ARCHITECTURAL ACOUSTICS
19708
by Ian Campbell; DA (Edin.), ARIBA, MASA
III. Specification & supervision
IN analysing the requirements of an acoustical specification for those areas or enclosures requiring above average acoustical consideration, the following items must be taken into account.
a). Extra noise protection means more sophisticated and usually more composite construction. This inevit-
PANEL
GLASS)
SPANDREL BEAN
CEILING DIFFUSER
HEAT UNIT
כי
MOBILE PARTITIO
PARTITIONS
PARTITION JOINT
.DUCT
ably raises costs and therefore protec- tion should be limited to the areas where its use is justified.
b). Containing noise at its source wherever possible is the easiest means of reducing noise control require-
ments.
c). List and categorise the specific
SUSPENDED CEILING
-FLOOR
SYSTEM
Fig. 1. Transmission of noise between adjacent flanking paths. (Arch. Rec., June 1959).
constructions and areas involved, both in drawings and specifications.
d). Keep the language and descrip- tion in the specification as simple and direct as possible, and cross refer- enced. Over dramatic and complex descriptions frighten the reader, es- pecially if he is lacking experience in this field.
e). Only in exceptional circum- stances should there be a need to em- ploy exotic and little known materials.
f). A simple list of acceptable manufacturers and/or suppliers of materials is a great help to both the builder and the job superviser, par- ticularly for materials such as fibre- glass, rockwool (asbestos fibre), etc., where specific properties are called for.
g). In highly specialised buildings (studios, auditoria, etc.) where bills of quantities are employed, a separate section should be considered for acoustical materials employed in achieving close tolerance design in room acoustics and where an acou- stical consultant is to be employed, bring him into the project at the be- ginning.
The prime reason for an acoustical specification is to draw attention to the areas requiring extra care in con- struction beyond the 'average building method'. If strict adherence to the best construction practices were fol- lowed the 'care' factor would be greatly reduced. Unfortunately 'best practice' is very rarely attained.
In noise control, the diagram in Fig. 1 indicates some of the problems facing the designer initially.
The diagram in Fig. 2 shows a typical floating floor and isolation system for an equipment room when located within the interior of a build- ing.
Note
a). The wall and ceiling absorbent treatment deadens the noise and takes the sharpness from it, but only frac- tionally reduces the intensity.
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Far East BUILDER, August 1970