SIST EN ISO 26101-1:2022 PDF

Acoustics - Test methods for the qualification of the acoustic environment - Part 1: Qualification of free-field environments (ISO 26101-1:2021)

Title (English):

SIST EN ISO 26101-1:2022

Acoustics - Test methods for the qualification of the acoustic environment - Part 1: Qualification of free-field environments (ISO 26101-1:2021)

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 30
Publication date:: June 16, 2022
ICS:: 17.140.01
Technical committee:: AKU - Acoustics

Document language:

enru

Delivery time:1–7 days

Price:82 €

Description (English):

This document specifies methodology for qualifying acoustic spaces as anechoic and hemi-anechoic spaces meeting the requirements of a free sound field. This document specifies discrete-frequency and broad-band test methods for quantifying the performance of anechoic and hemi-anechoic spaces, defines the qualification procedure for an omni-directional sound source suitable for free-field qualification, gives details of how to present the results and describes uncertainties of measurement. This document has been developed for qualifying anechoic and hemi-anechoic spaces for a variety of acoustical measurement purposes. It is expected that, over time, various standards and test codes will refer to this document in order to qualify an anechoic or hemi-anechoic space for a particular measurement. Annex D provides guidelines for the specification of test parameters and qualification criteria for referencing documents. In the absence of specific requirements or criteria, Annex A provides qualification criteria and measurement requirements to qualify anechoic and hemi-anechoic spaces for general purpose acoustical measurements. This document describes the divergence loss method for measuring the free sound field performance of an acoustic environment.

Technical details

SKU: SIST EN ISO 26101-1:2022

Abstract

Overview

EN ISO 26101-1:2022 (ISO 26101-1:2021) specifies standardized test methods to qualify acoustic test spaces as free-field environments - principally anechoic and hemi-anechoic chambers. Developed by ISO/TC 43 and adopted by CEN, the standard defines how to quantify free sound field performance using both discrete-frequency and broadband measurements, how to qualify an omni‑directional sound source, and how to present results including measurement uncertainty.

Key topics and requirements

Divergence loss method: Primary measurement technique described for assessing how closely a space approximates a free sound field (reduction of sound pressure with distance).
Allowable deviations from the inverse square law: Measured sound pressure deviations from theoretical spherical spreading are evaluated against criteria specified by referencing documents or, if none exist, the criteria in Annex A.
Test signals and instrumentation: Procedures cover discrete and broadband methods, microphone traverses, and placement of test sources; references normative standards for equipment (e.g., IEC sound level meters and filter specifications).
Omni‑directional sound source qualification: A procedure (including Annex B) for evaluating source directionality so the source is suitable for free-field qualification.
Uncertainty and reporting: Guidance on expressing measurement uncertainty (aligned with ISO/IEC Guide 98-3/GUM) and required information to record and report (Annex C and main text).
Annexes for implementation:
- Annex A: Default qualification criteria and measurement requirements for general-purpose acoustical measurements.
- Annex B: Procedure for evaluating source directionality.
- Annex C: Measurement uncertainty guidance.
- Annex D: Guidelines for referencing this method in other standards/test codes.

Practical applications and users

This standard is essential for:

Acoustic test laboratories qualifying anechoic and hemi-anechoic chambers for product noise testing (microphones, loudspeakers, automotive components, electronics).
Chamber designers and manufacturers verifying free-field performance during commissioning.
Acoustic engineers and consultants who need repeatable, comparable qualification data for measurements made in free-field environments.
Standards writers and certification bodies that will reference EN ISO 26101-1 to specify qualification criteria for specific test protocols.

Benefits include consistent qualification across facilities, clearer reporting of chamber performance, and reduced uncertainty in subsequent acoustic measurements.

Related standards

ISO/IEC Guide 98-3 (GUM) - uncertainty of measurement
IEC 61672-1 - sound level meter specifications
IEC 61260-1 - octave and fractional-octave filters
Future part: ISO 26101-2 (environmental correction) - linked in the ISO 26101 series

Keywords: acoustics, free-field, anechoic chamber, hemi-anechoic, divergence loss, ISO 26101-1, EN ISO 26101-1:2022, chamber qualification, measurement uncertainty, omni-directional sound source.

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and requirements

Divergence loss method: Primary measurement technique described for assessing how closely a space approximates a free sound field (reduction of sound pressure with distance).
Allowable deviations from the inverse square law: Measured sound pressure deviations from theoretical spherical spreading are evaluated against criteria specified by referencing documents or, if none exist, the criteria in Annex A.
Test signals and instrumentation: Procedures cover discrete and broadband methods, microphone traverses, and placement of test sources; references normative standards for equipment (e.g., IEC sound level meters and filter specifications).
Omni‑directional sound source qualification: A procedure (including Annex B) for evaluating source directionality so the source is suitable for free-field qualification.
Uncertainty and reporting: Guidance on expressing measurement uncertainty (aligned with ISO/IEC Guide 98-3/GUM) and required information to record and report (Annex C and main text).
Annexes for implementation:
- Annex A: Default qualification criteria and measurement requirements for general-purpose acoustical measurements.
- Annex B: Procedure for evaluating source directionality.
- Annex C: Measurement uncertainty guidance.
- Annex D: Guidelines for referencing this method in other standards/test codes.

Practical applications and users

This standard is essential for:

Acoustic test laboratories qualifying anechoic and hemi-anechoic chambers for product noise testing (microphones, loudspeakers, automotive components, electronics).
Chamber designers and manufacturers verifying free-field performance during commissioning.
Acoustic engineers and consultants who need repeatable, comparable qualification data for measurements made in free-field environments.
Standards writers and certification bodies that will reference EN ISO 26101-1 to specify qualification criteria for specific test protocols.

Benefits include consistent qualification across facilities, clearer reporting of chamber performance, and reduced uncertainty in subsequent acoustic measurements.

Related standards

ISO/IEC Guide 98-3 (GUM) - uncertainty of measurement
IEC 61672-1 - sound level meter specifications
IEC 61260-1 - octave and fractional-octave filters
Future part: ISO 26101-2 (environmental correction) - linked in the ISO 26101 series

Keywords: acoustics, free-field, anechoic chamber, hemi-anechoic, divergence loss, ISO 26101-1, EN ISO 26101-1:2022, chamber qualification, measurement uncertainty, omni-directional sound source.

SIST EN ISO 26101-1:2022 PDF

Technical details

Abstract

Overview

Key topics and requirements

Practical applications and users

Related standards

Related standards

Abstract

Overview

Key topics and requirements

Practical applications and users

Related standards

Related standards

Acoustics — Test methods for the qualification of the acoustic environment — Part 1: Qualification of free-fi…

Electroacoustics - Sound level meters - Part 1: Specifications

Electroacoustics - Octave-band and fractional-octave-band filters - Part 1: Specifications

Acoustics - Test methods for the qualification of the acoustic environment - Part 2: Determination of the env…