boundary layer The layer of fluid adjacent to a physical boundary in which the fluid motion is significantly affected by the boundary and has a mean velocity less than the free stream value
permissible exposure limit An exposure limit that is set for exposure to an hazardous substance or harmful agent and enforced by OSHA (Occupational Safety and Health Act) as a legal standard. It is based on time-weighted average concentrations for a normal 8-hour work day and 40 hour work week
regulation on maximum permissible limits A body of rules or orders prescribed by a government or an international organization or treaty establishing levels of hazardous materials in the environment or in ingestible substances beyond which human exposure is deemed health-threatening
limit value A workplace exposure criterion or standard that determines if a facility or building has a concentration of a substance to which most workers can be exposed without harmful or adverse effects
