The method of testing a hearing protector to AS/NZS 1270:2002 is an involved process, and ensures that the protector will meet the requirements of workers in the real world.
In an approved laboratory, 20 naive subjects are individually tested with earplugs, and 16 subjects with earmuffs. They are provided with the hearing protector and printed instructions for fitting and are not given any assistance from the tester.
The test subject is asked to respond to different noise frequencies of where mathematically the SLC80 is calculated. The Class of the protector is determined by the SLC80.
The Howard Leight earplug and earmuff packaging display the protector’s SLC80 rating and class.