Committees responsible
National foreword
Introduction
Method
1 Scope
2 Normative references
3 Definitions
4 Acoustic environment
5 Instrumentation
6 Object under test and test conditions
7 Sound pressure levels on the measurement surface
8 Calculation of surface pressure level, sound power
level and directivity factor
9 Information to be recorded
10 Test report
Annexes
A (normative) Qualification procedures for the
acoustic environment
B (informative) Examples of suitable instrumentation
systems
C (informative) Calculation of directivity index and
directivity factor using a hemispherical microphone
array
D (informative) Bibliography
Tables
1 International Standards specifying various methods
for determining the sound power levels of machines
and equipment
2 Limits for correction
3 Uncertainty in determining sound power levels,
expressed as the largest value of the standard
deviation
4 Correction for background noise
Figures
1 Identification of the principal noise sources
2 Microphone locations (9 positions) and measurement
surface for small gas turbine sets
3 Microphone locations and measurement surface for
medium-sized gas turbine sets
4 Microphone locations for large gas turbine sets
5 Measurement surface and microphone positions for
measuring the intake-inlet noise when no reflecting
plane exists
6 Measuring surface and microphone positions for
measuring the intake-inlet noise emitted from inlet
systems of the gas turbine
7 Measurement surface and microphone positions for
measuring exhaust-outlet noise when no reflecting
plane exists
8 Measurement surface and microphone positions for
measuring exhaust-outlet noise when b/a < 1,5
9 Measurement surface and microphone positions for
measuring exhaust-outlet noise when b/a > 1,5
A.1 Environmental correction K, in decibels