Hot and Humid Climate Zoning by Jeos Oreamuno

Hot and Humid Climate

Urban Residential Zone

JEOS OREAMUNO

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Urban Residential Zone Response to Hot and Humid Climate

Table of Contents

ARTICLE 1. Hot and Humid Climate 1.1 1.2 1.3 1.4

Climate Zones North America Heat Flow Thermal Criteria

ARTICLE 2. Building Envelope 2.1 2.2 2.3 2.4 2.5 2.6 2.7

Design Criteria Building Layout Building Orientation Building Elevation Building Openings Building Materials Urban Density

ARTICLE 3. Zoning Regulation 3.1 3.2 3.3 3.4 3.5 3.6

Stories Siting Lot Coverage Dwelling Units Setbacks Parking

ARTICLE 4. Sustainable Elements 4.1 4.2 4.3 4.4

Podium Ventilation Rainwater Harvesting Terrace Garden

ARTICLE 5. Design Standards 5.1 Zoning Table ARTICLE 6. Diagrams 6.1 Section Diagram 6.2 Plan Diagram 6.3 Axonometric

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 1. Hot and Humid Climate

1.1 Climate Zones Hot and Humid regions are divided into two categories; equatorial and tropical-marine regions. Both have similar temperature, humidity, and rainfall conditions but are different in their wind conditions. In coastal regions, the constant heating and cooling patterns of the sea and land areas create regular sea breezes, providing regular air motion and mitigating the heat stress, mainly during the afternoon hours. The tropical-marine region utilizes the trade winds blowing westward. The path of the trade winds moves north and south with the annual shift of the sun’s declination. In the equatorial regions precipitation is caused mainly by rising convection currents of moist air, resulting from the convergence of the trade winds at the equatorial zone, after passing over extensive ocean areas. This flow pattern leads in many areas to a regular pattern of afternoon rains, often accompanied by violent thunderstorms. 1.2 North American In North America tropical-marine climate affects the eastern half of Texas, Oklahoma, Louisiana, Arkansas, Alabama, Mississippi, North Carolina, South Carolina, Tennessee, Georgia, Kentucky, Florida, Virginia, and West Virginia. Humid subtropical climate can also be found in the Mid-Atlantic, primarily Maryland, Delaware, the District of Columbia, southeastern Pennsylvania, southern New Jersey and southern parts of New York, specifically New York City and parts of Long Island. Summers in this zone are hot and humid, with daily averages above 77°F with average daily maximums above 86°F. 1.3 Heat Flow Moisture flows from areas of greater concentration to areas of lesser concentration. Buildings experience heat gain from the environment in three principal ways. In convection, heat is exchanged between a fluid (typically air) and a solid, with air flow playing a critical role in the extent of heat transfer. In conduction, heat is transferred directly within or between materials, with material density playing a critical role in the extent of heat transfer. In radiation, heat flows via electromagnetic waves from hotter surfaces to cooler surfaces. Moisture flow through envelopes is the principal means of latent heat gain. 1.4 Thermal Criteria The U-Factor expresses the steady rate at which heat flows through a building envelope assembly and are commonly used in the built industry to specify envelope’s thermal design criteria. U-factors are calculated for a particular element (roof, wall, etc.) by finding the resistance of each material, including air space, then adding the resistances to obtain a total resistance. The U-factor is the reciprocal of the sum of the resistances. The result is an overall coefficient of heat transfer, and includes the effects of all sensible modes of heat transfer (conduction, convection, and radiation).

1. Humid SubTropical Climate °C

MONTHLY DIURNAL AVERAGES - Miami, Florida - USA LEGEND Comfort: Thermal Neutrality Direct Solar Diffuse Solar

W/m²

1.0k

0.8k

0.6k

0.4k

0.2k

-10

0.0k Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

2. Monthly Diurnal Averages W/m²

DIRECT SOLAR - Miami, Florida - USA

1st January to 31st December

W/m²

1.00k

0.80k

0.60k

0.40k

0.20k

0.00k

14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th 14th 28th Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

