properly and water stagnation is eliminated.

–Upstream and downstream of each heating, cooling and heat-recovery coil comprised of more than four rows and direct evaporative coolers, air washers, heat wheels and other heat exchangers.

O&M related: • The standard has detailed requirement regarding maintenance activities and frequencies for system components that impact IAQ of the facility such as cooling towers, cooling and heating coils,

–Air cleaners. –Drain pans and seals. –Fans. –Humidifiers. –Mixed air plenums.

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Mechanical systems for data centers are unique in that their purpose is to maintain an operating temperature range and acceptable IAQ for information technology equipment.

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louvers, bird screens, mist eliminators and the like. Continued compliance with these maintenance requirements is imperative to maintaining IAQ over the life of a facility. While the designer is not responsible for the maintenance of a mechanical system, the designer is responsible for ensuring the systems are provided with the proper features to allow for regular maintenance.

IAQ for data centers

Mechanical systems for data centers are unique in that their purpose is to maintain an operating temperature range and acceptable IAQ for information technology equipment. In the United States, the Toxic Substances Control Act influences materials of construction for ITE. The TSCA does restrict the use of certain materials similar to the European Union’s Directive 2002/95/EC - Restriction of Hazardous Substances. The EU Directive restricts the use of materials commonly used in electronics and electrical equipment by banning the use of lead (with exceptions), mercury, cadmium, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers and various phthalates. Almost all major server and hard disk drive manufacturers comply with the EU Directive. However, this also causes IT equipment

Table 3: Air classifications with common examples Air classification

Description

Examples

CLASS 1

Low contaminant concentration, low sensoryirritation intensity and in offensive odor

Office spaces, break rooms, lobbies, seating areas

CLASS 2

Moderate contaminant concentration, mild sensoryirritation intensity or mildly offensive odor

Toilet rooms, parking garages, locker rooms, gymnasiums

CLASS 3

Significant contaminant concentration, significant sensory-irritation intensity or offensive odor

Janitor rooms, trash rooms

CLASS 4

Highly objectionable fumes or gases that can be potentially dangerous, bioaerosols or gases at harmful concentrations high enough to be considered

Chemical storage rooms

Table 3: Common examples of the four classes of air per ASHRAE Standard 62.1 are outlined. Courtesy: ESD

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to be more susceptible to corrosion. This led to an increase in ITE failures in regions with higher concentrations of specific pollutants. Poor IAQ can lead to premature failure of ITE and the losses can be in millions of dollars for large data centers. Gaseous contaminants such as sulfur dioxide, hydrogen sulfide, ozone and nitrogen dioxide can promote corrosion of common materials used to construct ITE. The most common failure that is a direct result of poor IAQ is creep corrosion on printed circuit boards. Silver and copper have been widely used as replacement for lead in solder. Silver and copperbased terminations on system that have corroded can lead to shorted electrical circuits on these circuit boards. Particulate contaminants (dust) can hinder cooling airflow, reduce the effectiveness of heat sinks, interfere with moving parts, cause abrasion and promote corrosion within ITE among other things. Particulate and gaseous contaminants are the most common threats to IAQ. The following are the best practices for ensuring satisfactory IAQ within the data center critical environment, based on ASHRAE resources such as ASHRAE TC9.9 white papers: • Recirculated air within the data center should be filtered using a minimum of MERV 8 filters. • Air introduced into the data centers by systems such as makeup air units, direct airside economization, direct evaporative cooling, etc. should be filtered using MERV 11 or MERV 13 filters. • Gas phase filtration should be incorporated where gaseous contamination is a concern. The corrosion rates, as measured by copper and silver foil coupons within the data centers, should be within the following thresholds: –Copper reactivity rate of less than 300 Angstrom/month. –Silver reactivity rate of less than 200 Angstrom/month. Occupants rarely think about the air they breathe — and they shouldn’t have to. Maintaining good indoor air quality is imperative for occupant health and comfort as well as the longevity of ITE. If you have questions about indoor air quality, always refer to ASHRAE for the latest research and resources. That way, your space will always be the picture of health. cse Michael Streich is senior project engineer at ESD. Saahil Tumber is technical authority at ESD. He is a member of the Consulting-Specifying Engineer editorial advisory board. www.csemag.com

BUILDING SOLUTIONS

VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE By Karen Pierce, CM-BIM, UNIFI Labs, Las Vegas

How virtual design, artificial intelligence impact engineers Architecture, engineering and construction professionals will be impacted by virtual design and artificial intelligence tools

or decades, the architecture, engineering and construction industry has developed software and hardware tools that enhance efficiencies in designing, documenting and planning throughout the building phase. In the mid-1980s, computer-aided design programs began to take over the traditional hand-drafting efforts in the workplace. Nevertheless, there was a problem with these approaches; it lacked nonphysical data and collaborative tools. Various stakeholders working on a project could not readily identify building conflicts or troubleshoot concerns in the specifications and certainly not in real time. Then building information modeling emerged in the early 2000s. This application was not just a glorified CAD product. Instead, it layered nonphysical data alongside the physical, providing a unified design schematic that brought together design, 3D visualization, building specification and project documentation. BIM also allowed everyone involved in the design, construction and implementation phase of a project to work together. It put engineers, contractors, clients and architects on the same page, allowing better collaboration. The industry is now amid an upheaval in workflows and skillsets as virtual design and artificial intelligence gain momentum. These latest trends have been gaining popularity over the past few years. Independently, both technologies have the potential to dramatically change AEC firms’ operations by enhancing their design capabilities during the design phase. On the other hand, combining these two innovations can overcome the remaining limitations of both BIM and CAD and usher in a new age for the industry. Another point of discussion is how the short- and long-term effects of COVID-19 could

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increase the use and development of these tools.

The challenge with BIM

Learning

OBJECTIVES

• Learn how artificial intelligence

and virtual design overcome Although the 3D efforts of the BIM limitations in BIM. process put forth an extraordinary effort of bringing together the broad spectrum • Understand how these innovations impact existing of interest groups involved in a typical workflows. construction project, it is not perfect. As • Identify the skill sets required to buildings become more complex, stakeeffectively use these emerging holders become more involved and with technologies. a substantial increase in client requirements, it has become increasingly difficult for AEC firms to fulfill these new deliverables using standard toolsets. Additionally, while a better specification and process might be out there, accessing it is not always practical. It has become increasingly important for firms to understand how virtual design and artificial intelligence might influence their current operations. This process may also include understanding what products or toolsets are missing and how they can take incorporate them. BIM also requires professional expertise at all points in the design phase. Before the past few years, there had been no tool to set the design specifications and then let the software discern the optimal solution. However, this is starting to change with generative design programs such as Dynamo. Although BIM initially was a one-stop-shop for whole building modeling, this conflicts with realities of delivery of building design and communication. BIM application workflows for architects diverges from BIM workflows for engineers and contractors. Getting the two to communicate effectively can continue to be challenging due to working in their different paradigms. consulting-specifying engineer

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VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE

Figure 1: This kitchen rendering was created in ArchiCAD with Cinerender. Courtesy: UNIFI Labs

Some firms try to get around this problem by increasing their software features, which often leads to diminishing returns. Somebody still has to consider all the information manually, which could lengthen the entire project schedule to an unacceptable manner Finally, for all its bells and whistles, there is one consideration that BIM cannot accommodate: the rationale behind the project itself. On physical and technical levels, BIM is sufficient at telling users whether a specification is internally consistent. However, it does nothing to ensure that designers created a specification that meets the needs of clients. This criterion is outside of its scope. The current software has no idea why it is doing what it is doing. It does not ask tough questions of designers and it does not prompt them to refocus their efforts on solutions that would benefit the end-user. All that rationalization must occur concurrently in the build phase, external to the BIM environment. That is changing.

The promise of virtual design

The AEC industry is continuously evolving and it has recognized the limitations of the traditional BIM process and, collectively, is seeking needed

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improvements — some organizational and some technological. Between 1970 and 1990, virtual reality software and hardware were in numerous industries. It mitigated risk for training the military; it advanced medical practice and even affected automobile designers. After the 1990s, virtual reality software became even more widespread as the gaming industry took off. On the surface, virtual design does not add a considerable effort to the design process of BIM. The cynic could argue that there is only a change in the user interface. Rather than reviewing designs on screen or paper, designers and stakeholders now step inside virtual versions and inspect them from the inside out. Therefore, at best, it might improve productivity by a few percent. Enthusiasts, however, view the technology differently. They contend the real promise of virtual design, they point out, is how it reshapes creativity. Even the most astute architects can struggle to appreciate the aesthetic merit of their creations looking at aerial plans alone. Architects and engineers become immersed in the action and they can do more than guess at the subjective nature of the experience. www.csemag.com

As architects and engineers navigate a postCOVID workplace, the earlier Dynamo example of maximizing desk space and minimizing unused space changes to maximizing desk space and maintaining social distancing guidelines. Virtual reality takes some of the ambiguity out of the project details. With augmented reality and virtual design, designers and stakeholders alike can get a feel for what it will be like to look out of the building from the inside — something that was not possible before. Software platforms like Revizto create explorable, true to scale virtual reality experiences within seconds. Designers can physically experience the model. They can visualize the construction project seamlessly as well as do remote walks of the site, improving troubleshooting. Designers can don their virtual reality goggles and look at a room to determine whether it makes sense. It is easy to miss noticeable flaws when looking at an image on the screen, but these flaws can become extraordinarily apparent when standing in a virtual 3D environment.

