Which term is commonly used to denote the exposure limit for laser safety?

• A. MPE
• B. PEL
• C. TLV
• D. ALARA

Answer: (A)

The exposure limit used in laser safety is the Maximum Permissible Exposure. This term defines the highest level of radiant energy (in terms of irradiance or radiant exposure) at a given wavelength and exposure duration that is considered non-hazardous. It’s the benchmark used to judge safe operation, guide protective measures, and determine hazard zones in laser safety standards like ANSI Z136.1 and IEC 60825. The other terms aren’t specific to laser safety limits: PEL pertains to workplace limits for chemical/ractor exposures, TLV comes from ACGIH for various agents, and ALARA is the principle to minimize exposure rather than a strict numeric limit.