06-06
an analysis showing the expected noise levels for the
prior approval of VA.
3.
The systems must be engineered and the use of acoustic
sound lining and sound attenuators should be considered to
achieve the design sound levels.
B. COOLING TOWERS: Select and locate the cooling towers to avoid
problems with:
1. Noise
2. Vibrations
3. Esthetics
4. Drift
6. Air Recirculation
2.7 VIBRATION CRITERIA
Refer to the VA Master Specifications Section 15200, NOISE AND VIBRATION
CONTROL and Supplement No.5.
2.8 SEISMIC BRACING CRITERIA
Refer to Article 8.
2.9 EQUIPMENT SIZING CRITERIA
A. LOAD CALCULATIONS: The cooling/heating loads shall be calculated in
accordance with the method outlined in ASHRAE Handbook of
Fundamentals.
B. SAFETY MARGIN: A safety margin of 10% shall be added to the
calculated internal heat gain and loss to allow for any future
increase in internal heat gain or other load demand.
The calculated
air quantities for the occupied spaces shall be based on the addition
of the safety margin.
Even when the supply air quantities are
established on the basis of fixed air changes per hour or to meet the
exhaust requirements through the fume hoods, the supply air terminal
units shall be selected to handle possible 10% more air volume.
The
set points of the supply air terminal units shall, however, reflect
the actual operating conditions.
C. AIR LEAKAGE: An allowance of 4% shall be made for the leakage of air
through the ductwork before it reaches the occupied spaces.
The
leakage allowance shall be applied to the sum of all individual peak
air quantities without any diversity.
Do not compute the supply air
fan volume on the basis of block or zone loads wherein the load (and
air volume) diversities are inherently built in the calculations.
Example: Variable Air Volume Systems for support areas.
D. STATIC PRESSURE: A safety margin of 10% shall be added to the fan
total static pressure of the system.
The static pressure
calculations shall be based on:
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