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BEAM P
LUS FOR
E
XISTING
B
UILDINGS
I
NDOOR
E
NVIRONMENTAL
Q
UALITY
(I
EQ
)
V
ERSION
1.2
I
EQ
19 R
OOM
A
COUSTICS
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 142
P
ERFORMANCE
C
RITERIA
a) Office type premises
The reverberation time of A-weighted sound pressure level, in modular
(private) offices and conference rooms, shall be 0.6 s or below. The
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 NC35.
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 NC30.
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.
d) Indoor games halls & indoor swimming pools etc
The reverberation time of A-weighted sound pressure level, in door game
halls, indoor swimming pools or other recreations premises, shall be 2.0s
or below. The noise assessment criterion shall be NC45.
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 how quickly sound decays
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, there is reasonable agreement than other types of
measurements are needed for a more 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.