What does NHZ stand for in laser safety terms?

• A. The zone where exposure always stays under MPE
• B. The area within a laser workplace where exposure could exceed MPE
• C. The zone outside the facility
• D. The zone where the beam is not used

Answer: (B)

Nominal Hazard Zone refers to the region around a laser where exposure to the laser radiation could exceed the Maximum Permissible Exposure under the stated operating conditions. The size and shape of this zone depend on the laser’s wavelength, power, beam geometry, focusing, and exposure duration. Inside the NHZ, access and protective measures are required because exposure could be hazardous; outside, exposure is expected to remain below the MPE under the same conditions. The other options describe zones that are either always safe or not relevant to where the beam presents a hazard.