Each hearing protector is tested to determine its individual level of noise reduction when fitted correctly. Each protector has an SNR which is an abbreviation for Single Number Rating. The higher the SNR value of a hearing protection product, the higher the noise insulation provided.
To find out the protection figure required, the noise levels of the workplace must first be established. This is the calculated figure for the amount of potential protection the protector can provide when fitted correctly. For this, the noise levels need to be measured to determine the daily exposure levels, as well as any maximum or peak noises that might have an impact. A noise map is then established and then the required protection can be determined using the SNR method.