3. Direct Solar Radiation

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 2. Building Envelope

2.1 Design Criteria The design objectives should be to modify the indoor climate in order to improve the comfort of the inhabitants, reduce the energy consumption of the building for heating in winter and for cooling in summer, and minimize the dangers to life and property damage from tropical storms. Passive cooling systems and natural or fanned air ventilation are required solutions for climate control. 2.2 Building Layout A spread-out building with large operable windows enables better natural cross-ventilation. Once the building is cross-ventilated during the daytime hours its indoor temperature tends to follow the outdoor pattern. Shading devices which intercept direct solar radiation are less effective at minimizing the heat effect due to the level of water vapor in the air. 2.3 Building Orientation Natural ventilation, in reference to wind direction, should be the primary factor associated with building orientation. The eastern and western walls and windows receive, year-round, much more radiation than the northern and the southern walls. Hot-humid regions at low latitudes have winds mainly from the east (the trade winds belt), changing in a given north-south shift of the trade winds belt. 2.4 Building Elevation Hot-humid regions often experience floods. Raising the buildings on stilts reduces the likelihood that floods will reach the floor level. The land in hot-humid regions is often covered by vegetation, raising the building off the ground can improve greatly the potential of ventilation. The windows of singlestory buildings at the ground level are often located in the zone of restrictive wind speed, a factor which reduces the potential for cross-ventilation of the indoor space. 2.5 Building Openings Openings in a hot-humid climate play a major role in determining the thermal comfort of the occupants. Their location and size determine the ventilation conditions of the building. Large openings in all the walls can provide an effective cross-ventilation solution. However, solar radiation can penetrate directly though unshaded openings into the interior of the building and elevate the indoor temperature above that of the outdoor In low-latitude regions it is possible to provide shading for walls and openings facing north and south; in multistory buildings, by wide balconies extending along the whole faรงade. Eastern and western walls are subjected to the impact of the low sun. Fixed shading for the windows should therefore be capable of blocking the low sun rays in order to be effective.

4. Prevailing Winds 50 km/h 40 km/h 30 km/h 20 km/h

hrs 37+ 33 29 25 22 18 14 11 7 <3

10 km/h

40 km/h 30 km/h 20 km/h

hrs 42+ 37 33 29 25 21 16 12 8 <4

30 km/h 20 km/h

hrs 47+ 42 37 32 28 23 18 14 9 <4

September

Prevailing Winds Wind Frequency (Hrs)