The promise of artificial intelligence

Leading AEC firms are contemplating how to implement machine learning technology to improve BIM standard practice and solve many longstanding problems with the approach. Hundreds of papers exist on the premise of artificial intelligence for a wide range of industries. In April 2019, Google released TensorFlow, a powerful and open-source machine learning platform. Users with a background in deep learning algorithms, a computer and an internet connection, now have access to a platform that could compete directly with Google itself. Before the COVID-19 pandemic, firms like EvolveLab and Smartvid.io have specialized in software platforms that harness the algorithms behind artificial intelligence. As the United States begins to reopen from the quarantine lockdown, it is clear on every construction site that safety protocols are not the same as they were. Smartvid.io uses artificial intelligence to measure compliance with proper personal protective equipment and social distancing automatically, and Smartvid.io can also analyze photos from just about any project management platform to create a virtual walk-through to detect additional safety concerns. On the design side, many firms are not applying their project data or even lessons learned from past projects to current projects. They are not applying their project data because making effective use of the mountains of data generated by construction projects is challenging. There is value in this, but extracting it is either difficult or impossible for most firms. Firms begin from nothing every time, continuing to explore only the most successful experimental learnings from earlier projects.

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Figure 2: This image is using Dynamo in Revit to review options for desk layout in an office to maximize desk area per person and minimize unused space. Courtesy: UNIFI Labs

Figure 3: A Hypar workflow shows several generative design options for the building design. The current service core option is displayed in context with alternative options available for selection. Courtesy: Hypar.io

With artificial intelligence, however that could all change. Artificial intelligence combined with BIM data could allow AEC firms to go far beyond rational analysis and at a much lower cost. Engineers could connect artificial intelligence tools to their databases, feed them data and then extract new insights. Artificial intelligence may also enter the BIM market in another way: by allowing specialists to explore the space of construction more rapidly. consulting-specifying engineer

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VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE Working out whether a design is possible requires the manually intensive endeavor of physically going in and creating it. With machine learning, it is possible to effectively “evolve” a design that meets specifications. Architects and building contractors could set the parameters and then tell the computer to continually try new combinations until it produces something that fulfills the client’s criteria. Design specialists then use their judgment to review the machines’ design outputs and decide which designs take the next step. Artificial intelligence may also be able to help at the data classification level. Inspecting each element of a BIM model and then assigning it to a category is a tedious task. AEC professionals spend an enormous amount of their time, inputting specific details to ensure that BIM projects remain robust and collaborative. However, machine learning could easily take over this process by looking for commonalities among elements, scanning each data point in BIM design and assigning a category. If the machine cannot figure it out, the machine can ask a human to categorize and store the added information in its databanks.

Evolving AEC workflows

Throughout the design and engineering process, AEC firms collect data from a broad array of sources such as design criteria, simulation data, structural analyses and similar. Historical-

ly, this information was stored in a repository and remained unused and unloved. With the advent of machine learning, it is now possible to use it for many project-related purposes. These include: • Generative design. • Managing risk. • Denoising rendering. • Budgeting. For example, rendering a true-to-life model of a project on the computer once took hours to achieve. However, when engineers added denoising algorithms to the graphics processors, it significantly reduced the raw data necessary to produce a viable visual output. Artificial intelligence could allow designers to make changes much faster than in the past, allowing them to modify building aesthetics in near real-time. We will see something similar happening in the realm of generative design as well. Workflows will change from the current BIM paradigm. Teams of designers and engineers will no longer need to manipulate the design structures manually and continually check their viability. Instead, a machine learning algorithm will use mountains of data to simulate a series of design experiments subject to user-provided constraints. It will then develop a set of solutions, trialing different approaches until it finds one that satisfies the user’s specifications.

CASE STUDY:

Autodesk’s generative design artificial intelligence

hile there are numerous examples of proj- and research space in Toronto’s MaRS Discovery District. ects implementing both artificial intelligence The company wanted to facilitate happenstance interand virtual design across the construction actions between various innovators and personalities. The resulting cross-referencing sector, generative machine learnand interaction of ideas, it hoped, ing is arguably one of the most Human architects looked would aid competitive advantage. interesting. over the designs and deNevertheless, the compaGenerative design is an artifiny knew that getting designers cial intelligence-guided tool that cided which they thought to manually produce such a conmimics nature’s evolutionary prowas best from a broader figuration would be a challenge cess. A computer algorithm experperspective. because it is not an easy thing for iments with an initial design and people to think through naturally. then modifies it repeatedly to see whether it better fits the desired outcome parameters. Designing a space to encourage random interactions is After millions of attempts, it eventually produces a solu- a big challenge for human designers, but artificial inteltion. Usually, it is better than anything that a team of ligence can do it with relative ease. Autodesk started experts could design, making it one of the most potent setting up the parameters that would allow it to use artificial intelligence to design a space generatively. artificial intelligence applications. The team had the concept set in their minds; It was Autodesk was quick to see the technology’s potential and decided to put it to use in designing its new office just a matter of providing the generative algorithm

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Figure 4: This infographic highlights this generative design process. Courtesy: UNIFI Labs

Because of the fluidity of artificial intelligence, workflows may wind up looking quite different. Designers and architects will no longer be down in the trenches, dealing with the details, such as whether a wall can support a load. The artificial intelligence will do that. The engineers’ role will be setting the constraints, specifying the parameters and evaluating whether the arrived-upon designs fit the client brief.

The way companies go about budgeting will change dramatically too. Cost flow information already forms part of the accessible datasets. Artificial intelligence systems could potentially calculate the costs of real-time projects by incorporating learnings from prior builds. As projects progress, engineers and designers could add new elements to the BIM models and then determine how it affects their artificial intelligence-generated budget.

with data that it could use to develop an optimal layout. Once the generative algorithm was developed, the artificial intelligence could experiment with room features and fictitious human agents to see what type of setup would achieve Autodesk’s goal. The entire process was over very quickly. Using the latest supercomputers, Autodesk ran through approximately 10,000 iterations in just a few days. Once completed, the computer gave a short list of arrangements to meet the goals while complying with constraints. Human architects looked over the designs and decided which they thought was best from a broader perspective. This innovation flipped the design process on its head. Architects and planners turned from artists to reviewers. Their role went from assembling the design to review it. They provided high-level input but no longer needed to drill down into the details. Autodesk recognized this was merely the beginning as they realwww.csemag.com

ized that they could use generative design to optimize a range of other factors vital to an efficient building project. They concluded that generative design could maximize construction efficiency, budget efficiency and a range of other factors. Thus, Autodesk could apply this particular artificial intelligence technique to the final design and the planning process. The idea had the potential to slash their costs, reduce construction time and offer practical compromises with other end goals specified in the original parameters. In short, it made rational, data-driven, multivariable optimization feasible. These high-level overviews would then feed into virtual design considerations, improving the information available to those involved in the construction and planning process. Clients would be able to see tradeoffs between different directions in ways that were not possible in the past. consulting-specifying engineer

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BUILDING SOLUTIONS

VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE In a sense, therefore, both virtual design and artificial intelligence force engineers, architects and builders to take a step back and ask the more important questions. These innovations will protect them from becoming bogged down in the details and focus on the clients they serve.

Skill sets required

Both virtual reality and artificial intelligence are valuable innovations for the AEC industry. However, unless firms learn the necessary skills, they will not be able to leverage them and rollout will be as slow as it was for BIM.

Do they want to spend more money and complete the project faster? Do they want to achieve a higher-quality design, but dedicate more time to the project? What about a project that delivers the smoothest crew cadence at the lowest cost? Thus, when AEC firms introduce artificial intelligence to the design process, they wind up requiring professionals who can make executive decisions according to entirely new schemas that will be need to be addressed. Management and planning skills — Management and planning have always been critical in the AEC sector, but these innovative technologies will change the game. artificial intelligence-optimized workflows will make the task of site management more data-driven. Those in charge will see a shift from the day-to-day practicality of keeping the wheels of the project, moving to plan how things will unfold ahead of time. Managers need to become comfortable with the idea that they must create plans that satisfy multiple criteria relating to time, cost and crew availability.

Artificial intelligence, virtual design and AEC firms

Figure 5: A Hypar workflow showing a generated building design in a referenced urban context. Additional generated façade options are available to replace the current façade design. Courtesy: Hypar.io

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Data and artificial intelligence skills — AEC firms will always need personnel who understand how to use and implement their data and artificial intelligence resources effectively. Still, collecting, managing and interpreting data requires human interaction. artificial intelligence will also not tell companies how or when to deploy the software, share best practices or lessons learned. They will still need people for executive decision-making. Data and artificial intelligence will usher in a new paradigm for the sector. Rather than a single design possibility (the result of a traditional collaborative BIM endeavor), generative artificial intelligence will produce a menu of options. Firms will need people with the skills to evaluate each and select the best to support the desired outcome. Companies will also need professionals who understand how to label data and link it to new artificial intelligence tools. Practically all data firms collect throughout their operations is valuable but putting it to effective use is a challenge. Cost and scheduling skills — Under traditional BIM workflows, there is a simple analysis regarding the timeline and cost at which projects achieve completion. However, when using artificial intelligence, this will no longer be the case, as superintendents will have the option of weighing different considerations against each other.

