Areas
Room
Exhaust Air
Pressure
Air Changes/Hr
Waiting Rooms
Negative
SA + 15 Percent of SA
Notes:
(a) Exhaust air requirement can be waived and re-circulation air
permitted, only if the air circulation is confined to a single
functional area.
(b) The exhaust air requirements shall be coordinated with the
equipment specifications. Maintain these spaces under negative
pressure.
(c) The supply air quantity for the locker rooms shall be the larger of
the two values calculated either to meet the cooling load requirements,
or the exhaust air requirements, associated with their integral
bathrooms and toilets.
(d) For the space to be maintained under negative pressure exhaust 15
percent more air than the supply. For the space to be maintained under
positive pressure, exhaust 15 percent less air than the supply air.
(e) In the absence of any specified supply air change/hour (See
Paragraph 1.3.4), the exhaust air shall be calculated from the
following considerations, and the maximum value, thus, derived, shall
be used:
(1)
Space Heat Gain
(2)
Equipment Exhaust Requirements
(3)
Applicable Codes
(4)
15 percent of the supply air
(f) Individual toilets and HACs do not require ducted supply air. Use
air transferred from the occupied spaces via door grilles and/or
undercuts, to exhaust these areas. Do not transfer more than 4.2 Cu
M/Min (150 CFM) of air per door undercut.
(g) Public toilets and congregate baths do require ducted supply air up
to 8.5 air changes per hour maximum. The balance air should be drawn
from the corridors to maintain negative pressure and to ensure exhaust
of 10 air changes per hour.
1.3.7 AIR PRESSURE RELATIONSHIP
Provide balance between the supply and exhaust air quantities as noted
in Table 1-4.
1.3.7.1 The designer shall ensure that the make-up air required to
maintain negative pressure, and the excess air to maintain positive
pressure, are available and taken into account in the air balance
calculations.
HVAC DESIGN MANUAL
1-14
GENERAL REQUIREMENTS
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