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BEAM P
LUS FOR
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UILDINGS
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NVIRONMENTAL
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1.2
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EQ
18 R
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COUSTICS
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 180
noise assessment criterion shall be NC40.
b) Classrooms and similar premises
The reverberation time of A-weighted sound pressure level in teaching
rooms, other than specialist teaching rooms such as laboratories and
workshops, shall be 0.6 s or below. The noise assessment criterion shall
be NC 35.
c) Residential premises, hotel and apartments
The reverberation time of A-weighted sound pressure level, in bedrooms
and living rooms, shall be between 0.4 and 0.6 s. The noise assessment
criterion shall be NC 30.
d) Indoor games halls & indoor swimming pools etc
The reverberation time of A-weighted sound pressure level, in indoor
game halls, indoor swimming pools or other recreational premises, shall
be 2.0 s or below. The noise assessment criterion shall be NC 45.
Criteria from standards and guides from authoritative sources should be
referenced. For example, Table 8 of BS 8233 [3] provides a guide to
reverberation time in unoccupied rooms for speech and music.
B
ACKGROUND
A first step in architectural acoustic design is to identify appropriate
values of reverberation time for the intended use of a room and then to
specify materials to be used in the construction which will achieve the
desired value of the reverberation time for a given space and use.
The focus for BEAM is on the acoustical qualities in workplaces such as
offices and classrooms, libraries, and places of residence, etc. Whilst the
matter of room acoustics is complex, and defining performance by a
single indicator is problematic, an important acoustical measurement is
the reverberation time. It is used to determine the decay rate of sound in
a room, and offers a relatively simple assessment of acoustical design.
BEAM is not intended to replace design standards. It sets criteria for
good acoustical quality while the design guidelines and standards
established in other countries can also be considered.
Whilst reverberation time continues to be regarded as a significant
parameter, other types of measurements are needed for a complete
evaluation of acoustical quality of rooms. With respect to the standards
and guides recommendations, ANSI [ 4 ] suggests the maximum
reverberation time of A-weighted sound pressure level in classrooms and
similar learning spaces. However, for office type premises, residential
premises, hotels and apartments there seems to be little available in the
way of standards or guides. ASTM [5] gives an alternative parameter,
speech privacy in open offices, for an average speech spectrum using
the Articulation Index Method.
3
British Standards Institution BS8233:1999 – Sound insulation and noise reduction for buildings – Code of Practice.
4
American National Standard ANSI S12.60-2002.
5
ASTM International. Designation E1130-02. Standard Test Method for Objective Measurement of Speech Privacy in Open
Offices Using Articulation Index.