3.7 LOUVERS
Location of ventilation louvers requires careful consideration of prevailing
winds, as well as close coordination between the architect and mechanical
engineer, to avoid the re-entry of exhaust air and the intake of exhaust
fumes form vehicles and other engines. See HVAC Design Manual, Paragraph 1.8,
"Location of Outside Air Intakes and Exhaust Air Outlets".
3.8 PARAPET WALLS, ROOF STRUCTURES, AND WALKWAYS
3.8.1 PARAPET WALLS
Masonry parapet walls are potential sources of water penetration, unequal
thermal expansion, additional structural loads, and increased costs.
Therefore, do not use such walls for any building unless specifically
permitted by the Project Manager. Proposed parapet walls must be justified by
aesthetic, functional or economic considerations. Where permitted, design and
reinforce them to assure stability and water tightness when subjected to
lateral or thermal forces.
3.8.2 ROOF STRUCTURES
Make roof structures, such as penthouses and architectural screens enclosing
or concealing roof-mounted mechanical equipment, compatible in appearance and
with the material, texture, color, and shape of the building. Where it is
necessary to expose roof-mounted mechanical equipment, minimize its
appearance by location, low silhouette, and color.
3.8.3 ROOF WALKWAYS
Provide roof walkways of prefabricated asphalt planks with non-slip surfaces
on access routes over roofs to mechanical equipment requiring recurrent
maintenance. Where necessary for safety of maintenance workers, provide
ladders, stairs and/or platforms. Show their locations and provide details on
architectural drawings.
3.8.4 ATTIC WALKWAYS
In attic spaces to have batt or loose floor insulation, provide walkways for
access to mechanical and electrical equipment. Show the location and details
of attic walkways on architectural drawings.
3.8.5 ROOFTOP GUARDRAILS
Whenever mechanical equipment requiring periodic maintenance is installed on
a roof more than 6 m (20 ft.) above the ground, provide guardrails or fences
between the roof edge and any equipment or walkways less than 3 m (10 ft.)
from the edge. Design the guardrails 1050 mm (42 in.) high and in accordance
with OSHA requirements for standard guardrails.
3.9 LOW-SLOPE ROOF SYSTEMS
3.9.1 GENERAL
3.9.1.1 Design low-slope roof systems in accordance with the recommendations
of the National Roofing Contractors Association (NRCA) Roofing and
Waterproofing Manual and this manual.
ARCHITECTURAL DESIGN MANUAL
3-7
BUILDING ENVELOPE
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