206 / 248
BEAM P
LUS FOR
N
EW
B
UILDINGS
I
NDOOR
E
NVIRONMENTAL
Q
UALITY
(I
EQ
)
V
ERSION
1.2
I
EQ
20 B
ACKGROUND
N
OISE
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 185
measured or calculated for the most susceptible spaces/rooms/premises,
meets appropriate performance criteria the credit shall be awarded.
A
SSESSMENT
C
RITERIA
a) Offices
Modular (private) offices and small conference rooms: 40 dB L
Aeq,T
=8
hr or 45 dB L
Aeq
,T=5 mins.
Large landscaped offices: 45 dB L
Aeq,T
=8hr or 50 dB L
Aeq,T
=5min.
b) Classrooms
Background noise shall be below 45 dB L
Amax
in schools in urban areas,
otherwise at or below 40 dB L
Amax
, effective between the hours of 08:00
to 16:00.
c) Residential premises and hotel rooms
In bedrooms under window closed conditions at or below 30 dB
L
Aeq,T
=8 hr, or 35 dB L
Aeq,T
=5 mins, and < 45 dB between 23:00 to
07:00.
In habitable rooms (other than kitchens) under closed window
conditions < 55 dB L
Aeq
,
T
=16 hrs between 07:00 to 23:00.
d) Indoor games halls & indoor swimming pools etc
Background noise level shall be less than 50 dB L
Aeq,T
=5 mins.
Tables 5 and 6 of BS 8233 [2] give criterion for various activities in
buildings.
B
ACKGROUND
Background noise includes that from external sources as well as from
the building services equipment. Table 4.1 in Chapter 9 of the Hong
Kong Standards and Planning Guidelines provides a summary of
maximum permissible noise levels at the external facade applicable to
building uses which rely on operable windows for ventilation. Guidance
on separation distances between road traffic and rail traffic and
residential buildings is given in the Guidelines.
Calculations can be made in terms of L
Aeq,T
according to BS 8233, where
T = 16 h (daytime) and 8 h (night time), appropriate to the criteria
chosen. Calculations using the statistical energy analysis [3] are also
acceptable. In centrally air-conditioned premises while NC, NR, PNC,
NCB and RC are acceptable criteria for noise from air-conditioning
equipment, the presence of outside noise sources renders L
Aeq,T
a better
performance indicator for the aural environment [4]
Noise levels at the facade of a building can be established by
measurement or prediction by simulation methods approved by the
Environmental Protection Department. Predictions should take into
consideration future as well as existing land uses. Estimation of road
traffic noise can be made using the UK Department of Transport’s
prediction method [5]. For railway noise, calculations shall be made in
terms of L
Aeq,T
using the UK Department of Transport’s prediction method
[6]. For noise from industry which is more or less of steady level, L
Aeq,T
is
estimated according to British Standard BS 4142 [7]. T in the case can
be 1 hr or 30 minutes.
2
British Standard Institution. BS 8233 Code of Practice for sound insulation and noise reduction for buildings.
3
European Committee for Standardization. CEN EN 12354 Building Acoustics – Estimation of acoustic performance of
buildings from the performance of elements. Bruxelles.
4
Chan D W T, Tang S K, Burnett J. Noise Criteria for Hong Kong Building Environmental Assessment Method for New
Offices and Existing Offices (HK-BEAM). HKIE Transactions. HKIE Transactions, Vol. 5, No. 2, 1998, pp. 1-5.
5
UK Department of Transport. The Calculation of Road Traffic Noise. HM Stationary Office.
6
UK Department of Transport. The Calculation of Railway Noise. HM Stationary Office.
7
British Standards Institution. Method for rating industrial noise affecting mixed residential and industrial areas. British
Standard BS 4142:1990. London, BSI, 1990.