ISO 26101-2-2024 PDF

Full title and description

Acoustics — Test methods for the qualification of the acoustic environment — Part 2: Determination of the environmental correction. This international standard specifies methods to qualify environments that approximate a free acoustic field near one or more reflecting planes, and to determine the environmental correction used when deriving sound power or sound energy levels from surface sound pressure measurements around a noise source.

Abstract

This document provides procedures to measure and report the environmental correction (CE) that accounts for reflected sound in test environments used to determine sound power or sound energy from surface sound pressure measurements. It clarifies how CE depends on test-environment reflections and on the shape and size of the measurement surface, and treats those differences within the stated measurement uncertainty.

General information

• Status: Published.
• Publication date: June 2024 (Edition 1).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.140.01 (Acoustic measurements and noise abatement — general).
• Edition / version: Edition 1 (2024).
• Number of pages: 15 (as listed in the ISO bibliographic entry).

Scope

The standard applies to environments that approximate an acoustic free field in the vicinity of one or more reflecting planes and specifies test methods to determine the environmental correction (CE) used to compensate for reflected sound when calculating sound power or sound energy from surface sound pressure measurements around machinery or equipment. It is intended to be referenced by measurement standards that require qualification of the test environment.

Key topics and requirements

• Definition and purpose of the environmental correction (CE) for surface-based sound power/energy determinations.
• Test procedures to qualify environments approximating a free field near reflecting planes.
• Consideration of measurement-surface shape and size and their influence on CE and measurement uncertainty.
• Reporting requirements and treatment of uncertainty for CE determinations.

Typical use and users

Used by acoustic laboratories, test houses, manufacturers of machinery and equipment, product certification bodies, and standards developers to qualify test environments and apply the appropriate environmental correction when determining sound power or sound energy levels from surface measurements. It supports consistent application of environment correction across reference measurement standards.

Related standards

Part of the ISO 26101 series. Key related documents include ISO 26101-1:2021 (Qualification of free-field environments) and various acoustic measurement standards that reference environment qualification procedures (for example standards dealing with sound power determination such as ISO 3746 and related methods).

Keywords

Acoustics; environmental correction; CE; free field; hemi-anechoic; sound power; sound energy; surface measurements; measurement uncertainty; test environment qualification.

FAQ

Q: What is this standard?

A: ISO 26101-2:2024 is an international standard that specifies test methods to determine the environmental correction used when calculating sound power or sound energy from surface sound pressure measurements in environments approximating a free field near reflecting planes.

Q: What does it cover?

A: It covers procedures to qualify the acoustic environment, procedures to determine the environmental correction (CE), how CE depends on reflected sound and measurement-surface geometry, and how to report CE together with its associated uncertainty.

Q: Who typically uses it?

A: Acoustic test laboratories, manufacturers performing sound power/energy measurements, conformity assessment bodies, and standards committees that reference qualified test environments.

Q: Is it current or superseded?

A: It is current (published June 2024, Edition 1). Users should check national adoptions or harmonized versions where applicable for implementation dates in their region.

Q: Is it part of a series?

A: Yes. It is Part 2 of the ISO 26101 series; ISO 26101-1:2021 (Part 1) addresses qualification of free-field environments and is commonly used together with Part 2.

Q: What are the key keywords?

A: Environmental correction (CE), free field, sound power, sound energy, surface measurements, measurement uncertainty, acoustic environment qualification.