BS ISO 9296:2017 pdf download – Acoustics — Declared noise emission values of information technology and telecommunications equipment
1 Scope
This document is applicable to information technology and telecommunications equipment.lt specifies:
a) for a batch of equipment, the method for determining the following values:
– the declared mean A-weighted sound power level, LwA,m;
– the declared mean A-weighted emission sound pressure level, LpA,mi
– the statistical adder for verification, Kv;
– the statistical upper limit A-weighted sound power level, LwA,c;
b) how acoustical and product information is to be published electronically or in hard-copy format in
technical documents or other product literature supplied to users by the manufacturer or declarer;c)the method for verifying the noise emission values that are declared by the manufacturer or
declarer.
NOTE The terms “manufacturer”and “declarer”are used in this document to represent any entity thatprovides product noise emission information. For instance,a product supplier or importer who does notmanufacture the hardware, but offers noise emissions information, is also referred to a manufacturer or adeclarer as applicable, in this document.
The uniform methods in this document use the noise emission data obtained in accordance withIS07779, and the declaration and verification procedures detailed in IS0 48714 and IS0 7574-4.6]The basic noise emission values to be declared are the declared mean A-weighted sound power levels,LwA,m. Optionally, the declared mean A-weighted emission sound pressure levels at the operatoror bystander positions， LpA,m. can be declared. These are arithmetic mean values based uponmeasurements on a random sample of equipment of the batch, in accordance with IS0 7779.
For verification purposes, an additional quantity is required to be declared: the statistical adder forverification, K.. This is a quantity that is added to the declared mean A-weighted sound power level,LwA,m, and used in the verification section of this document to provide a consistent and predictableprobability of acceptance for the batch of equipment.
The declared mean A-weighted sound power level for the batch of equipment permits comparison ofnoise emissions between different products and permits predictions of installation or work-place noiseimmission levels, as described in ECMA TR/27.[9]
Although the most useful quantity for calculating immission levels due to one or more noise sources isthe A-weighted sound power level of the individual source(s), the A-weighted emission sound pressurelevel may also be useful in estimating the immission level in the immediate vicinity of an isolated pieceof equipment.
To avoid confusion between sound power levels and emission sound pressure levels, the declaredmean A-weighted sound power level, LwA,m, is expressed in bels (B) and the declared mean A-weightedemission sound pressure level, LpA,m, is expressed in decibels (dB).
2 Normative references
The following documents are referred to in the text in such a 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.
ISO 7779, Acoustics — Measurement of airborne noise emitted by information technology and telecommunications equipment
3? Terms? and? definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1? General? definitions
3.1.1
information technology and telecommunications equipment
ITT equipment
equipment for information processing, and components thereof, used in homes, offices, server installations, telecommunications installations or similar environments
[SOURCE: ISO 7779:2010, 3.1.3]
3.1.2
batch of equipment
lot of equipment
number of units of information technology or telecommunications equipment intended to perform the same function produced in quantity, manufactured to the same technical specifications and characterized by the same declared noise emission value
Note 1 to entry: The batch may be either an entire production series or a portion thereof.