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Whether artificial intelligence and virtual reality will solve all the problems inherent in BIM remains to be seen. Human error will remain an obstacle for some time, but the stumbling block’s nature is going to change. No longer will it be incongruities in BIM that hold up projects. Instead, it will revolve more around the misapprehension of client needs. artificial intelligence will take care of a lot of the grunt work that goes into the design, but there will still be a need for human decision-making at an elevated level. That is never going to go away. AEC companies that can position themselves to take advantage of these technologies will gain a competitive advantage. artificial intelligence will enable them to assess clients’ needs better and ensure that they meet them, regardless of what software tools they use. That same technology will revolutionize the design process itself. Professionals will find themselves engaged in radically different workflows that require entirely new skill sets. How AEC firms operate, therefore, is going to change significantly in the future. Development time will decrease and the quality of service will improve. As virtual design and artificial intelligence workflows evolve, it will lead to less worrying about the details and more focusing on the big picture. cse

Karen Pierce is a senior BIM specialist at UNIFI Labs. She has 10 years of experience in the AEC industry and has led the charge on expanding BIM technology in various roles. www.csemag.com

BUILDING SOLUTIONS

VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE By Joel Martineau, LEED AP, Stantec, Washington, D.C.; Jim Marchese, Stantec, Philadelphia; and James Mazza, Stantec, Saskatoon, British Columbia

How virtual design changes the way we work Communication is required for good design, but does it need to always be in person? Virtual design is an option for coordinating building plans virtually

ngineering design is the process by which we transform a set of requirements into an initial building concept, further develop it to comply with various criteria such as local regulations, life safety and engineering principles and finally erect a building. This requires the input of multiple participants — the client, design consultants and a contractor — across various stages of the project. In the past, face-to-face meetings were always preferred as it was important to connect, sometimes literally flipping through sheet after sheet of construction documents to ensure everyone was on the same page. Communication is required for good design; but does it need to always be in person? In this age of technology, we have the opportunity to share not only our ideas but explore potential solutions in myriad ways. Queue virtual design.

Virtual site

Learning

For a current project in Philadelphia, the Stantec team is converting 96 medical surgery rooms to acuity adaptable • Identify opportunities to communicate virtually with rooms. Because the hospital will remain the design team, clients and open during this conversion, only six contractors. rooms can be offline at a time. This • Learn various technologies that makes it difficult to design new shafts can be used to collaborate. through the building to accommodate • Understand where virtual new systems. In addition, the plenum solutions can improve the design is full of existing systems that must be process. maintained. To have a complete understanding of the limitations, the engineering and design team began to research reality capture technology to develop a better sense of what existed. The first step was to develop a list of requirements for the density of scans both above and below the ceiling and the delivery format for the scan files, in conjunction

OBJECTIVES

Figure 1: This example shows a live meeting between consultants in a virtual environment via InsiteVR. Courtesy: Stantec

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VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE oped custom space planning families in Revit, which are designed to be very conceptual in nature. Each breakout facilitator will use Revit to move the various game pieces around the game board, guided by feedback and decisions from the client, with participants viewing the process via Teams. • Once the required number of design options are complete, the facilitator will create a PDF of those options. All participants will then reconvene in the large group meeting, where the breakout facilitators will add their PDF to the large group whiteboard using the Microsoft Whiteboard as its canvas. Figure 2: The plenum space in a building is viewed via Cintoo, a webbased point cloud management system to assist in viewing the massive scan files. Courtesy: Stantec

with the surveyor. The team then used Cintoo, a web-based point cloud management system to assist in viewing the massive scan files. The team invited all project members to the web platform, including the construction manager’s advanced coordination team and the client. Cintoo simplifies the interpretation of point cloud data. It provides several options for viewing as well as measurement tools. The team can selectively export portions of the scan to bring small, lightweight parts into Autodesk Revit. Once the model is developed, the team can heat map it against the point scan to detect differences, ensuring the team achieve the level of accuracy necessary to document the existing conditions. This platform has enabled Stantec to move forward with a complex project despite the design team never visiting the project site. This type of remote access has proved especially important during the current pandemic.

Virtual charette

An important step in the design process is to review the initial program provided by the client. The team is exploring various technologies to mimic design charettes in a virtual environment. The team uses Microsoft Teams to organize a large group meeting with the Stantec design team and client participants to outline the various “rules” for the spaces the team are designing, facilitated by a Stantec team member. The process is: • All attendees are separated into groups and assigned to various breakout group channels in Teams, each with a Stantec team member as the breakout facilitator. Each breakout group starts its own Teams meeting, allowing screen sharing and video conferencing. • To simulate the process of using “game pieces” and a “game board,” Stantec has devel-

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• All participants of the large group meeting can then use the markup tools in Microsoft Whiteboard to vote on favorite design options. Because this process uses Revit, the crew can begin to incorporate those design options into an early conceptual model. The team has also developed a custom tool to replace the conceptual space planning families with Revit room objects, seamlessly bringing the group from schematic design into design development and beyond. Virtual charettes have been pivotal in encouraging project teams to embrace innovative workflows and ensure the team are using technology to stay connected.

Virtual collaboration

Most projects involve a project team that is geographically distributed. Add external consultants, clients and the contractor and it becomes readily apparent: collaboration with multiple stakeholders can be a challenging task. Each stakeholder has its own internal systems to store project data, which results in silos of information. This is not truly collaborative. To achieve collaboration in the purest sense of the word, the entire project team needs to access project data from the same environment. In a similar fashion to the virtual charrettes, Microsoft Teams provides a platform to share and contribute to the development of a project. When structuring data, consider the following: • Microsoft Teams is a platform for information such as a project directory. Locating as much content as possible on Microsoft Teams or other cloud platforms instead of internal systems will ensure all parties are referring to the most current documents and files • Clients are often best restricted to their own area to manage the data they have access to. Consider the use of private channels www.csemag.com

CASE STUDY:

How clients benefit from VR

• Make use of the other tools integrated into Microsoft Teams such as Microsoft Planner. It is a powerful tool that allows you to easily assign tasks and due dates. The team is also using Autodesk BIM 360 to enable internal and external partners access project data. This provides an environment for nonRevit users to review models, in both 2D and 3D and comment on drawings. This lessens the detachment of project managers that are not modeling from what is being constructed in the models and provides the flexibility to view it from anywhere at any time and on any device. All of this is underpinned by Newforma, a project information management solution. It integrates with current file servers and project folder infrastructure as well as the applications mentioned above. It saves time, streamlines workflows, mitigates risk, improves responsiveness from external team members and increases accountability. Adoption is often the most challenging obstacle to overcome when implementing new platforms on a project. Members must be consistently encouraged to post content in the correct location and reminded that specific file types have different sources of truth. This reinforcement will help team members to develop routines and habits that result in increased efficiency.

Virtual reality

As the project team collaborates and begins to flush out the various parameters of a project, a solution is developed. The medium of choice to do this is drawings, namely plans and elevations. As professionals in the architecture, engineering and construction industry, the team has been trained to interpret drawings. However, clients may not be able to do this. This is a risk, as the team does not want to proceed with construction only to find out after something is built that it does not truly reflect what a client had in mind. This provides the opportunity to use virtual reality, where the design team provide computer-generated representations of the designs for clients to interact with. Two options exist: • Stereoscopic panoramas can be generated and shared via an online link. The client can then open this link in a web browser and view the design from a single vantage point, with the option to swivel their line of sight a full 360 degrees, as well as up and down. This experience can be further enhanced by providing links within the panorama that teleport the user to another location, so they can virtually travel through the building to visit multiple spaces.

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efore wrapping up the design development phase, the team invited the client to the Stantec office for an interior design presentation and virtual reality tour to receive final approval. Often, the team finds that showing just plans, elevations and 3D views is not enough to properly convey design intent. As designers, it is second nature to mentally place ourselves in the spaces the team has created and imagine how it will feel once built. The Stantec team uses VR as a communication tool to allow clients to understand spaces in the same manner. During the presentation, the client expressed concern about a focal ceiling element that was shown in a rendering. The Stantec team used our words, hand motions and reflected ceiling plans to try to explain how it would feel better when standing in the space. The client was still not convinced and was hesitant to approve the design. The team gave the client a VR headset and allowed them to occupy the space and understand the design from a 360 perspective. Having the opportunity to use VR technology allowed us to clearly communicate our concept to the client and gain their consent to proceed. There is a misconception that VR is only useful for aiding clients with understanding aesthetic elements of a project. Our engineers are using VR to validate spatial requirements in crowded plant rooms with client facilities management teams. For an urban infill project located in the city center, the team provided engineering services. The mixed-use nature of the project led the design team to incorporate a midheight plant room to serve retail and restaurant in the lower floors from above and the hotel on the upper floors from below. Due to the tight constraints of limited floor plate and floor-to-floor height, it was imperative to develop a detailed plant room during the early stages of the project. The team modelled the ventilation system, hot- and coldwater supply and heat generation plant along with the structural framing system to assist with optimizing the minimum required clearances. A series of stereoscopic panoramas were then generated to prove and validate that sufficient space allowances were provided in front of all mechanical, electrical and plumbing systems with the stakeholders. In both scenarios, our Stantec team used the power of virtual design to strengthen the interaction with the clients. By using technology to foster innovation and creativity, the team is improving the design, Figure 3: Virtual reality allows delivery and handover of clients to become fully immersed in the design. Courtesy: Stantec buildings to the occupants. consulting-specifying engineer

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VIRTUAL DESIGN AND ARTIFICIAL INTELLIGENCE • When providing the option to view only from predetermined vantage points is not sufficient, the team provides virtual environments. The premise is the same as above, and allows users to virtually walk through the designs so that they can better explore the entire space. This allows users to choose their vantage points within a building and even ascend staircases.