50 km/h 40 km/h 30 km/h 20 km/h

50 km/h 40 km/h 30 km/h 20 km/h 10 km/h

October

50 km/h 40 km/h 30 km/h 20 km/h

50 km/h

hrs 71+ 63 56 49 42 35 28 21 14 <7

40 km/h 30 km/h 20 km/h

10 km/h

hrs 66+ 59 52 46 39 33 26 19 13 <6

50 km/h 40 km/h 30 km/h 20 km/h

April 50 km/h

hrs 43+ 38 34 30 25 21 17 12 8 <4

40 km/h 30 km/h 20 km/h

10 km/h

hrs

50 km/h 40 km/h 30 km/h 20 km/h

August hrs

50 km/h

51+ 45 40 35 30 25 20 15 10 <5

40 km/h 30 km/h 20 km/h

10 km/h

November

hrs 51+ 45 40 35 30 25 20 15 10 <5

10 km/h

July

49+ 44 39 34 29 24 19 14 9 <4

hrs 38+ 34 30 26 22 19 15 11 7 <3

10 km/h

March

June

10 km/h

5. Flood Zones

20 km/h

10 km/h

May

40 km/h

30 km/h

hrs 50+ 44 40 34 30 25 20 15 10 <5

February

10 km/h

50 km/h

40 km/h

10 km/h

January 50 km/h

50 km/h

10 km/h

December

6. House design by Touzet Studio

hrs 49+ 44 39 34 29 24 19 14 9 <4

Urban Residential Zone Response to Hot and Humid Climate

2.6 Building Materials The role of materials in hot and humid regions is to minimize solar heating of the interior during daytime and to maximize the rate of cooling during the evening and night hours. Lightweight materials such as wood construction are typical in hot and humid climates. Low heat capacity can enhance the rate of cooling of the building during the evening and night hours. The need for thermal resistance in a building is determined by the desired to minimize the elevation of the indoor radiant temperature, namely the temperature of the surfaces of the roof and the external walls, above the indoor air temperature. 2.7 Urban Density Urban density is among the major factors which determine the urban ventilation conditions, as well as the urban temperature. Under given circumstances, an urban area with a high density of buildings can experience poor ventilation and strong “heat island” effect. In hot-humid regions these features would lead to a high level of thermal stress of the inhabitants. Economic and social influx dictates that cities must become more concentrated, making it necessary to increase the density to reduce the cost of public services and achieve required social cohesiveness.

7. Wall Assembly

Component Inside air film Gypsum board (0.375 in) Plastic film vapor Retarder Glass fiber batt Insulation (6in) Plywood (0.5in) Wood sliding (1in) Outside air film Total resistance (R)

8. Direct Solar Radioation (W/m2) W/m²

R ( SI)

900+ 800 700 600 500 400 300 200 100 <0

0.12 0.056 nil 3.35 0.11 0.14 0.03 3.81

600

U (IͲP) = 1/∑ R = 1/3.81 = 0.262

400

200

8 12

4 0

Wk 4852 44 40 36 32 28 24

9. Visualizing Density

LESS THAN 1 UNIT PER ACRE

Beverly Hills, CA 0.2 units / acre

Hollister, CA 0.3 units / acre

Broomfield, CO 0.3 units / acre

context

neighborhood

plan

10. Density Classification

neighborhood

plan

neighborhood

plan

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 3. Zoning Regulation

3.1 Stories Stories are defined as the allowable amount of building levels per structure. Ground floor units can extend to a maximum height of 14 feet (4.23m) in response to commercial applications and crowd volumes. The rest of the floors have a maximum height of 10 feet (3.05m). Floors associate with mechanical systems and lifts may request variance. 3.2 Siting Siting structures on a parcel determines the relationship with the street as well as the impact associated with the orientation of the building. In an urban residential zone all ground level units are to rest on a 2’ (0.6m) podium. The podium functions both as a first defense system for flood control and an onsite stormwater filtration system. 3.3 Lot Coverage Lot Coverage is determined via parcel size. In an urban residential zone (T4) parcels less than 25’ (6.7m) are restricted to 45% coverage at ground level. Parcels greater than 25’ (6.7m) can cover 65% of the parcel at ground level. 3.4 Dwelling Units Dwelling Units (DU) for an urban residential zone are determined by parcel width. Parcels less than 25’ (6.7m) have a maximum of 1(DU), parcels between 25’-69’ (7.6m-21.0m) have a maximum of 6(DU), and parcels larger than 70’ (21.34m) have a maximum of 12(DU). Also, parcels less than 25’ (6.7m) are allowed an auxiliary unit detached from the primary unit. 3.5 Setbacks Setbacks site buildings to be consistent with intended character and functional requirements of the neighborhood. Setbacks also improve connection between varied uses and the public street. Crossventilation also benefits from multi-story setbacks. 3.6 Parking In order to maximize parking slots and minimize the visual impact of parking areas and curb cuts all residential parking is to be allocated behind ground floor commercial zones and accessed by the alleyways. Parking thoroughfares are to be shared by all owners in order to offer the maximum amount of parking slots on the grown floor.

