Glossary
Excursion Limit
A short-term (commonly 30-minute) exposure limit, set above the 8-hour TWA PEL, that cannot be exceeded at any time.
The excursion limit is a short-term exposure ceiling that applies in addition to the 8-hour PEL. For asbestos under 29 CFR 1926.1101, the excursion limit is 1.0 fibers per cubic centimeter of air, averaged over a 30-minute sampling period.
The excursion limit acknowledges that short, intense exposures can be harmful even when the 8-hour TWA stays within the PEL. Worker monitoring has to capture short-term peaks, not just full-shift averages.
A worker exposed above the excursion limit, even briefly, triggers controls regardless of where the full-shift exposure ends up.