• Content: Consider altering what the actual experience will be to ensure the purpose of exploration can be achieved. If you are exploring the access of equipment in the ceiling plenum, consider making the ceilings transparent so they provide the context of where the equipment is located, but make it easy to see in order to generate comments.

For a more immersive experience, both options above can be enhanced by using VR headsets. In lieu of viewing designs on a monitor, users put on headsets that allow them to rotate their heads, mimicking real life, to view what is around them. Care should be taken to ensure that anyone with a headset on is situated in a clear space where there are no objects that serve as tripping hazards. To make virtual exploration of designs a worthwhile experience, the following should be considered:

Remember the intent of using VR; determine what feedback you are trying to elicit from your client. If you are more concerned with getting their opinions about the size of a space, consider using a single material to display all content. Focusing the client’s attention on the desired task is important to achieving the desired result of confirming the design is satisfying their expectations.

• Scope: Provide small scenes for the client to explore, versus everything at once. This will improve the quality of the experience as the files associated with this will be smaller. Concentrate on focal points of the design, such as mechanical or electrical rooms, or corridor spaces where MEP systems tend to run in constricted spaces.

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As more design data moves into digitized forms, it becomes ripe for various applications of artificial intelligence.

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Figure 4: In this digital game board with space planning pieces, game pieces are moved around the game board, guided by feedback and decisions from the client, with participants viewing the process via Microsoft Teams. Courtesy: Stantec

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Virtual coordination

As part of the design process, Stantec designers develop many of the building systems required, resulting in a virtual representation of the final project as a series of 3D models. One of the muchtouted benefits of building information modeling is the potential to improve the design and coordination of building systems. Using tools such as Autodesk Navisworks to manage the clash detection process and produce a list of potential conflicts is great. However, the results of this exercise are then viewed as 2D representations of the conflicts and discussed at a separate coordination meeting. Because communication is so important, the teams are taking coordination one step further by using InsiteVR, which allows team members to interact while being connected in a virtual 3D environment. Models can be viewed via VR headsets or on monitors. Attendees have access to mark-up tools, voice-to-text to capture comments and can even sketch alternative design options overlaid on top of the virtual environment. Other functionality includes the ability to interrogate the parameters of model objects and take measurements. To ensure everyone is on the same page, the person speaking can replicate his or her point of view to all attendees. Once the meeting is concluded, a formatted PDF of all the comments and markups is generated and emailed to the meeting organizer for distribution back to the team. To truly take advantage of this process, consider: • Organizing the project in a manner that considers your virtual meeting. If you would like to focus your discussion on a specific area or function, set up a view that isolates that information. You can load the view directly into the meeting in advance, so attendees do not waste watching you set up the virtual environment. www.csemag.com

Figure 5: Using virtual collaboration, the team is able to establish the correct locations for various types of project data. Courtesy: Stantec

• Treating this like any other project meeting. It is important that the entire design team attend, not just the team responsible for BIM and modeling. Schedule meetings on a regular, repeating schedule related to the deliverable schedule, so team members not only stay familiar with the tool but also have their models submitted for review. InsiteVR brings all team members into the active production space, facilitating real-time discussion about potential conflicts and omissions. This distinction is important, as it combines the work done to setup and run clash detection before reviewing the results at a coordination meeting into one exercise, saving overall project time and increasing efficiency.

Artificial intelligence

As more design data moves into digitized forms, it becomes ripe for various applications of artificial intelligence. From apex systems such as Google Assistant and Alexa to the algorithms that power modern spam filters and Microsoft Excel’s flash fill, the past several years have seen several

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generalized artificial intelligence technologies surface within the industry. In general, these are not specific to architecture, engineering and construction, but are characterized by automating repetitive or mundane tasks. For example, image classification is a relatively well-understood task within the machine learning world. Being able to search images for specific items automatically has been successfully applied in the construction industry to assist with site assessments and safety compliance. Similarly, nonphysical chat-bots, such as those available on Microsoft Teams, help simplify work by assisting with searching through chat history or reserving meeting space. It’s expected that, as these bots and the natural language processing systems that underpin them improve, the team will be able to quickly sift through virtual design files for answers without needing to unroll a drawing set or open a PDF. cse Joel Martineau is a senior business solutions analyst at Stantec. Jim Marchese is a senior business solutions analyst at Stantec. James Mazza is an application developer at Stantec. consulting-specifying engineer

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BUILDING SOLUTIONS

DESIGNING FOR RESILIENCY

By James D. Ferris, PE, TLC Engineering Solutions Orlando, Fla.

How operational understanding leads to resilient design Designing a resilient building requires understanding of both the built environment and operations for critical facilities

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esiliency is defined as “the capacity to recover quickly from difficulties; toughness,” or “an ability to recover from or adjust easily to adversity or change.” Resiliency in design and the built environment can be taken to mean many different topics, but, in general, it’s that the building continues to function as it was planned and intended. This requires operational understanding, proper risk analysis and finally design execution. Unfortunately, risks are everywhere and engineers and building owners can’t truly prepare for every contingency. For each risk, the designer should consider how likely it is to occur, what the impact occupant safety and security and what the potential solution is to mitigate the risk. What is a built environment risk and what is something that can be accomplished via an operational plan in the event that risk does come to pass?

During an event, which might last minutes or a day, a facility director will focus on the most important items at that time, items that can have an impact to safety of the occupants.

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It seems silly at this point to write about why resiliency is important with COVID-19 challenging our lives and our buildings. Unfortunately, COVID19 is only the latest and most devastating of events that have occurred over the past decade around the world and the United States, both from the aspect lives lost and the cost. When evaluating each facility, approach it with the following three questions:

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• How would the owner want to operate during and/or after an event? • What are the possible failure points and the risk? • What can be done about it?

Operational considerations

How a facility operates becomes an answer that informs the rest of the analysis. Engineers need to have this basic understanding even before doing a risk analysis. Some risks can also be mitigated by the operational plan for any facility. If the goal is for a building to operate as intended, then this step comes before risks are identified that will cause a deviation from that operation. Commercial buildings, theaters or restaurants, for example, most likely shut down during an event, but want to start up afterward. To demonstrate the importance of operational awareness consider this cause and effect analysis for a commercial restaurant: Does the owner plan to be present at this facility for an outage? If no, the facility will need to operate without human intervention. The owner may also want to know status of the building from afar — this means alarm points, monitoring and possibly remote controls. The internet connection is a critical service that needs to be protected. How soon after an event will the facility be open? If operations will begin immediately after an event, the owner needs to ensure that structural damage, debris or flooding would not affect the interior of the restaurant. This would impact what kind of glass is used or how the envelope of the facility is designed. It also would affect the locations www.csemag.com

Learning

OBJECTIVES

• Evaluate and understand design parameters for facilities. • Learn about risk analysis and why it is important in designing for resilience. • Know the considerations for design for envelope, structure, fuel and emergency power.

of utilities and necessitate enhancement of protection of equipment. How will food storage be handled in a power outage? Different owners have different tolerances for risk. When power goes, food stored on-site starts to go bad. Does an owner have those refrigerators on emergency power, or do they accept the risk of that loss? If the owner accepts the risk of this loss or has an operational plan to use it up before an event, then power outages become a less critical failure point. What maintenance contracts does the owner have? Consider the generator above for food. Who is doing the testing for that equipment and making sure it will run when needed? What equipment is most critical to the function as a restaurant? Operational requirements such as a grill or a cash register would lead to design considerations for the exhaust over the grill, review of the gas service supply and knowing the power and internet connection for the cash register/ card swipe is of elevated importance. How long of an event does the owner want the engineering team to consider? This is a big question, especially when it comes to fuel. If there was an outage, how long do the refrigerators have to run?

Mission critical facilities

Hospitals, fire stations, police stations, news facilities and data centers will all want to remain fully functional during any event, elevating the need for operational understanding. To demonstrate the impact of this understanding, let us consider it through the eyes of a hospital facility director. During an event, which might last minutes or a day, a facility director will focus on the most important items at that time, items that can have an impact to safety of the occupants. Patient care is highest priority at all times, but during a storm or emergency event, elective surgeries and outpatient procedures may be stopped. This is the first operational question, and that answer will impact how much fuel electrical engineers plan for if there will be redundancy in the generators and equipment serving operating rooms. Next, a facility director would worry about how they will keep the lights running and if the utility power is suddenly going to drop. A key operational element is when a facility switches to emergency

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Figure 1: This generator system had remote radiators cantilevered off the building, creating a large risk to the emergency operation of the facility. Engineers should consider what happens in a hurricane. How would operations and maintenance teams properly maintain and visually inspect this every week? Courtesy: TLC Engineering Solutions

power — often they do not wait for the utility to drop them, but make an orderly transition to emergency power when they start to have power quality concerns. They might be worried about damage, like a leak or a sudden breach to the facility that occurs during the event and how are they are going to temporarily make it safe and respond. As an example, a hospital expressed that a rooftop door was pulled open from a hurricane and was swinging wildly in the wind. It became a sudden activity for them to figure out how to close it and make sure it stayed that way. They now have an operational plan that requires them to secure doors before a possible hurricane, especially these rarely used ones. Many times, they learn truly what is on emergency power and what is not. One facility realized midevent that they had backed up their cooling towers with emergency power, but there were some control sensors that were powered from normal 120-volt power. How much longer is the list of a facility director’s concerns after the event? Generally, that list immediately after event is much longer and sometimes more concerning. Part of it is that the owner gets a chance to stop and think about any concerns. Also, priorities change on what concerns are the most critical. Power outages, for example, become less critical once operating on generators for a while. At that point, fuel starts to become a very big source consulting-specifying engineer

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of stress for the facility. Every hour of the event and every hour after reduces a finite resource in fuel. Considerations include when the tanks will be refilled, the state of roads and a preplanned and reserved fuel supplier. During Hurricane Irma in 2017, more than 60% of Florida lost power, some locations for as long as two weeks. That is a long time to go on emergency power and would likely require several fillups of fuel tanks during that time. Flooding is the No. 1 source of damage, both during the event and continuing after the event. Finite stockpiles such as water, food, supplies for repairs and personnel start to become real concerns for facilities. Critical facilities like hospitals also end up with extra occupants. Hospital staff often bring families for predictable events. Patients have extra visitors that become overnight guests as well. Interestingly, facilities end up with a much greater demand from additional use of towels; the on-site laundry facilities often cannot keep up.