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 4. Sustainable Elements

4.1 Podium Podiums are set back a minimum of 4’ (1.21m) from the lot line as a means to expand pedestrians’ right-of-way allotting space for a green belt which can house trees that will provide shade and help reduce the heat island effect. The podium functions both as a first defense system for flood control and an onsite stormwater filtration system. A layer consisting of a mixture of sand and gravel under the podium can increase the area of effective infiltration below the surface, thus increasing the rate of water absorption in the ground. 4.2 Ventilation A major factor determining the level of thermal stress in a hot and humid region is the potential for natural ventilation. Ventilation is the amount of air circulated through a space. Ventilation ensures that enough air is supplied for the number of occupants preventing accumulation of carbon dioxide and other pollutants in the space. 4.3 Rainwater Harvesting Rainwater harvesting is the accumulating and storing of rainwater for reuse. Rainwater collected from the roofs of buildings can make an important contribution energy use. The use and implementation of roof ponds has the potential to stabilize interior temperatures. Roof ponds sized for cooling will likely be nearly equal in area to the floors of the buildings they cool. Average pond depth is between 3 and 6 in (75 and 150 mm). 4.3 Terrace Vegetable Garden Terrace vegetable gardens are patios or balconies designed with an assortment of containers to grow vegetable plants or seeds. Low, upright vegetables are chosen to take advantage of structures and space to provide harvesting of food throughout the summer planting season. By designating a percentage of the parcel to food production, on the residential level, terrace vegetable gardens forester commitment to sustainable urban living.

“The key to shifting the building regulatory system towards greater acceptance of more sustainable, alternative approaches is to create a context in which those alternatives can be seen both as positive and as representing a reduction of risk, rather than an increase in risk… The larger, ecologically based risks to public welfare must eventually be seen as risks that demand responsibility for protecting public welfare as much as structural integrity, fire safety, or means of egress.” David Eisenberg

11. Ventilation Diagram

12. Rainwater Harvesting Systems

13. Retaining Bladders

14. Terrace Vegetable Garden

13. Roof Ponding Systems Diagram

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 5. Design Standards

5.1 Zoning Table

Height Stories

Main Street Lot Side Street Lot

Siting

Zone Lot Lot Coverge (Ground Level) Lot Width Dwelling Units per Primary Residential Structure (min/max) Auxiliary Dwelling Unit (min/max) Ground Residential limited to ADA accessible Units (min/max) Setbacks Main Street Ground Floor: 50% Frontage Second Floor: Third Floor: Setbacks Side Street Ground Floor: 40%Frontage 60%Frontage Second Floor: 20%Frontage 80%Frontage Third Floor: 40%Frontage 60%Frontage Setbacks Alley Ground Floor: Second Floor: Third Floor: At Side Ground Floor: Second Floor: Third Floor: Parking Shared surface Parking behind commercial

Sustainable Elements

Building Configuration All street level structures sits on a 2’min podium Ventilation: Residential units, Exception ADA accessible units Rainwater Storage Terrace Vegetable Garden

Type A

Type B

Type C

3 max 3 max

3 max 2 max

Type A

Type B

Type C

65% 70’+

45% 26’-69’

65% < 25’

8/12 0 0/2

3/6 0 0/2

1/1 0/1 0/1

8’ min 12’ min 14’ min 14’ min

8’ min --14’ min 14’ min

8’ min 12’ min 14’min 14’min

--14’ min 8’ min --8’ min 14’ min --14’ min 18’ min

8’ min ----8’ min -----------

4’ min 4’ min 4’ min

4’ min 4’ min ---

0’ min 2’ min 4’ min

0’ min 2’ min ---

Type A

Type B

Type C

2’ min 10’ above ground min Roof Pond 10% Lot

Urban Residential Zone Response to Hot and Humid Climate

ARTICLE 6. Diagrams

6.1 Section Diagram

6.2 Plan Diagram

6.3 Axonometric

Urban Residential Zone Response to Hot and Humid Climate

References Mckeegan, Noel “Rainwater storage solutions stays out of sight”. 26 June 2007. Web. 17 Apr 2011. http://www.gizmag.com/go/7519/

“Building and Urban Design For Hot-Humid Regions” Building and Urban Design Guidelines. Ch11. “Green Building and LEED Core Concepts” 2009 First Ed. USGBC

Stein, Benjamin, et al. 2006. Mechanical and Electrical Equipment for Buildings. New Jersey: John Wiley & Sons, Inc.

Eisenberg, David and Yost, Peter. 2001. “Sustainability and Buildings Codes” Environmental Buildings News, 10(9) 1 8-15

Wackernagel, Mathis and Rees, William. 1996. “What Is and Ecological Footprint?” Our Ecological Footprint.

Maclaren, W. Virginia. 1996. “Urban Sustainability Reporting” Journal of the American Planning Association