What are proximity clothing ratings?

• A. Reflects about 90% radiant heat; protects up to 200°F ambient and 2,000°F radiant heat.
• B. Reflects 50% radiant heat; protects up to 100°F ambient
• C. Reflects 99% radiant heat; protects up to 500°F ambient
• D. Absorbs radiant heat

Answer: (A)

Proximity clothing is designed to reflect radiant heat rather than absorb it, so its ratings focus on how much radiant heat is blocked and the temperatures it can tolerate in both ambient air and radiant exposure. The best choice states that the gear reflects about 90% of radiant heat and can protect the wearer in ambient conditions up to about 200°F while withstand­ing radiant heat up to 2,000°F. This matches how proximity gear is used: it creates a reflective shield so you can get close to a fire (like an aircraft fire) for a short time without being overwhelmed by radiant heat.

Choosing a rating that only reflects 50% would leave much more heat to the wearer and reduce protection. An ambient rating of only 100°F is far too low for the hot environments around aircraft fires. And a statement that the gear simply absorbs radiant heat contradicts the fundamental design of proximity clothing, which aims to reflect heat to keep the wearer cooler and safer. The combination of high radiant reflection and the ability to endure substantial radiant heat exposure is what makes proximity clothing effective for close, brief approaches to extreme heat sources.