Failure points and risk analysis

A review of the facility planning is the first item that should be on any risk analysis. A lack of documentation on how a facility would prepare for an event or function in an event is a major risk item. Many of the concerns outlined in the operational section are items that can be planned around, but not if they are a surprise during an event. The engineering team should help clients plan for:

• Evacuation plan: Define the criteria for deciding that a facility should be closed. • Proactive testing and maintenance: Determine whether preventive maintenance on the essential generators must be performed, among other tasks. • Event simulations: Conducted before any event, a simulation would test how its occupants function in event and after of an event. The next step would be to go through a facility and identify the possible failure points, how likely they are to fail and what the impact would be. Common failure points include: • Many older cities have power lines overhead, creating risk in snow or storm events. • Flooding is the most common source of damage. Roofs and the building envelope should be reviewed. • Failure based upon age of equipment: Many facilities operate with equipment that was made more than 40 years ago, with no available replacement parts for that equipment. It creates a situation that is an elevated risk due the duration that they could be out while they find obsolete parts. • Lack of proper maintenance on equipment. • Limited awareness of how systems interconnect. • No documentation for redundancies put in place or directions on how to implement.

Figure 2: It’s important to consider appropriate louvers and risks to building envelope when designing resilient buildings. This louver was designed structurally with an extra 10-inch cantilever to support new remote radiators for the same site. Courtesy: TLC Engineering Solutions

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The amount of emergency power is a big question for any facility, and what is connected to it is just as important. The biggest load in most facilities is the heating, ventilation and air conditioning system, in particular the cooling system. These are not code required to be on emergency power for many facilities, but lack of backup to these systems have caused deaths in several events. Nursing homes, for example, frequently have emergency-powered HVAC for all spaces or emergency-powered HVAC for common spaces and an operational plan to relocate residents in a power outage to that space. COVID-19 has brought a new element to the risk analysis for all building types. One common element of resiliency is to continue to function while protecting the occupants. Every facility has some risk in the spread of the virus in how air is distributed, what is done to filter air and much www.csemag.com

fresh air is brought in. There is no question: COVID-19 and viral transmission within facilities will be an item of concern for owners everywhere.

Figure 3: A common miscalculation is to take the nominal fuel in a tank as the available capacity. Engineers need to understand what fuel that is truly available for use. Courtesy: TLC Engineering Solutions

Design considerations

The most important systems to get right the first time are the building envelope and structure. These are very costly to fix and upgrade to meet high levels of reliability and redundancy. It’s important to consider every opening within the building as potential failure point — the types of windows, doors and louvers should be reviewed. There are many manufacturers that create louvers that are designed to withstand the impact of a 2x4 hitting it at hurricane speeds. All openings should be protected; how to maintain those openings to the desired level should be considered. An example of this would be a facility that has hurricane shutters, and needs to annually install and uninstall all shutters to ensure they fit and the right bolts and attachments are still functional. It can be a significant maintenance item to opt in to shutters over higher cost/higher quality windows. Emergency system gets a lot of focus, but what really is on emergency power? Too many facilities are only backing up code-minimum elements. The simplest thing a facility can do is to have an electrician install meters on the facility. With metering on key loads, the owner will get a great understanding of how much capacity it would take to add that to the backup system. Generally, it’s recommended that all HVAC and critical functions be on emergency power if the owner intends to operate through an event. Some things, such as kitchen equipment, need to coincide with food preparation plans to remain open. If the plan says to serve nothing but peanut butter and jelly sandwiches, storage is required for all of that, but not a lot of power. If the plan says the menu will remain the same, then the owner will have to provide emergency power for each type of cooking equipment at minimum. Fuel systems often are an extreme source of stress. The proper calculation for available fuel in the tank is to consider the volume between the maximum fill level of the tank and the bottom of the usable fuel. Both items are available from the manufacturer and should be used in understanding how much fuel is truly available. For example, a 5,000-gallon tank might only have around 4,200 gallons of usable fuel. The size and shape of the tank matters as well. But once an owner has fuel, having some extra is good, but having too much can be just as much a problem as having bad fuel. Fuel quality is equally important; poor-quality fuel can cause an emergency system to fail. Many facilities either opt to have a standing fuel polishing program or install an automatic fuel polisher to maintain high-quality fuel.

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The most important systems to get right the first time are the building envelope and structure. These are very costly to fix and upgrade to meet high levels of reliability and redundancy.

A simple, but often overlooked element is landscaping and site grading. Location of cooling towers adjacent to trees that aesthetically block them becomes the reason they fail during a hurricane. The debris from the trees cause blockages within the cooling tower basins and also get5s into the pumps. In cases where generator louvers located where snow drifts will accumulate, the generator doesn’t get the air it needs, so it won’t work. Again, many of these become operational plans for trimming trees and clearing snow, but could they have been designed differently to not require those operational plans? With the pace of events over the past decade and continuing into 2020, resilient design is going to become more important. Engineers need to design facilities that are functional, can survive weather events, consider health of its occupants and not need to be replaced over the next 20 or 30 years. cse

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James D. Ferris is COO of TLC Engineering Solutions. He is a 2012 Consulting-Specifying Engineer 40 Under 40 award winner. consulting-specifying engineer

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By Nancy Kohout, PE, LEED AP BD+C; SmithGroup, Chicago; John Rushing, SE, RA, LEED AP, SmithGroup, Chicago; Bill Wood, PE, SmithGroup, Chicago; and Valerie Berstene, AIA, LEED AP

Harnessing an interdisciplinary team for resilient design By collaborating with an interdisciplinary team, engineers can offer high-value, holistic solutions that promote resilient design for buildings and sites of all types

hrough resilient design, engineers can prepare for catastrophic events, address underlying stresses and adapt to changing conditions. This process of resilient design addresses physical infrastructure and organizational networks to adapt and rebound from the impacts of climate change and man-made disruptive events. We believe that an integrated approach where mechanical, electrical and plumbing teams work collaboratively with architects, structural engineers, civil engineers and landscape architects is critical for effective resilient design. What good is a state-of-theart facility if the power fails? A hospi• Apply an interdisciplinary team tal that remains operational through of engineers and designers to a hurricane is only functional if it can identify shocks and stresses to be accessed via clear roadways. design for resilience. Through frequent, collabora• Identify strategies for resilient tive problem-solving, a design team design and evaluate strategy and building owners/operators can costs and benefits. optimize solutions against potential • Understand how MEP threats, creating facilities and commuengineering solutions can offer resiliency for sites and buildings nities that are better poised to address in the face of weather events. the changing world around them.

Learning

OBJECTIVES

Identify the threats

To appropriately plan and design for resilience, it is important to understand the risks and underlying vulnerabilities our communities are facing. The terms “shocks” and “stresses” classify hazards that impact buildings and communities. While commonly identified as natural disasters, shocks can also be a result of human behavior. Shocks can be catastrophic at local, regional and global scales. The

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enormity of their widespread devastation grabs our attention. It is important not to lose sight of the communities and people impacted during these events as the facilities and systems we design can help change their outcomes for the better. Stresses are chronic, long-term issues and can be just as impactful as shocks. As stated by the Rockefeller Foundation, pioneer of 100 Resilient Cities, “Stresses are slow-moving disasters that weaken the fabric of a city. They include high unemployment, overtaxed or inefficient public transportation systems, endemic violence and chronic food and water shortages.” Whether a strain on social structure, buildings or the natural environment, stresses heighten a community’s vulnerabilities and reduce its ability to respond to and recover from a disaster. We are experiencing the amplifying power of stresses during COVID-19. Evidence is clear that historically underserved neighborhoods with less access to health care, healthy foods and essential services are having disproportionately higher numbers of cases and death rates. Stresses undermine communities and act as “threat multipliers” when they coincide with a shock, exacerbating potential devastation. For instance, a city’s ill-maintained drainage infrastructure reduces its capacity to handle severe storm events, increasing flood risk within the service area. With the interconnectivity of our natural and built environment, an initial hazard event can trigger subsequent or secondary hazards. With increased flood risk from a lack of maintenance, a severe storm can result in community flash flooding as the secondary hazard. www.csemag.com

Figure 1: Multiple shocks and stressors, such as a severe storm event and poor city infrastructure can lead to secondary events such as flooding, which can lead to events like power outages, landslides and hindered emergency response. An interdisciplinary approach to resilient design can anticipate and reduce the impact of cascading events. Courtesy: SmithGroup

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At the beginning of every project, the interdisciplinary design team should work with the client

From there, ongoing hazards can occur as cascading events such as the floodwaters creating a landslide or a power outage. These cascading effects increase a community’s vulnerability and exposure to larger threats, compounding the challenges a community faces during recovery efforts.

