Like other occupational exposure limits, the occupational exposure limit (OEL) or time-weighted average (TWA) can be modified for extended work shifts. When calculating exposure limits for an extended work shift, it is important to consider the health effects relating to noise exposure, as well as working an extended work shift. For example, a change in blood pressure may result from working an extended shift.
How can I determine my exposure limit?
Equal energy rule For instance, the International Organization for Standardization standard ISO 1999:2013 Acoustics — Estimation of noise-induced hearing loss and Ontario's A guide to the Noise Regulation under the Occupational Health and Safety Act both recommend using the equal energy when determining the time-weighted average (TWA) for a work shift: Adjusted exposure limit = Lexposure limit - 10 log (T/8), where T is the length of the work shift in hours."""