June 99
1.
Actual take-offs from the system layout drawings,
that is, without any approximation for fittings,
system components, etc.
2.
Equal friction or static regain method.
E.
FAN AND MOTOR SELECTION: Increase the KW
(HP), calculated on the basis of total air quantity and
fan static pressure, by 10% to account for drive losses
and field conditions. The motor selection shall make
an allowance for:
1.
Altitude
2.
Temperature
3.
Inlet/Outlet Conditions
4.
System Effect Factors Per AMCA 210
The fan(s) shall be selected to operate in the stable
region at near the maximum static efficiency.
2.6
DUCT SIZING CRITERIA: As far as possible, design all
supply, return, and exhaust air ductwork as low velocity/low
pressure type with a limiting maximum velocity of 7.6 m/s
(1500 fpm) and a static pressure drop of 25 Pa (0.1 inch
water gage) per 30 m (100 equivalent feet) of duct length.
2.7
NOISE CRITERIA: In all occupied areas to be
mechanically cooled, maintain NC 40 in all octave bands.
The systems must be engineered and the use of acoustic
sound lining and sound attenuaters shall be considered to
achieve the design sound levels. For vehicular
maintenance areas NC 50 shall be the maximum design
noise level in all octave bands.
2.8
SEISMIC BRACING CRITERIA: Refer to article 4,
Applicable Construction Criteria, and VA Standard Details.
2.9
VIBRATION CRITERIA: Refer to the VA Master
Specifications section 15200, NOISE AND VIBRATION
CONTROL, and Supplement ATTACHMENT NO. 1.
3.
HVAC SYSTEMS:
3.1
CEMETERY BUILDINGS:
VA Design Guide -- National Cemetery Administration
Page 5 -58
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