Establish resilient design goals

At the beginning of every project, the interdisciplinary design team should work with the client to identify their goals for resilience. The project location will determine potential threats. Clients’ needs for operations during a disaster or during recovery often vary. A hospital and an office building will have different requirements for operations during a disaster. This need for continuity of operations and ability to rebound from a disruption is called a “level of resilience.” Bringing all the design disciplines, the owner or client and the end users together in a workshop is the best way to understand the potential hazards, cascades and threats to life safety and facility operations. Preparing for the workshop begins with identifying the possible shock events and underlying stresses that may impact the site, the building and its operations. Several resources for identify-

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to identify their ing threats by locale are listed at the end of this article. With these resources, the goals for resilience. design team should develop a matrix of potential hazardous events. This matrix The project locashould include information on duration, severity, probability of occurrence and any tion will determine secondary or cascading hazards. Compotential threats. pleting this matrix with an interdisciplinary team will help all disciplines to think beyond a singular perspective. After developing a baseline understanding of stresses and threats, the design team and client should think about how threats would impact the client’s operations and response. Role-playing the identified hazard events can be an effective technique. In many cases, a narrative structure that begins with defining normal operations and then walking through the immediate and long-term problems posed by each event is useful to compile a list of effects and possible solutions. Consider studying groups of related hazards — such as short-duration weather events or events that would disrupt building power — to focus the discussion and draw out common solutions. Solutions may be a physical change in the facility design or organization or a change in operations.

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Abiding by the proverb: “a chain is no stronger than its weakest link” (attributed to Thomas Reed’s “Essays on the Intellectual Power of Man” from 1768), redundant mechanical equipment is useless if the structure collapses or the mechanical room is under water. Bringing all the disciplines together results in the best solution.

Location of engineered systems

Figure 2: With aging infrastructure, storm events can make roadways impassable and jeopardize building operations. With an interdisciplinary approach to anticipating these events, it is possible to minimize damage and maintain operations. Courtesy: SmithGroup

As these discussions generate scenarios and possible solutions, keep in mind that the goal is not to fully develop a set of formal strategies, but to gather ideas and to gain an understanding of the client’s values and resilience goals that will lead to documented strategies.

Evaluate resilient design strategies

After playing out various scenarios, the design team can develop a threat assessment matrix to include possible responses and their associated costs. The matrix organizes potential strategies in a way that can reveal commonalities in solutions. This tool also provides the design team and the client with a method to assess the relationship between cost and probability of occurrence and can guide the client’s decision-making. During this process, developing a menu of alternative solutions will help the client evaluate cost for the desired outcomes. Resilient design should not be approached as an “all-or-nothing” binary response. Rather, the menu of strategies can provide a range from simple, low-cost solutions to address a single aspect of disruption to complex solutions that bear a greater upfront cost, and ensure higher levels of operation throughout a hazard event. In between these two ends, the design team may find many different solutions that can be layered together to build a stronger, more resilient facility. A big-picture approach to designing resilient MEP systems is essential. Collaborate with architects and planners, civil engineers and landscape architects, structural engineers and fellow MEP and fire protection engineers to develop the best methods to achieve resilient design goals.

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The location of major MEP equipment that is part of a resilient system is the most important factor because it must be able to function in the face of local threats. Coordinate the location of major equipment early in the new building design process so that the architect can allocate space and integrate into the aesthetic vision from the beginning. Here are some considerations for locating equipment: • In regions prone to flooding, locate equipment above grade to prevent damage. For example, use pole-mounted electrical transformers. • In regions prone to tornadoes or hurricanes, locate equipment inside to avoid the vulnerability of equipment and to prevent equipment from becoming projectiles. For example, locate cooling towers inside the building and duct their intake and discharge to the outside. Another example is to locate emergency generators in a hardened location inside the building and locate the fueling system in an area that can be easily accessed during a hazard event. • Secure outdoor equipment to prevent damage from earthquakes, high winds or theft. For resilient design of MEP systems, the design team should identify the most critical systems for operations and any additional systems supporting the most critical ones. These are a few example considerations for designing reliable MEP systems with redundancy: • Heating is often more critical than cooling; however, cooling data closets is a highly critical function. • Local redundant systems serving different areas may better enable critical operations versus a central utility plant that could be incapacitated. • Power can be fed from multiple utility substations, so that if one goes down the building can still function. • Backup generators can be powered by diesel fuel in lieu of natural gas in case gas service is interrupted. www.csemag.com

CASE STUDY: • Power can be provided by off-grid solutions such as solar panels with battery storage if permitted by the authority having jurisdiction. • Multiple incoming water services from different water mains can provide redundancy if one of the pipe mains fails or is shut down for repairs. • Sanitary and storm drains can have multiple connections to different underground mains or on-site stormwater provisions can be made. • On-site potable water and waste storage can be provided so that the building can fully function for a limited time without connection to utility piping. Devising strategies for resilient design entails understanding the requirements of the owner and working with the local contractors and equipment manufacturers to understand system and equipment capabilities. Questions to ask for designing redundant systems include: • What are the critical systems requiring redundant backups? • What systems are necessary for others to function? For example, redundant boilers cannot function without power, therefore redundant power systems are required.

Designing for tornadoes in the Midwest

n 2019, Kansas City University began the design of its College of Dental Medicine in Joplin, Mo. With the town’s history of devastating tornadoes, including an EF5 event in 2011 that caused 158 deaths and $2.8 billion in damages, the university, its architects and its engineers worked together to address the vulnerability, operational needs and building solutions for the new facility. An evaluation of the existing campus showed that designing for continuous operations during a weather event would require extensive renovation of existing structures and systems, making that option unfeasible. Another option was to build a single-purpose shelter adjacent to the facility. The team determined that the best solution would be to provide enhanced life safety protection during high-wind storms incorporated into a space with day-to-day functions, creating a dual-use space. Together, the interdisciplinary design team worked with the client to role-play the daily operations and determine appropriate sizes and locations for the dual-use spaces. Architects and engineers teamed to design protective shelters for storm events as well as optimum useable space in the building for the day-today. This solution was the most cost-effective way to meet the client’s goals for resilient design.

• How much redundancy is suitable for the project? Is an N+1 design acceptable so that if one piece of equipment is out of service, the building can still function? • Do all systems need to function at 100% in a design hazard event? Can the redundant systems provide less function that maintains an acceptable level of operation?

Passive resilient design

Passive design that minimizes or eliminates reliance on power or mechanical systems is highly resilient. Examples of passive design strategies for enhanced resilience include: • Use of natural site features and low-impact site design to drain water by gravity, thereby eliminating pumps, backup pumps and power requirements. • High-performance building envelope to minimize heating and cooling requirements, reducing the need for redundant systems and emergency power.

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Figure 3: The Kansas City University College of Dental Medicine incorporates a shelter in the event of high-wind storms and coordinates the design with building systems to maintain continuity. SmithGroup is serving as a design architect and programming consultant, providing mechanical, electrical, plumbing, fire protection and structural engineering services for Helix Architecture + Design, the architect of record. Courtesy: SmithGroup consulting-specifying engineer

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• Operable windows to allow spaces to be habitable without air conditioning. • Ceiling fans to provide comfort with minimal power requirements. • High thermal mass building to reduce peak loads during cooling season and moderate indoor temperatures. Keys to resilient MEP design include having discussions with the interdisciplinary team early to ensure space is allocated, knowing which systems need to function at all times, understanding the level of redundancy that is desired and that the project budget can support and recognizing how all of the systems work together. This is a team effort that continues as the design evolves.

Preparing for disaster

COVID-19 is spurring people to act. We are taking responsibility for social well-being through social distancing and staying home. We are supporting front-line medical professionals by 3D printing personal protective equipment components.

Understanding a building’s resilient design levels

merican Society of Civil Engineers 41 Resilience Levels is an engineering standard that can be used to determine the level of resilience critical to maintaining or returning to everyday operations. Resilience levels are defined in terms of potential harm to occupants, initial extent of damage and time and cost to regain functionality. Life safety: Occupants inside are safe during a hazard event. The building loses functions and requires extensive repairs, leading to downtime while it is uninhabitable. After the event, occupants may be displaced for an extended period of time. This is the performance level embodied in the building code. Common examples: offices or residences. Immediate occupancy: In addition to protecting any occupants during a hazard event, the facility is able to return to full functionality within 48 hours. Repairs are minor and repair materials and labor are readily available. This level of resilience is typically employed for facilities that serve an important function, but that can tolerate short-term interruptions in service. Common examples: outpatient health care facilities, redundant utilities and first responder support facilities. Continuous operation: A facility designed for continuous operation during a hazard event has no loss of operations. This is an appropriate level of resilience for facilities whose loss of service would cause greater harm to the community. Common examples: major utilities, hospitals and data centers.

