In January, 2007, the government of Ontario, Canada, announced changes to the Occupational Health and Safety Act, introducing stricter limits for noise exposure in the workplace. The changes affect virtually all workplaces in the Province. The requirements will come into effect on July 1, 2007, and will toughen the regulation in three ways.
First, the limit for a worker’s daily exposure to noise will be reduced from 90 dBA to 85 dBA. Second, the “exchange rate” will be reduced from 5 dBA to 3 dBA. This means that for every increase in sound level of 3 dBA the allowable exposure time for the worker is halved. (Previously, an increase of 5 dBA reduced the allowable exposure by half, which was less stringent.) Third, the changes to the regulation will make explicit the responsibility to implement engineered noise control measures where sound levels exceed 85 dBA.
While these changes will be beneficial in terms of reducing the risk of noise-induced hearing loss in the workplace, the burden on some industrial noise makers may be onerous. A decrease in sound level of just 5 dBA – from 90 dBA to 85 dBA, for example – requires a 47% reduction of acoustic energy, because of the logarithmic nature of sound. And, with the new rules, it will be less acceptable to resort to the use of personal hearing protection as a method of reducing a worker’s exposure to noise. Instead, the new regulations require that acoustical engineering be investigated to develop industrial noise control and vibration control measures. Hearing protectors will only be accepted as a fallback when the company can demonstrate that engineered noise control measures are not feasible.
HGC Engineering will be co-authoring with audiologist Marshall Chasin an article in the May/June 2007 issue of Engineering Dimensions magazine, discussing these changes to the legislation and the increased responsibilities upon workplace managers. Watch for it!
