What is the maximum allowable surface temperature in Fahrenheit for exposed skin due to incident radiation from a flame effects display?

• A. 109°F
• B. 111°F
• C. 112°F
• D. 105°F

Answer: (B)

When evaluating the risk from radiant heat in a flame effects setup, the safety goal is to keep any skin surface that could be exposed to radiant energy at a temperature low enough to prevent burns during typical exposure times. The limit used in standard flame effects safety guidance is 111°F (about 44°C). This temperature is chosen because it represents a conservative cap: skin exposed to radiant heat at or below this level is unlikely to suffer burns with the brief contact times that can occur around performances, while allowing enough practicality for the effect to look convincing.

Radiant heat from a flame can heat skin directly without the surrounding air getting very hot, so controlling the surface temperature of exposed skin is about limiting heat transfer to that skin area. The value of 111°F balances safety with operational practicality, which is why it’s the commonly cited maximum in these contexts. The other nearby numbers would either be more restrictive than necessary or less protective, making 111°F the best fit among the options.