HVAC & Plumbing

The Wilshire Grand Center 73-story glass-and-steel skyscraper stands in the footprint of the old Hotel Statler, later known as the Wilshire Grand, in Los Angeles. Photo: Wilshire Grand Center

L.A.’s Wilshire Grand Center Stands Tall High-effi ciency Bell & Gossett and A-C Fire HVAC and fi reprotection systems help achieve sustainability and safety goals.

When the Hotel Statler opened in downtown Los Angeles in 1952, it was the largest post-Depression construction project in the United States. One of the major features of the $25-million project was that its 13 stories were “entirely air conditioned”—the pinnacle of a modern hotel in the early ’50s.

The Hotel Statler, later known as the Wilshire Grand, would become an L.A. cultural icon, hosting celebrities, politicians, and businesspeople from all over the world. Yet, over time, its heating and cooling systems became so inefficient that not even a $20-million makeover could save the aging hotel, setting in motion the 5-yr. construction of a new hotel, offices, and retail space.

A 73-story glass-and-steel skyscraper now stands in the footprint of the old hotel, its distinctive rooftop spire making it the tallest building west of Chicago. The $1.35-billion Wilshire Grand Center opened in 2017 to international acclaim for its sophistication and luxury, a skyline-changing icon of modern design and a catalyst for L.A.’s economic rebirth.

The Wilshire Grand Center is also notable for achieving new levels of safety and sustainability, from its reinforced concrete core for earthquake and fire protection, to its radiant heating and cooling systems that use a fraction of the energy of a forced-air system.

“The interdisciplinary collaboration among engineers, architects, mechanical contractors, and others in the design-build process is resulting in new commercial buildings that maximize technology to better use materials and energy to improve the health and safety of occupants. Keeping costs in line and preserving resources for the future are intertwined in the process,” said Mark Handzel, vice president, Product Regulatory Affairs, and director, HVAC/Commercial Building Services Americas, Xylem AWS, Rye Brook, NY (xylem.com). “When you consider that half of the residential and commercial buildings that will exist in the United States in 2030 have yet to be built, the importance of this type of cooperation increases exponentially.”

HIGH-EFFICIENCY HVAC Effi cient use of energy within buildings is a primary focus of industry guidelines, such as ASHRAE 90.1, that have a direct impact on HVAC-system design and installation. In addition, California’s Title 24 is a set of energyeffi ciency rules that govern new-building construction to improve water effi ciency, along with effi ciency standards for mechanical systems.

The Wilshire Grand Center design team, led by AC Martin Architects, Los Angeles (acmartin.com), worked with energy consultant Glumac, Los Angeles (glumac. com), to perform extensive energy modeling to design the glass façade, which informed the design of the HVAC and lighting systems—the two biggest energy users within a building.

With an HVAC system accounting for as much as

50% of a commercial building’s energy cifically for commercial hydronic sysuse, designing efficient heating and cooltems, provide radiant floor heating and ing systems was critical to meeting the cooling in the ground-floor lobby and in project’s sustainability goals. sky lobbies.

Working with AC Martin and the general contractor, Turner Construction Co., A-C FIRE PUMP’S PLAN Los Angeles (turnerconstruction.com), From the rooftop’s open-air plaza on ACCO Engineered Systems, Los Angeles the 73rd floor, the views extend to the (accoes.com), completed the design of the southern California coast 50 miles out. hydronic HVAC system that would The roof design is one of the most talkachieve LEED-Gold status. The HVAC ed-about features of the building, breaksystem features a central plant with ing with L.A.’s traditionally flat-roofed high-efficiency chillers and condensing skyscrapers that are required to have boilers that supply chilled and hot water to helipads by city code. Wilshire Grand the 2.1-million-sq.-ft. building. architects obtained an exemption from

Relying on its longstanding relationthis 1970s rule, reportedly because of the ship with Dawson Co., Pomona, CA (dawaddition of other fire-safety features that sonco.com), a Bell & Gossett manufacturwould exceed the city’s fire-code requireer’s representative, ACCO specified Bell & ments, such as the reinforced concrete Gossett, Morton Grove, IL (bellgossett. central core that contains a staircase solecom), pumps and products for the ly for the use of firefighters in the event Wilshire Grand’s HVAC system. of an emergency.

“A major challenge on the project was Stringent L.A. and California buildthat construction had to begin prior to ing codes for fire safety and the NFPA 20 completion of the design—and the budget Standard for the Installation of Stationwas already set,” said John Boncich, senior ary Pumps for Fire Protection—as well as vice president, ACCO Engineered Sysproject parameters—drove the design tems. “We knew support from the Dawson process. and Bell & Gossett teams would be im“One of the challenges was to design portant from a technical standpoint and a system that met the city of L.A.’s realso in meeting critical milestone dates.” quirement that total pressure shutoff can’t exceed 600 psi,” said Brian Buscher, BELL & GOSSETT’S ROLE global product manager—fire protection, The 1,100-ft.-tall building is anchored by a Xylem AWS. “Our A-C Fire Pump disseven-level podium structure that houses tributor, Starfire Inc., [Anaheim, CA, retail establishments, restaurants, meeting starfireusa.com], worked closely with rooms, ballrooms, and a swimming pool. sprinkler contractor XL Fire Protection On top of the podium is 400,000 sq. ft. of The Wilshire Grand Center is notable for achieving new levels of safety and sustainability, from its reinforced con[Santa Ana, CA, xlfireprotection.com] office space. crete core for earthquake and fire protection, to its radiant heating and cooling systems that use a fraction of the on the design.”

