Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.
In general, the following instruments are appropriate for the measurement of occupational noise exposure (adapted from CSA Standard Z107.56-13, “Measurement of Noise Exposure”):
Impulse/Impact noise: A dosimeter or integrating sound level meter with a higher crest factor capability must be used for impulse or impact noise such as the sounds produced by a drop forge or blasting operations.
The following table is adopted from CSA Standard Z107.56-13, “Measurement of Noise Exposure”, clause 4.3 Instrument Selection. It may be used as a guide in selecting the most appropriate instrument.
|Dosimeter||All occasions, particularly when a worker cannot be accompanied or work has an unpredictable pattern. Most useful when work cannot be easily split into discrete activities.||Maximum sound level may exceed instrument range. Crest factor of sound may exceed instrument capability. Data collection is difficult to witness.|
|Integrating sound level meter||All occasions. Most useful when work can be easily split into discrete activities.||Maximum sound level may exceed instrument range. Crest factor of sound may exceed instrument capability where workers are exposed in an unpredictable fashion to different sound levels. However, in many cases a space average over the working area can provide a good estimate of the noise exposure of such people.|
|Sound level meter||Only useful when work can be easily split into discrete activities during which sound levels are steady.||Cannot adequately measure non-steady (> ±3 dB) or impulse sound.|
Note: This material is reproduced from CSA Standard CAN/CSA-Z107.56-13, “Measurement of Noise Exposure. While use of this material has been authorized, CSA shall not be responsible for the manner in which the information is presented, nor for any interpretation thereof.
As stated in Note (1) below the table, a dosimeter or integrating sound level meter with a higher crest factor capability must be used for highly impulsive noise such as the sounds produced by a drop forge or blasting operations. In the 2015 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, the ACGIH (American Conference of Governmental Industrial Hygienists) states, “By using the instrumentation specified by ANSI S1.4 – 1983 (R1997), “Specification for Sound Level Meters”, ANSI S1.25 -1991, “Specification for Personal Noise Dosimeters”, or IEC 804, “Integrating-Averaging Sound Level Meters”, impulsive or impact noise is automatically included in the noise measurement. The only requirement is a measurement range between 80 and 140 dB and the pulse range must be at least 63 dB.”
Note: “Pulse range” is the difference in dB between the peak level of an impulse signal and the root mean square or geometric average.
Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.
It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.
While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.