Employees are required to be protected from arc exposures exceeding how many cal/cm2?

• A. 1 cal/cm2
• B. 5 cal/cm2
• C. 10 cal/cm2
• D. 2 cal/cm2

Answer: (D)

Arc flash energy is measured in cal/cm^2 and drives what PPE is required. The point at which protection must step up is 2 cal/cm^2. That means if the potential arc exposure could exceed 2 cal/cm^2, workers must wear arc-rated PPE rated for at least that energy, including appropriate flame-resistant clothing, a face shield or hood, and insulated gloves. Exposures at or below 2 cal/cm^2 can often be addressed with basic flame-resistant clothing, but once the energy could surpass 2 cal/cm^2, higher-level arc-rated protection becomes necessary. In practice, you determine the incident energy through hazard analysis or standards tables and ensure the PPE matches or exceeds the calculated energy, using additional controls to reduce exposure whenever possible.