GB/T 14255-2015Household sewing machines head - Method of sound power levels of noise emitted (English PDF)

Foreword

This standard was drafted in accordance with GB/T 1.1-2009 given rules. This standard replaces GB/T 14255-1993 "Test Method for household sewing machine head sound power level", and GB/T 14255- Compared to 1993, the main changes are.

--- Original standard format prepared by the GB/T 1.1-2009 requested to prepare;

--- Original standard "Normative references" has been modified, citing the latest versions of these files. The standard proposed by China National Light Industry Council. This standard by the China Sewing Machinery Standardization Technical Committee (SAC/TC152) centralized. Drafting of this standard. National Sewing Machine Quality Supervision and Inspection Center, Shanghai Institute of sewing machines, sewing machine Zhejiang new shares leap Limited copies. The main drafters of this standard. Wang Weigang, Zhang Weiqing, Yepu Chang. This standard replaces the standards previously issued as follows:

--- GB/T 14255-1993. Household sewing machine head Test Method for the sound power level

1 Scope

GB/T 14255-2015 is the Chinese national standard on household sewing machines head - method of sound power levels of noise emitted, in the field of clothing industry. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 11 September 2015 by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of China, and has been in force since 1 April 2016. Classification: ICS 61.080, CCS Y17. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This standard specifies above a reflecting plane for the free field acoustic test environment, the illusion of a home sewing machine head envelope Measured on a measuring surface sound pressure level, sound power level has been calculated method results. This standard applies to household sewing machine head sound power level testing.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein Member. For undated references, the latest edition (including any amendments) applies to this document.

GB 3102.7-1993 Quantities and units of acoustics

GB/T 3241-2010 octave and fractional octave filters Electricity

GB/T 3785-2010 sound level meter, acoustic performance and test methods

GB/T 3947-1996 Acoustics Terminology JJG176-2005 acoustic calibrator verification procedures JJG188-2002 sound level meter verification procedures

3 Definitions and symbols

GB 3102.7-1993, terms and definitions GB/T 3947-1996 defined apply to this document.

4 Measurements and measurement error

4.1 Measurement Project Measurements include.

a) machine head noise A-weighted sound power level;

b) 1/1 octave band or 1/3 octave noise machine head band spectrum analysis (when requested);

c) the machine head noise directivity index (when requested).

4.2 Measurement error Measurement error should meet the following requirements.

a) engineering method. For radiation within the frequency range of 100Hz ~ 10000Hz uniform spectral density of the machine head, measuring A-weighted sound The standard deviation of power level should be less than 2dB. Measuring 1/1 octave band sound power level or the standard deviation of not more than one-third octave band Table

1 The requirements.

b) quasi-engineering method. For radiation in the frequency range 100Hz ~ 10000Hz uniform spectral density of the machine head, measuring A meter