a) Site Selection and Planning--The optimal site is an open site
near the crest of a southfacing hill with a minimum of five building heights
between buildings. Avoid solid enclosure walls or fences nearby that might
b) Building Shape--Buildings shall be elongated along the
east-west axis, with the long faces to the south and north, elevated on
columns or north-south walls.
c) Landscaping--Nearby ground surfaces should be covered with
grass rather than asphalt. Trees and hedges that shade the ground, building
surfaces, open outdoor areas, and parking lots should be selected.
d) Building Envelope--Design should provide for adequate
insulation and shading to minimize internal heat gains from solar radiation.
Large openings in positive and negative pressure zones shall be on the north
and south walls for ventilation. If insect screens are necessary, they shall
be placed at the balcony walls rather than directly over the windows, to
increase the screen area and reduce its resistance to incoming airflow.
e) Interior Planning--For maximum ventilation, the building should
be planned with a single loaded corridor and minimal interior partitions in
the naturally ventilated rooms. Separate ventilation of odor, heat or
humidity producing spaces such as bathrooms should be provided and these
spaces should be placed on the lee side of the building. Provide ceiling fans
in all major occupied spaces for use when outside wind speeds are too low.
Analysis and Testing Procedure. Every building design shall be
evaluated to determine if the required comfort levels are achieved. When
evaluating the quality of ventilation from a human comfort standpoint, it is
important to consider the interior air distribution as well as the total
amount of airflow. One or more of the following five analysis methods
(188.8.131.52 through 184.108.40.206) shall be undertaken as early in the design process
as possible to facilitate any necessary design changes.
Method 1. Perform the window sizing procedure (Appendix C, para.
1.2) for the worst two naturally ventilated months. If the proposed building
design meets or exceeds the required window square footage, then acceptable
levels of comfort can be expected.
Method 2. The ASHRAE formulae may be used to determine interior
air movement rates in relatively simple buildings. Refer to Appendix C, para.
1.2 for formulae and description. Examine the two worst naturally ventilated
months. If the proposed building design achieves greater or equal air
movement than that required from the climate analysis, (Appendix B), then
acceptable comfort levels can be expected.
Method 3. For complex building shapes or buildings taller than six
stories, use a wind tunnel test to obtain direct interior velocity
sizing method. Refer to Appendix C, para. 1.3 for wind tunnel test
procedures. For buildings that are complex or house critically important
functions, computer analysis using a typical hourly weather tape to estimate
indoor thermal conditions is also recommended.