ISO 4869-6:2019 音響—聴覚保護具—パート6：アクティブノイズリダクションイヤーマフの音響減衰の決定 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.

A list of all the parts in the ISO 4869 series can be found on the ISO website.

Introduction

Active noise reduction earmuffs are designed to provide additional attenuation of external sounds by means of a noise cancellation circuit. This additional attenuation is generally more effective at low frequencies. Such earmuffs can be selected for use in low-frequency dominated high noise environments.

1 Scope

This document is concerned with active noise reduction (ANR) earmuffs. It specifies the test methods for the determination of the active insertion loss and calculation procedures for deriving the total attenuation. For this aim, the values of sound attenuation in the passive mode also have to be known and are determined according to ISO 4869-1. These methods are intended for steady noise exposures and are not applicable to noises containing impulsive components.

The test methods account for the acoustical interaction between the wearer and the device using measurements of passive (REAT) and active microphone-in-real-ear (MIRE) measurements as specified in ISO 4869-1 and ISO 11904-1, respectively.

2 Normative references

The following documents are referred to in the text in such way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4869-1, ISO 4869-2, ISO 11904-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography