06-06
NOTES:
1. The above NC levels must be attained in all octave bands.
2. The above NC levels may be increased for the areas equipped
with fan coil units. The designer shall submit an analysis
showing the expected noise levels for the prior approval of
VA.
3. The systems must be engineered and the use of sound lining
(where allowed), sound attenuators, etc., should be
considered to achieve the design sound levels.
B. COOLING TOWERS: Elect and locate the cooling towers to avoid problems
with noise, vibrations, esthetics and air circulation. The designer
shall provide a noise analysis of the proposed cooling tower relative
to the adjacent occupancies. If the cooling tower fails to meet the
noise level of 60 dba at 50 feet distance, the following options
shall be evaluated:
1. Select different type of cooling tower.
2. Select different location(s) for cooling tower.
3. Consider acoustic treatment. For critical locations, the above
requirement of 60dBa may be lowered.
2.7 VIBRATION CRITERIA
Refer to the VA Master Specifications Section 15200, NOISE AND
VIBRATION CONTROL and Supplement, Attachment No. 5.
2.8 SEISMIC BRACING CRITERIA
Refer to Section 8.
2.9 HVAC EQUIPMENT SIZING CRITERIA
A. AIR HANDLING EQUIPMENT: Tom compensate for the duct air leakage
and any future space internal heat gain, the equipment shall be
sized in accordance with the following guidelines
1. Load Calculations: The design heat gain calculations shall be
done in accordance with the procedure outlined in the latest
ASHRAE Handbook of Fundamentals. The calculations, performed
either manually or with a computer program, shall not include
any built-in safety factors.
The calculated supply air volume shall be the sum of all
individual peak room air quantities without any diversity;
including for the variable air volume systems.
2. Safety Margin: A safety factor of 10% shall be applied to the
calculated room air quantity to allow for any future increase
in the room internal load.
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