BS 7135-1:1989
Superseded
A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
View Superseded by
Noise emitted by computer and business equipment Method of measurement of airborne noise
Hardcopy , PDF
English
31-08-1989
25-10-2001
National foreword
Committees responsible
Method
0 Introduction
1 Scope and field of application
2 Conformance
3 References
4 Definitions
5 Method for determining sound power levels of
equipment in reverberation rooms
6 Method for determining sound power levels of
equipment over a reflecting plane
7 Method for measuring sound pressure levels at the
operator and bystander positions
Annexes
A Standard test table
B Alternative measurement surfaces for sound power
measurements in accordance with clause 6
C Installation and operating conditions for specific
equipment categories
D Measurement of impulsive sound pressure levels and
discrete tones at the operator position
Tables
1 Uncertainty in determining sound power levels in a
reverberation room
2 Minimum room volume as a function of the lowest
frequency band of interest
3 Procedures to be followed for measuring discrete-
frequency components or narrow bands of noise
4 Number of microphone positions required and
constant k for determining the number of equipment
locations
5 Values of the A-weighting Aj, for j = 1 to jmax = 7
6 Values of the A-weighting Aj, for j = 1 to jmax = 21
7 Uncertainty in determining sound power levels in a
free field over a reflecting plane
8 Coordinates of key microphone positions for
arrangement 1
9 Coordinates of key microphone positions for
arrangement 2
10 Uncertainty in determining time-average sound
pressure level at the operator position over a
reflecting plane
11 Hemispherical measurement surface - 10 measurement
positions
12 Hemispherical measurement surface - 10 measurement
positions
13 Number of characters to be used
Figures
1 Measurement surface with 9 microphone positions
2 Measurement surface for floor-standing equipment in
front of a wall
3 Examples of microphone positions for standing and
seated operators
4 Example of a standard test table
5 Hemispherical surface - 10 measurement positions
6 Hemispherical measurement surface - Circular paths
for microphone traverse
7 Insertion of a single sheet of paper
8 Example of full print page: line length of 60 to 110
characters
9 Example of full print page: line length of more than
110 characters
Methods for determining the A-weighted sound power levels based on measurements in reverberant rooms or in free-field conditions over a reflecting plane, and A-weighted sound pressure levels at the operator or bystander positions.
| Committee |
EH/1
|
| DocumentType |
Standard
|
| Pages |
46
|
| PublisherName |
British Standards Institution
|
| Status |
Superseded
|
| SupersededBy |
| Standards | Relationship |
| ISO 7779:2010 | Identical |
| EN 27779 : 1991 | Identical |
| ISO 7779:1988 | Identical |
| BS 7135-3:1989 | Noise emitted by computer and business equipment Method for determining and verifying declared noise emission values |
| BS 7135-2:1989 | Noise emitted by computer and business equipment Method of measurement of high-frequency noise |
| BS 4196-4:1981 | Sound power levels of noise sources Engineering methods for determination of sound power levels for sources in free-field conditions over a reflecting plane |
| BS 4196-0:1981 | Sound power levels of noise sources Guide for the use of basic standards and for the preparation of noise test codes |
| BS 4196-2:1981 | Sound power levels of noise sources Precision methods for determination of sound power levels for discrete-frequency and narrow-band sources in reverberation rooms |
| BS 7135-2:1989 | Noise emitted by computer and business equipment Method of measurement of high-frequency noise |
| BS 7135-3:1989 | Noise emitted by computer and business equipment Method for determining and verifying declared noise emission values |
| BS 4196-5:1981 | Sound power levels of noise sources Precision methods for determination of sound power levels for sources in anechoic and semi-anechoic rooms |
| ISO 6926:2016 | Acoustics — Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels |
| BS 4196-1:1981 | Sound power levels of noise sources Precision methods for determination of sound power levels for broad-band sources in reverberation rooms |
| BS 4196-3:1981 | Sound power levels of noise sources Engineering methods for determination of sound power levels for sources in special reverberation test rooms |
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