Bell & Gossett’s 300-psig working presenergy of a forced-air system. Photo: Gary Leonard/Wilshire Grand Center Brian Callahan, president of XL Fire sure VSX and e-1510 pumps supply chilled Protection, is an accredited Certified and hot water to the podium and office heat exchangers isolate the building’s pressure zones Fire Protection Specialist (CFPS) by levels, and standard-working-pressure VSX pumps serve from each other. NFPA, and level 4 certified NICET designer. He sketched the thermal-energy-storage system that is located on the Other Bell & Gossett equipment that was used in the a two-zone system that met the highrise requirements, podium’s second level. The energy storage system charges HVAC system includes air separators and expansion worked within the space restraints of the fire pump room, a water tank overnight to reduce the number of chillers tanks that function to increase and decrease pressures in and did not exceed maximum pressure requirements. that are needed to operate the building during daytime the hydronic system in response to any changes in build“One pump services the low zone, but the high-zone hours. ing temperature. portion requires two pumps in series to create the 600 psi

“Besides the versatility and robustness, the VSX The Intercontinental Los Angeles Downtown hotel, that was required. Once I knew the flow and pressure rebrings to a high-efficiency hydronic system, it’s easily serwith about 900 rooms on floors 31 to 66, a 70th-floor sky quirements, I was able to select the right combination of viceable, and its compact design takes up less space in the lobby, and bars and restaurants on floors 69 and 71, occupumps to achieve that result,” stated Starfire’s Bennett. pump room,” said Manual Masso, Dawson Co. vice prespy the building’s tower structure. Inside the mechanical A-C Fire Pump vertical-turbine pumps and A-C Fire ident of commercial sales. “Decreasing the size of meroom on the 30th floor, 300-psig VSX pumps provide Pump 8200 series horizontal split-case pumps were selectchanical rooms means more saleable space, and that’s a climate comfort to the hotel guest rooms using four-pipe ed for the job. Codes require an exact set of redundant priority in all commercial building projects.” fan-coil units and air handlers. fire pumps on each level, so that meant six fire pumps in

Bell & Gossett AHRI 400 certified plate-and-frame Bell & Gossett series e-90 inline pumps, designed spetotal. “By getting the number of pumps down to six,

L.A.’s traditionally fl at-roofed skyscrapers are required to have helipads by city code, but the Wilshire Grand architects obtained an exemption reportedly because of the addition of other fi re-safety features that would exceed the city’s fi recode requirements. Photo: Gary Leonard/ Wilshire Grand Center

there was no need for an additional emergency generator, saving project cost,” Callahan explained.

Once the design was conceived, the team had to be sure the system would work as planned. “We had to do a lot of sizing and theoretical planning on what the pump curves would look like, especially in the high zone where the vertical turbines pump into the split-case pumps and were approaching 600 psi,” Bennett said.

That also becomes more complicated because of NFPA 20 requirements for fire-pump impellers, which state the pressure at shutoff cannot exceed 140% of the rated pressure at the rated flow and can’t be below 65% at 150% of the rated flow.

“One of the things we look at is not just the design-point flow and head-system needs, but also what the pressure is on the pump when it is at churn. We have to design the impeller to limit that pressure so that it is not over pressurizing the system components downstream of the pump,” Buscher said. Even at shutoff, the static pressure in the turbine pumps was 77 psi, which required a pressure-reducing valve on the standpipe systems. “Controlling the pressure was our biggest challenge,” Callahan said.

The Wilshire Grand fire-protection system design is also unique in the low-zone pump room, with the vertical turbines sitting atop a 120,000-gal. three-story water tank in the second of five basement levels—with space at a premium on the site, there was no room for it outside the building. Designers had to be sure this setup would meet the NFPA 20 requirement on how tanks are constructed and that the fire pump would be capable of providing demand for the whole building in an emergency.

BEYOND THE BUILD In a project the size and scope of the Wilshire Grand Center, adhering to the timeline is vital to the project’s success. The construction site posed additional challenges—at just 2.8 acres, the site offered no space to store materials.

“A 73-story building takes years to build, so project coordination in regard to product lead times and deliveries had to be in line with the construction schedule,” Masso said. “Deliveries were lifted by cranes to the floors when they were needed.”

Once HVAC and fire-protection systems were in place, the next steps were to test the systems and train building personnel on their operation. On the fire-protection side, the fire-pump acceptance test was an essential step in obtaining the occupancy permit for the building. In testing the equipment, there was some fine-tuning in the time between turning on the pump and it feeding into the split-case pump. By adjusting sequencing with the fire-pump controller, the team was able to close the gap from 10 to 15 sec. at startup to just 7 sec. The system also met the challenge of the 600-psi requirement.

“In the end, everything worked as designed,” Callahan said. “It’s not just putting in products; everything had to perform properly as a system and meet code.”

On the HVAC side, Dawson Co. representatives conducted equipment training for maintenance and other personnel on the 18 Bell & Gossett products prior to the building opening.

With nearly two-dozen skyscrapers being built in the City of Los Angeles, the Wilshire Grand Center likely won’t be the tallest building in L.A. for long. However, from its roots as a pinnacle of modern design, it stands tall as a symbol of the new way of thinking about commercial building, using an integrated-design approach involving the fields of architecture, engineering, and construction to achieve safety, efficiency, and sustainability goals. CA

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