August_1970 — Page 35

b). The floating floor serves two functions. It isolates the vibration of the equipment from the structure (reducing impact noise considerably) and is a major component in reducing airborne noise.

c). The isolated ceilings with their airspaces (independant of structure), coupled with the floor slabs, achieve as much reduction of airborne noise as do the normally much heavier construc- tions of the walls.

A construction such as this is ex- pensive. If the equipment room(s) can be 'on grade' and surrounded by 'dead' space, the majority of this sophistica- tion can be discarded.

Suggested general specification notes

Office

Job. No.

SECTION..

INTRODUCTION

Acoustics:

Acoustical treatment

In order to meet the prime func- tions of these areas, the design and materials must fulfil an important role in sound control. Sound absorbent and reflective materials are employed to attenuate and diffuse sound within rooms, to control reverberation time and prevent noticeable flutter and echo.

in constructing floors, walls and roofs ings and described in the specifica- to reduce the transmission of noise

tions. from outside or between rooms and

areas.

1. GENERAL

All work and material described in this section shall apply to construction of ......

and shall be in accordance with these specifications and the pro- duction drawings. Careful attention is to be given to the following rooms and

areas:

Room &

areas

Reference drawings

Remarks

theatre $10

Projection

Directors'

suites T6-15

Conference

room T54 etc., etc.

2. GENERAL CONDITIONS

All work in this section shall be governed by the 'Articles of Agree- ment......

3. SCOPE OF WORK

(A) Extent:

The work required under this sec- tion consists of all acoustical treat- ment and related items necessary to Sound insulating materials are used complete the work indicated on draw-

i. Acoustical treatment.

ii. Tuning procedures (if required). iii. Special conditions to be considered during construction.

(B) List of items included: i. Labour, materials, tools, equipment, appliances and services necessary to furnish, deliver and install acoustical treatment and related work, complete in accordance with the applicable drawings and/or as herein specified. ii. Anchors, hangers, carrying mem- bers, and mechanical suspension sys- tems for support of all components for suspended acoustical ceilings, recessed, surface mounted and suspended light. ing fixtures, ventilation and air-con- ditioning supply and return grilles and diffusers (and electrical trunking and cable trays if rquired).

iii. Anchors, isolating hangers, carry- ing members and mechanical suspen- sion system for support of all com- ponents for suspended plaster ceilings, lighting fixtures and A/C grilles and diffusers in ......

iv. Suspended acoustical ceilings in all locations where indicated on drawings, finish schedule and/or as herein speci- fied.

v. Adhesive applied acoustical ceiling tile to underside of plaster ceilings in all locations where indicated on drawings and finish schedules.

vi. Wall edging and/or closure mould-

(Packed sleeve

Absorbent treatment

DUCT

MUFFLER

PACKAGE

AC UNIT

Floor & equipments

PLENUM

BLOWER

isolators

FLIGHT

AIR DUCT

| Plaster ceiling

Isolation Hangers

Fig. 2. Floating floor and isolation system

Far East BUILDER, August 1970

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