ISO 3746-2010 PDF

Full title and description

Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound pressure — Survey method using an enveloping measurement surface over a reflecting plane. ISO 3746:2010 specifies a survey-grade procedure to estimate the sound power (or sound energy for transient/burst noise) of machinery, equipment or other noise sources from sound pressure measurements taken on a measurement surface that envelops the source and terminates on one or more reflecting planes (for example a floor or test-room surfaces).

Abstract

ISO 3746:2010 provides practical methods, test-environment criteria and correction procedures to derive A-weighted sound power levels and sound energy levels from measured sound pressure on an enveloping surface. The standard is intended to give results consistent with accuracy grade 3 (survey grade) as defined in ISO 12001 and includes guidance on measurement surfaces (hemispherical, half‑hemispherical, parallelepiped), microphone positions, background-noise correction, environmental correction, instrumentation and uncertainty estimation.

General information

• Status: Published / Current (ISO 3746:2010).
• Publication date: 25 November 2010 (third edition, 2010).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.140.01 — Acoustic measurements and noise abatement in general.
• Edition / version: 3rd edition — ISO 3746:2010.
• Number of pages: 48 (typical ISO edition length; national adoptions may show small variations).

Scope

Specifies a survey (control) method for determining sound power levels and sound energy levels of noise sources from sound pressure measurements on an enveloping measurement surface that terminates on a reflecting plane. Applicable to steady, fluctuating and transient (burst) noise types and to a wide range of sources (machines, installations, components) provided the test-environment and measurement criteria can be met. Provides requirements for test environment acoustic adequacy, instrumentation, microphone placement, measurement procedures, corrections and uncertainty estimation consistent with ISO 12001 (accuracy grade 3).

Key topics and requirements

• Measurement principle: derive sound power (or sound energy) from mean-square/A-weighted sound pressure measured over a defined enveloping surface terminating on a reflecting plane.
• Measurement surfaces and geometries: hemisphere, half-hemisphere, quarter-hemisphere and right parallelepiped configurations with specified radii/distances and microphone arrays (normative and informative annexes).
• Frequency bands and weighting: octave-band measurements typically from 125 Hz to 8 000 Hz and A-weighted overall levels for reporting.
• Corrections: background-noise correction (K1) and environmental/test‑environment correction (K2) to account for background and acoustic properties of the measurement site.
• Instrumentation and calibration: requirements and references for sound level meters and calibrators (cross-references to relevant IEC standards) and guidance on measurement procedure and repeatability.
• Uncertainty and accuracy: procedures to estimate measurement uncertainty; results conform to ISO 12001:1996 survey (accuracy grade 3) guidance.
• Applicability limits and test-environment criteria: guidance for indoor/outdoor use, reflecting-plane considerations, meteorological influences and altitude corrections where relevant.
• Informative annexes: microphone-array layouts, example calculations, guidance on environmental corrections and uncertainty evaluation.

Typical use and users

Used by acoustical engineers, test laboratories, product compliance teams, environmental assessors and occupational health professionals to obtain survey-grade estimates of machine and equipment noise emission. Typical applications include product noise declaration, pre-compliance testing, comparative machine noise surveys, environmental noise studies and workplace noise assessments when a full reverberation-room or precision method is not practical.

Related standards

Standards commonly used alongside or related to ISO 3746: ISO 3744 (engineering method — essentially free field over reflecting plane), ISO 3741 (precision methods for reverberation rooms), ISO 3743 series (engineering methods for small movable sources), ISO 3747 (in-situ/reverberant environments), ISO 12001 (accuracy grades and uncertainty guidance), ISO 11202 (emission sound pressure levels at work stations), and ISO 9614 (sound intensity methods). National and regional adoptions (EN ISO 3746, DIN EN ISO 3746, etc.) implement ISO 3746:2010 text with local status.

Keywords

acoustics, sound power level, sound energy level, survey method, enveloping measurement surface, reflecting plane, background-noise correction, environmental correction, accuracy grade 3, microphone array, machinery noise, noise emission testing.

FAQ

Q: What is this standard?

A: ISO 3746:2010 is an international standard that defines a survey (control) method for determining A-weighted sound power levels and sound energy levels of noise sources from sound pressure measurements on an enveloping measurement surface over a reflecting plane.

Q: What does it cover?

A: It covers test-environment criteria, measurement-surface geometries, microphone placement, required corrections (background and environmental), instrumentation and calibration guidance, example calculations and procedures to estimate measurement uncertainty consistent with survey-grade (accuracy grade 3) results.

Q: Who typically uses it?

A: Acoustical consultants, testing laboratories, manufacturers performing product noise assessment, environmental noise assessors and occupational hygiene professionals who need practical, repeatable survey-level sound power or sound energy estimates.

Q: Is it current or superseded?

A: ISO 3746:2010 is the third edition published in 2010 and is the current ISO text for the enveloping-surface survey method (it superseded earlier editions such as the 1995 version). Users should check national adoption status and any subsequent revisions or amendments before relying on it for regulatory compliance.

Q: Is it part of a series?

A: Yes — ISO 3746 is part of the ISO 374x family of acoustics standards covering methods for determining sound power/energy (including ISO 3741, ISO 3743, ISO 3744 and ISO 3747) and relates to ISO 12001 for uncertainty/accuracy grade definitions.

Q: What are the key keywords?

A: Sound power, sound energy, survey method, enveloping measurement surface, reflecting plane, background correction, environmental correction, accuracy grade 3, acoustic measurements.