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BEAM P
LUS FOR
N
EW
B
UILDINGS
I
NDOOR
E
NVIRONMENTAL
Q
UALITY
(I
EQ
)
V
ERSION
1.2
I
EQ
18 R
OOM
A
COUSTICS
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 179
6
IEQ
6.7
A
COUSTICS AND
N
OISE
I
EQ
18 R
OOM
A
COUSTICS
E
XCLUSIONS
Buildings/premises where speech intelligibility is not important, and
rooms of a special acoustical nature.
O
BJECTIVE
Improve the acoustical properties of rooms in which speech intelligibility
is important.
C
REDITS ATTAINABLE
1
P
REREQUISITES
None.
C
REDIT REQUIREMENT
1 credit for demonstrating that internal noise levels are within the
prescribed criteria and the mid-frequency reverberation time in applicable
rooms meets the prescribed criteria for give types of premises.
Based on the nature of the building, relaxation should be allowed in
considering the acceptance of this credit. The applicant should provide
full submission of the design and calculation to justify the relaxation.
A
SSESSMENT
There is no single all-encompassing set of criteria that will define good
acoustical properties for all types of rooms and uses. The Client shall
define the criteria appropriate to the type and use of the premises/rooms
in the building. The criteria for intruding noise level will be expressed in
terms of NC level. However, for the purposes of assessment account
should be taken of the criteria given below. Where alternative criteria are
used the Client shall provide evidence as to the suitability of the
alternative, e.g. by making reference to authoritative guidance. Likewise,
where criteria appropriate to the type and use of premises/spaces are
not stated herein, the Client shall provide evidence as to the suitability of
the criteria adopted. Mid-frequencies refer to 500Hz, 1kHz and 2kHz.
The internal noise sources include air conditioning units, breakout noise
from air ducts, air grills, etc.
Compliance shall be demonstrated by detailed calculations, or
measurement, or both, depending on the Client’s preference. The
reverberation time shall be assessed using Sabine’s formula [ 1 ] or
similar alternative taking into account the room details and appropriate
assumptions about the materials in the space. Measurements during
commissioning shall use the method given in ISO 3382 [2] or equal
equivalent.
The Client shall submit details in the form of a report prepared by a
suitably qualified person providing a schedule of the premises and
spaces in the building, relevant design details as their impact on
acoustical properties, the rooms/premises subject to field tests or for
which detailed calculations have been made, the acoustical criteria used,
underlying assumptions, and the results of tests or calculations
demonstrating compliance with the criteria.
Where it can be demonstrated that the acoustical quality in a sample of
each type of room in which speech intelligibility is important, as
measured or calculated, meets appropriate performance criteria the
credit shall be awarded.
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
1
I.Sharland. Woods practical guide to noise control. Colchester, England.
2
International Standard Organization. ISO 3382. Acoustics - Measurement of the reverberation time of rooms with reference
to other acoustical parameters.