BS 5944-2:1992

Committees responsible
National foreword
Introduction
Method
1 Scope
2 Normative references
3 Definitions
4 Measurement uncertainty
5 Test environment
6 Instrumentation
7 Installation conditions
8 Operation conditions
9 Location and number of sound measurement points
10 Test procedure
11 Information to be recorded
12 Test report
13 Identification statement (Reference to this part of
     ISO 4412)
Annexes
A Calculation of sound levels
B Errors and classes of measurement
C Guidelines for the application of this part of ISO
     4412
D Bibliography
Tables
1 Standard deviation of sound power level
     determinations
2 Allowable variations of mean indicated values of
     controlled parameters
B.1 Permissible systematic errors of measuring
     instruments as determined during calibration
Figures
C.1 Transmission paths of sound energy from pumps
C.2 Instrumentation for manual data logging
C.3 Multiple microphone scanning instrumentation
C.4 Corrections for background noise
C.5 Pump noise test configuration with hemispherical
     measuring array
C.6 Mounting and driveline arrangement for
     hemispherical measuring array
C.7 "Minimized" motor mount (two-bolt flange mounting
     configuration)
C.8 Diagrammatic views of the hemispherical layout
     showing fluid line cladding
C.9 Example of test circuit

Establishes a test code describing procedures for the determination of the sound power levels of a hydraulic fluid power motor (under controlled conditions of operation and installation) suitable for giving a basis for comparing the noise levels of motors in: octave band sound power levels and a weighted sound power level. Applies to all types of hydraulic fluid power motors operating under steady-state conditions, irrespective of size, except for any limitations that the size of the test environment may impose.

This part of ISO 4412 establishes a test code describing procedures, based on ISO 2204, for the determination of the sound power levels of a hydraulic fluid power motor, under controlled conditions of installation and operation, suitable for providing a basis for comparing the noise levels of motors in terms of:

• A-weighted sound power level;
• octave band sound power levels.

From these sound power levels, if required, reference sound pressure levels may be calculated for reporting purposes in accordance with Annex A.

For general purposes, the frequency range of interest includes the octave bands with centre frequencies between 125 Hz and 8 000 Hz.¹⁾

Due to the inherent difficulties in the measurement of low-speed motor performance, this part of ISO 4412 is limited to motors operating at speeds exceeding 50 r/min.

Guidelines for the application of this part of ISO 4412 are given in Annex C.

This part of ISO 4412 is applicable to all types of hydraulic fluid power motors operating under steady-state conditions, irrespective of size, except for any limitations imposed by the size of the test environment (see clause 5).