This second edition of CSA Standard 294.2 supersedes the first edition published in 1965. It covers ear plugs, ear muffs and helmet mounted hearing protectors. as did the 1965 edition. The sound attenuation requirements for these hearing protectors are quite different from those in the 1965 edition however, in that this Standard covers three levels of performance whereas the earlier edition covered only one. The sound attenuation reauirements in the first edition correspond roughly with those for Class A protectors in this Standard.
1.1 This Standard covers performance requirements for devices for personal hearing protectors.
NOTE: An outline of the needs for hearing protectors and various hearing-damage risk and protection criteria is included in Appendix A1.
1.2 This Standard applies only to complete factory assembled (or, in the case of imported protectors, distributor assembled) hearing protectors assemblies.