圣者
精华
|
战斗力 鹅
|
回帖 0
注册时间 2012-5-24
|
本帖最后由 shahito 于 2014-10-11 13:25 编辑
我有点言重了,其实有点像是偷换概念
看看美国官网,你那是European的。
http://solutions.3m.com/wps/portal/3M/en_US/3M-PPE-Safety-Solutions/Personal-Protective-Equipment/Products/Product-Catalog/~/3M-Peltor-Earmuffs-X-Series?N=3294529207+3294326315+5023508+8693072&rt=rud
复制了段:
Symbol Definition Where Used
NRR Noise Reduction Rating United States
SNR Single Number Rating European Union
NRR [Noise Reduction Rating] – This rating is used in the United States, and is accepted for use in a variety
of other countries. The current range of NRRs available in the U.S. market extends from 0 to 33 decibels.
SNR [Single Number Rating] – This rating number is used by the European Union and affiliated countries.2
Tests are conducted at independent testing laboratories, using test frequencies which are slightly different than
those used for the NRR rating. In addition to an overall rating, the SNR further rates protectors in terms of the
particular noise environments in which they will be used – H for high-frequency noise environments, M for
mid-frequency, and L for low-frequency. Note that the HML designation does not refer to noise level, rather the
spectrum of the noise. Forexample, a protectormight be designated with SNR 26, H=32, M=23, L=14.The estimated
attenuation changes according to the noise spectrum of the environment in which the protector is to be worn.
|
|