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As engineers and building design professionals, we are tasked with the protection of the health, safety and welfare of the public. We have the power to do more. We can lead the way in helping our communities and institutions prepare for disaster before it strikes. We can design systems and buildings to withstand catastrophe and adapt to the next hazard event, from designing hospitals to convert more rooms into intensive care in a pandemic, to preparing for record-breaking storms. By collaborating with architects, planners, civil engineers and landscape architects, we can collectively shape our built environment to be adaptive and resilient to the threats from Mother Nature. We can prepare not only for what we know to exist, but for anticipated changes in the future and the disruptions that we hope never to occur. The result: stronger communities, fewer lives lost and reduced risk of capital losses. Now is the perfect time to talk about disaster preparedness and designing for resilience. Use the tools and strategies outlined here as a guide to leading clients and peers to adaptive, resilient design solutions. cse Nancy Kohout is a principal and mechanical engineer at SmithGroup. She leads SmithGroup’s Chicago office mechanical engineering discipline with more than 20 years of experience and currently serves as the co-chair of Women in ASHRAE – Illinois Chapter. John Rushing is a structural engineer at SmithGroup. Rushing has more than 20 years of experience in structural design. Bill Wood is a civil engineer at SmithGroup. He has extensive expertise integrating infrastructure with placemaking design to provide resilient solutions and routinely speaks about green infrastructure and resiliency at regional conferences. Valerie Berstene is an architect and urban designer focused on resiliency and equity in communities.

M More SOLUTIONS

Additional resources: • Climate Central • Department of Housing and Urban Development Community Development Block Grant Disaster Recovery • Environmental Protection Agency Drinking and Wastewater Resilience • Federal Emergency Management Administration • RELi Rating Guidelines for Design and Construction • States at Risk • U.S. Climate Resilience Toolkit www.csemag.com

ENGINEERING INSIGHTS

MEP ROUNDTABLE

Students, tech, COVID drive higher ed design College and university building design is being driven by student needs, technology and new air quality demands CSE: What’s the biggest trend in college and university buildings? Kristie Tiller: Due to COVID-19, the biggest trend in college buildings right now is indoor air quality considerations. These considerations include enhanced filtration, disinfection technology and increase in air changes per hour. Tom Syvertsen: Energy efficiency has been the trend for a long time, but now, in light of current circumstances, occupant wellness is the current focus. Many temporary or even permanent, modifications to promote wellness greatly impact energy-saving strategies, but are being deemed more important, at least for now. We are also seeing open, collaborative, flexible spaces that can be used in a variety of ways. This trend leads to different design challenges in terms of providing the appropriate heating, ventilation and air conditioning or connectivity solution (electrical, information technology, etc.). We have also seen concerns over utility requirements for future growth and flexibility. This trend requires us to not only look at the owner’s current program, but to have discussions with faculty concerning what types of programs they envision over the next five to 10 years. Randy C. Twedt: The incoming generations of students grew up in technology-rich environments where they often exert a lot of control regarding how they experience space. They expect the same level of integration and control in the academic environment. They want to customize their experiences in terms of lighting and temperature, and they demand access to high-speed internet at all times. Thus, the systems increasingly need to provide technology-rich, cuswww.csemag.com

tomizable environments and also allow management to override customization to control for efficiency. Casimir Zalewski: Every higher education project seems to be looking for a collaboration or gathering space. These spaces typically see individuals connected to social media, websites or groups of people who want to share a story or discuss what they’ve learned or know. In any instance, the theme is that people are looking for a comfortable space where they can connect. That connection can be virtual or physical, but the space needs to exist. It needs to be comfortable, it needs power, it needs Wi-Fi and there is typically a desire for close proximity to some type of food or beverage. In short, the biggest trend is to

create a space that is familiar and comfortable to the occupants where they can make a connection. Patrick McCafferty: Arup has seen education clients around the world respond similarly to the COVID-19 pandemic. Schools everywhere are working tirelessly to implement safety measures as quickly as possible in preparation for reopening as soon as possible. A critical component of reducing transmission risk is de-densifying classrooms and residence halls, but doing so has put new constraints on the number of students campuses can accommodate. This has forced many higher education institutions to adopt a hybrid teaching model that combines in-person and remote learning.

Patrick McCafferty, PE, LEED AP,

Kristie Tiller, PE, LEED AP,

Associate Principal and Education Business Leader, Arup, Boston

Associate, Team Leader, Lockwood Andrews & Newnam Inc. (LAN), Dallas

James Michael Parrish, PE,

Randy C. Twedt, PE, LEED AP,

Associate Vice President, Department Manager Electrical, Lighting, Technology, Dewberry, Peoria, Ill.

Associate Principal/ Senior Mechanical Engineer, Page, Austin, Texas

Tom Syvertsen, PE, LEED AP,

Casimir Zalewski, PE, LEED AP, CPD,

Project Manager, Associate, Mueller Associates, Linthicum, Md.

Principal, Stantec, Berkley, Mich.

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James Michael Parrish: Flexibility, technology and energy efficiency. We’re seeing a need for mobile furniture, less static room and multiple monitors on walls, which allow for students to create “groups.” Additionally, facilities should be designed and constructed with the intention of being maintained over the course of many decades. CSE: Looking ahead, how do you think these buildings will be designed differently to meet new health challenges brought on by COVID-19?

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James Michael Parrish: We expect to see more distancing, restricted personnel, more attention to ventilation and germ-killing systems, such as ultraviolet. Perhaps more voice command systems to eliminate touch, but this is just integrating product development. Tom Syvertsen: At the project outset, the design team should encourage a meeting with the owner to discuss potential opportunities to implement strategies described in the ASHRAE Position Document on Infectious Aerosols. Some HVAC strategies have an impact on the architectural design and on energy consumption, so the HVAC engineer cannot make all the decisions regarding implementation of COVID-19 strategies unilaterally. It must be an integrated design process. Examples of design features include air handling units with increased ventilation, which also increases energy consumption. The AHU control strategy can incorporate a pandemic mode

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Some HVAC strategies have an impact on the architectural design and on energy consumption, so the HVAC engineer cannot make all the decisions regarding implementation of COVID-19 strategies

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SCAN & LEARN:

unilaterally. —Tom Syvertsen 50

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REASON

Figure 1: LAN supported the Alamo Colleges District’s capital improvement planning, including ongoing assessment services at all of the district’s campuses and recommendations for facility repair and replacement projects. Courtesy: LAN

that deploys only when the owner deems it necessary based on threat level and risk assessment. Features may also include AHUs with enhanced filtration and/or ultraviolet germicidal irradiation lamps. Both of these options will increase energy consumption, however. Lamp replacement costs will also increase. However, if placed in such a way that the UVGI performs cooling coil cleaning in addition to air stream disinfection, there can be some energy and maintenance savings, as the cooling coil partially offsets the added costs. We can also design HVAC systems that incorporate humidification. This will also increase energy consumption and maintenance costs and requires architectural evaluation. In general, we will be adding in much more flexibility to our systems and buildings. This means adding different building automation control modes and additional space in equipment for future modifications. We will be focusing more on IAQ and air distribution. Casimir Zalewski: Many energy saving features in buildings included reducing ventilation levels, total airflow or turning off equipment as soon as possible. Lights are also typically shut down as soon as possible. Room temperature and humidity are typically reset to save energy, if humification is designed or provided. While there is still much to learn about COVID-19, many of these energy saving features defy many current beliefs on what is best for occupants. I believe there will be more scrutiny on the importance of ventilation and filtration rates, the hours of operation of central equipment, passive disinfection solutions such as certain lighting sources and if future buildings will be designed to support humidification. Patrick McCafferty: While it is still early to predict, we expect to see emerging trends in the adaptive reuse of existing buildings; a greater emphasis on digital solutions and campuswide digital master-planning initiatives; an increased focus on smart building technologies; accelerated adoption of online teaching technologies, involving enhanced audiovisual/IT capabilities and cybersecurity provisions; and the creation of flexible and adaptable buildings able to accommodate myriad configurations and uses. Moreover, universities are likely to focus their attention on the buildings and infrastructure they already have — maximizing the space potential of their existing consulting-specifying engineer

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Up to 12% more efficient. R-32 systems are up to 12% more efficient than similar R-410A systems.

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ENGINEERING INSIGHTS

MEP ROUNDTABLE

Figure 2: Dewberry provided architecture, interiors, civil, structural, security/ technology and mechanical, electrical and plumbing services on the Bradley University Business and Engineering Convergence Center project, which unites the Caterpillar Colleges of Engineering and Technology and the Foster College of Business Administration to cross-train students in business and engineering. Courtesy: Dewberry

assets before embarking on new-build alternatives. More specifically, we expect to see less demand for large lecture halls and other spaces designed to accommodate crowds in the future due to the shift to online and small group learning models, as well as the drop off in international enrollment triggered by governmental travel restrictions. CSE: To help reduce COVID-19 transmission, what types of engineering solutions are you offering colleges and universities? Patrick McCafferty: When it comes to containing the spread of the novel coronavirus indoors, maintaining high levels of air quality and air flow is critical. Essentially, the higher your HVAC system’s performance, the lower your risk of spreading the virus. Ideally, we could redesign all education buildings to be

