redirect breezes into the building. On sloping sites, locations near the
crest of the hill on the windward side are desirable. Valley bottoms should
be avoided since they may have reduced air movement.
Street layouts can be used to channel airflow in higher density
site planning. If buildings are grouped, airflow principles should be used to
determine the most suitable arrangement.
Minimize unshaded paving to reduce the amount of solar heat
absorbed and stored near the building. Organic ground covers are preferable to
manmade surfaces since they are able to reject solar heat by evaporation. For
a description and guidelines refer to paras. 4.2 and 4.3 and Appendix A,
Building Envelope and Structure. The roof and walls exposed to the
sun shall be well-insulated to keep solar gains to a minimum. Light colored,
reflective exterior surfaces shall be used. Solid outer walls shall be
reduced to a minimum to permit maximum ventilation. The roof becomes the
dominant building feature providing protection from the sun and rain. There
is an advantage to using lightweight envelopes that will not store daytime
heat into the evening hours.
The building envelope shall be designed and constructed to maximize
natural ventilation of the interior spaces. The building's orientation and
shape are important concerns. One- or two-room-deep plans elongated along the
east-west axis are preferable. Window placement, size, type, and position
will influence ventilation effectiveness. Elevating the building may also be
desirable (refer to Section 4).
Solar Shading. Shading of the glazing is required at all times of
the year when cooling is required (both natural and mechanical) from 8 am to 6
pm solar time (refer to Appendix B). The shading should be exterior to the
glazing to provide maximum protection from radiant solar heat gain. External
shading of building surfaces, outdoor living areas and parking lots is also
recommended. For a review of shading device types refer to para. 126.96.36.199.
If the proposed design does not meet these shading requirements,
the designer should provide heat gain/loss calculations to show that effective
solar control will be provided by alternative means and that thermal comfort
will be maintained. The solar gain values in para. 4.5 may be used for this
Thermal Insulation. The ceiling should be insulated if an attic is
required. Roofs above inhabited spaces, and walls exposed to direct sunlight
should also be insulated. For a description of requirements refer to para.
Interior Spaces. Interior occupied spaces shall be shaded and well
ventilated. Minimum interior walls, partitions and other obstructions to
airflow are desirable. Light, reflective colors are preferable. Heat,
moisture, and odor-producing areas should be separated from the rest of the
occupied spaces and separately ventilated (refer to para. 4.6).