These jurisdictions also do not allow unprotected exposures for sound levels that exceed 90 dBA. dBA Lex means the level of a worker's total exposure to noise in dBA is averaged over an entire workday and adjusted to an equivalent eight-hour exposure. The regulations in these jurisdictions indicate that over an exposure limit of 85 dBA Lex or an “at any time” sound level limit of 90 dBA, the employer is required to provide hearing protection, train workers and implement audiometric testing. The regulations in these jurisdictions do not specify a value but reference the ACGIH TLVs.Ĥ. The exact figures vary slightly, but generally the regulations in which the exchange rate is 5 dB permit 10,000 impulses at a peak pressure level of 120 dB 1,000 impulses at 130 dB 100 impulses at 140 dB, and none above 140 dB.ģ. A common approach is to limit the number of impulses at a given peak pressure over a workday. Noise regulations in several jurisdictions treat impulse noise separately from continuous noise. The equivalent sound exposure level (L ex) takes impulse noise into account in the same way as it does that for continuous or intermittent noise. When 3 dB exchange rate is used, generally there is no separate regulation for impulse/impact noise. For more information about continuous, impulse and impact noise, please see Noise - Basic Information.Ģ. Maximum Permitted Exposure Level for 8 Hours: dB(A)ġ. Jurisdiction (federal, provincial, territorial) What are the noise exposure limits in Canadian jurisdictions? The table below shows the criterion levels (i.e., maximum permitted exposure levels for 8 hours) and the exchange rates used in different Canadian jurisdictions. This is precisely the case if the 3 dBA exchange rate is used. It follows, then, that the allowable time should be halved for every 3 dBA increase in sound level. They argue that it is logical that if the sound level is doubled, then the allowable exposure time should be cut in half. Most experts recognize the 3 dB rule as more logical. With the 5 dBA exchange rate, it is one hour. For example, the maximum permitted duration for a 100 dBA noise exposure in the 3 dBA exchange rate is 15 minutes.

The 3 dBA exchange rate is more stringent. There are two types of exchange rates currently in use: 3 dBA exchange rate or the '3 dB rule,' and 5 dBA exchange rate or the '5 dB rule.' These two exchange rates, with criterion levels of 85 dBA and 90 dBA, give two different sets of exposure guidelines, as Table 1A and 1B show. The allowed maximum exposure time is calculated by using an exchange rate, also called a 'dose-trading relation' or 'trading ratio.' The exchange rate is the amount by which the permitted sound level may increase if the exposure time is halved. As the sound level increases above the criterion level, Lc, the allowed exposure time must be decreased.

Decibel exposure chart