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more resilient to viral outbreaks. Instead, we have to look at the specific constraints of each building and its systems, as well as code requirements and then reverse engineer the system to boost performance as much as possible. Arup’s HVAC experts are working with a number of clients to institute measures to build their immunity to COVID. The changes being made are all aligned with ASHRAE’s COVID-19 prevention measures, but the mix of technologies used and the way they are applied tends to differ significantly from project to project. When it comes to HVAC risk reduction measures, there really is no one size fits all solution. We are also actively researching and developing computer models to help our clients determine how to integrate UVGI technology into their spaces for maximum impact. James Michael Parrish: Review of ventilation rates and consideration for

consulting-specifying engineer

UV lighting. We’re also assisting clients with technology applications such as thermographic cameras for temperature screening. Kristie Tiller: HVAC systems play a big role in the transmission of airborne diseases. Improvements to these systems we can expect to see are increases in outside air, increased ventilation and increased filtration. These are longterm solutions that will likely have an economic impact to the owner. College and university facilities, which are typically occupied during the day and stagnant at night, will start seeing an increase in energy usage because the systems will need to be flushed during off-peak hours to make sure the air is as clean as possible during peak hours. For several years, we have focused on energy-efficient systems and cost reduction. I expect a shift in this mentality and overall importance will be placed on effective systems. Tom Syvertsen: There are many industry-acceptable strategies for reducing the likelihood of COVID-19 transmission, but the most popular ones we have recommended to our higher education clients relate to increased filtration, increased ventilation, proper control of relative humidity and the addition of UVGI lighting of ample intensity in the recirculated airstreams. Randy C. Twedt: Educating academic clients about the benefits of technology remains a challenge. Many of these institutions may have outdated design guidelines and can be slow to adapt to change. How are college and university buildings being designed to be more energy efficient? Tom Syvertsen: Part of integrated design is working as a team to limit the heating and cooling loads at the outset of the project, whether that involves building orientation and fenestration, exterior shading, high-performance envelope materials, energy-efficient lighting and controls, energy-efficient equipment within buildings or other such measures. The best way to save heating and cooling energy is to reduce the amount of heating and cooling the building needs in the first place and then layer in the high-efficiency systems to condition the spaces. Casimir Zalewski: Today, there is a much better understanding of sustainwww.csemag.com

REASON

‘

College and university facilities, which are typically occupied during the day and stagnant at night, will start seeing an increase in energy usage because the systems will need to be flushed during off-peak hours. —Kristie Tiller

’

able practices and many integrated design firms have engineers included in the design from the very earliest phases. During programming and conceptual design phases, we’re seeing more focus on building siting and massing to optimize the building before any systems are even selected. Thermal massing, daylighting studies, comparative heating and cooling load analysis and energy models further refine the early building design. Careful review and analysis of envelope materials and joining methods along with field testing and quality control have greatly reduced building energy losses. Today’s codes mandate more sophisticated control systems that continuingly monitor the building and reset, reduce and turn off systems and equipment where possible. Increased involvement of third-party commissioning agents has also helped reduced energy usage through functional testing and control algorithm verification. Patrick McCafferty: In recent years, Arup has seen university campuses around the country make a concerted effort to walk the talk when it comes to sustainability. Many of our higher education clients have made significant investments in sustainable campus projects, spanning from high performance buildings to campuswide masterplans. We are also seeing more colleges and universities setting ambitious carbon neutrality goals and moving away from a reliance on traditional fossil fuels. Given the growing awareness of the urgency of climate action, we fully expect this trend to continue — in part because the next generation of students is beginning to demand action. We anticipate that forward-thinking higher education institutions will use this time of transition to transform and commit themselves to a new and much more sustainable future. Kristie Tiller: Typically, there is huge energy savings based on proper scheduling for HVAC and lighting systems during unoccupied times. With the new measures being taken to prevent spread of airborne diseases, much of this energy savings is lost with buildings needing to be flushed during unoccupied times. The balance between energy savings and providing the cleanest air to building occupants as much as possible can be extremely delicate. Randy C. Twedt: We are seeing more centralized systems that allow for user flexibility but also provide management override to ensure sustainability and performance goals are met. University of Texas at Austin is a unique example in that it is self-sufficient and relies on central utility plants for all power, cooling and water throughout the campus. CSE: How are engineers designing these kinds of projects to keep costs down while offering appealing features, complying with relevant codes and meeting client needs? consulting-specifying engineer

October 2020

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Widely available.

R-32 refrigerant is widely available from multiple manufacturers.

T H I S I S J U S T O N E O F 3 2 G R E AT R E A S O N S TO C H O O S E R -3 2 R E F R I G E R A N T. S E E T H E M A L L AT R 3 2 R E A S O N S . C O M .

WITH MORE THAN 100 MILLION UNITS INSTALLED WORLDWIDE, R-32 IS ENDORSED BY:

input #6 at www.csemag.com/information

SAFE, CONVENIENT

CORD DROP DISCONNECTS FROM MELTRIC MELTRIC Switch-Rated devices combine a plug, receptacle, and safety switch in one device. They make ideal cord-drop connections for welding machines, motors, pumps and other equipment.

• UL/CSA rated for branch circuit and motor circuit disconnect switching • Safely make and break connections under full load • Dead-front eliminates potential exposure to live parts and arcing • Meets NFPA 70E requirements without cumbersome PPE • Avoids the hassles of operating busway switches • Optional finger drawplates make connection easy

BEF

20-200 A, 600VAC, 100 HP, Type 4X and IP69K

YO U

meltric.com/sample

input #7 at www.csemag.com/information

ENGINEERING INSIGHTS

REASON

MEP ROUNDTABLE

Tom Syvertsen: We often perform life cycle cost analysis at the onset of a project to compare different systems and select the one that is most cost effective and the best fit for the owner. When cost estimates exceed budgets, we actively work to design changes that can save costs without any sacrifice to quality or performance. Many of our projects receive state or local funding. For example, in the Commonwealth of Virginia, all state-funded higher education programs must follow the guidance of the Division of Engineering and Buildings and their Construction and Professional Services Manual. The manual requires a full LCCA of at least three systems by the completion of preliminary design. Randy C. Twedt: We’re helping our academic clients develop new standards, reduce costs and provide customizable environments for the students. It’s important to perform energy studies and LCCA for various features to evaluate the correct systems for a client’s project budget. Because many of innovative features can cross multiple disciplines, these types of studies are evaluated early in the project design phase to ensure the design team is taking a holistic approach. Casimir Zalewski: Innovative projects have a need that may focus on a particular technology or operation. In industry, there are many products and design solutions that may meet the client’s need, but every region is different from the technology’s representation and acceptance as well as the local trade professionals understanding and exposure to a specific innovative technology. More and more, design teams are collaborating earlier with construction managers and trade professionals to better understand any concerns or opportunities on applying a certain innovation. Engineers act as a bridge between many groups to help achieve innovation by finding the technology the closest meets the client’s desired features while balancing the trade professionals’ comfort with the technology’s installation and availability to keep cost in check. Kristie Tiller: The best way is to work very closely with the owner and end users of the spaces we’re designing. While this doesn’t reduce the cost of the systems and equipment being put into the space, we are more quickly able to identify exactly what our clients need, therefore saving them money during the design process and eliminating change orders during construction. cse

M More

R-32 systems can reduce refrigerant carbon footprint by up to 80% as compared to R-410A.

T H I S I S J U S T O N E O F 3 2 G R E AT R E A S O N S TO C H O O S E R -3 2 R E F R I G E R A N T. S E E T H E M A L L AT R 3 2 R E A S O N S . C O M .

ROUNDTABLE

GO ONLINE

Read more at www.csemag.com about: • Automation and controls. • Codes and standards. • Electrical, power and lighting. • Fire and life safety. • HVAC and sustainability. consulting-specifying engineer

Low refrigerant carbon footprint.

WITH MORE THAN 100 MILLION UNITS INSTALLED WORLDWIDE, R-32 IS ENDORSED BY:

October 2020

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input #8 at www.csemag.com/information

Statement of Ownership, Management and Circulation 1. 2. 3. 4. 5. 6. 7.

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13 12,415 0 0 0 191 0 191 12,606 162 12,768 98.48%

12 10,062 0 0 0 200 0 200 10,262 122 10,384 98.05%

16. Electronic Copy Circulation

Input #100 at www.csemag.com/information

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Ease of Installation & NFC Enabled Commissioning

Belimo Room Sensors The Foundation of Comfort

The new Belimo room sensors are the perfect addition to Belimo’s existing duct, pipe and outdoor sensor range. The Belimo Assistant App enables simple, fast programming, commissioning and troubleshooting using NFC via a smartphone. In addition, the simple, user friendly design ensures the sensors ﬁt seamlessly into any room, for ultimate room comfort.

input #9 at www.csemag.com/information

Publication Services Jim Langhenry, Co-Founder and Publisher, CFE Media JLanghenry@CFEMedia.com Steve Rourke, Co-Founder, CFE Media SRourke@CFEMedia.com McKenzie Burns, Marketing-Events Manager MBurns@cfemedia.com Courtney Murphy, Marketing and Events Manager CMurphy@cfemedia.com Paul Brouch, Director of Operations 630-571-4070 x2208, PBrouch@CFEMedia.com

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consulting-specifying engineer

PM October 2020 2/9/2017 • 2:25:34 C3

ARE YOU STILL DESIGNING & SPECIFYING ELECTRICAL DUCT BANK?

THERE IS A BETTER WAY!

CABLEBUS

Image courtesy of MTA Capital Construction

SYSTEM

PROVIDES FREE AIR RATING BELOW GRADE!

•

Patented venting system achieves maximum cable ampacity based on Free Air Ratings.

•

Engineered to carry phase current loads up to 8000 Amps in a voltage range of 480V to 46kV.

•

Requires considerably less space and installation labor when compared to duct bank.

•

Smaller and unarmored power cables enable easier routing options and provide cost savings.

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Continuous conductors from source to destination are impervious to moisture and the elements.

•

Modular & Expandable system supports re-entry for future upgrades.

US Pat. 10,141,731 B2

2019 ®

To learn more, visit: www.MaxiampUnderground.com or contact us at sales@unitedwc.com or 1-800-265-8697 Celebrating 35 years in business input #10 at www.csemag.com/information