4.3 NOISE, VIBRATION CONTROLS & MEASURES

4.3.1 SCOPE

The air conditioning contractor shall take all necessary precautions to have minimum noise generation and its transmission. Minimum vibration as permitted by ISO standard shall be followed. A few points for guidance only are given below:

a) Double fire retardant flexible connections shall be provided from air discharge to outlet of air-handler to the duct.

b) Vibration isolation pads of suitable thickness (min 25mm) commensurate to loading for isolation of vibration shall be provided under all pumps, air handlers fans etc. in consultation with manufacturer for proper selection of vibration isolators

c) Vibration isolation springs of suitable size to suit the weight of water chilling machine as recommended by the manufacturer for elimination of vibrations.

d) Flexible conduit connections of minimum diameter of 50mm to motors shall be provided. All loops should be large enough to allow connections to remain flexible.

e) All conduit connection where conduits are 60mm or larger shall be made of 1.2 meters minimum length conduit installed in the shape of U and grossly slack to provide maximum vibration isolation.

f) All end suction pumps shall be bolted and grouted to the inertia base which in turn shall be supported on suitable vibration isolation rubber pads duly sandwitched with 24G GI sheets. Concrete inertia blocks shall be formed of suitable thickness and of adequate mass.

g) The floor supported piping shall be mounted on pipe supports with min. 7.5mm ribbed neoprene pads between the base plate of the pipes and the floors.

h) All items suspended from false ceiling shall be isolated on separate hangers.

i) In case of ducts, conduits, pipes & tubes the annular space between construction and penetrating element shall be sealed with sand cement plaster/suitable other material.

j) The supply duct starting from air handling unit & plenum shall be provided with 15 mm thick acoustic lining (140 kg/m3) as indicated in the

P-4.3, 1 out of 2

schedule of quantities. All Fan Coil Units (wherever used) collar shall also be lined with 12 mm thick acoustically lined. The duct lining shall be done with closed cell nitrile rubber based material having min. density of 140 kg/cubic meter.

k) All piping connection to pumps and chilling machine shall be through flexible rubber bellows.

l) The air-conditioning contractor shall take all other precautions or shall make his own arrangements even if not specified in the tender documents for eliminating high noise levels & shall minimize vibrations in all mechanical equipments without any additional cost.

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