NIST Finds Firefighter Radios May Fail During High-Temp Fires

October 27, 2006 // Published as a news service by IHS

The NIST study evaluated the general performance of portable radios at elevated thermal conditions, both to identify shortcomings and suggest standards for the radios.

The results will be used to develop test methods and recommendations for the National Fire Protection Association (NFPA) and other appropriate standards-setting bodies.

NIST fire engineers tested three representative portable radio models from three different manufacturers in a wind tunnel designed to simulate thermal conditions at three different degrees of intensity firefighters are equipped to withstand:

• Thermal Class 1, with a maximum temperature of 212 F (100 C) for 25 minutes.
• Thermal Class 2, with a maximum temperature of 320 F (160 C) for 15 minutes.
• Thermal Class 3, with a maximum temperature of 500 F (260 C) for five minutes.

Each of the test radios listed their maximum operating temperatures at only 140 F (60 C).

Results showed that one radio of the three samples would not transmit or receive after 25 minutes at 212 F, though it did begin working after a cooling off period. In another 15-minute experiment at 320 F, one radio went dead in just over eight minutes. The other two radios suffered significant performance problems - from transmission and reception shutdown to signal degradation or fluctuation. No test samples survived the Thermal Class 2 test and cool-down period.

Portable radios inside pockets or firefighter turnout gear fared much better. Researchers said all samples survived temperature tests at Thermal Class 1 and Thermal Class 2 maximum heats and times. Pocket-protected radios also survived Thermal Class 3, but exposed cords, speakers and microphones did not, effectively limiting the radios to Thermal Class 2 electronics.

NIST engineers suggested that small design changes on the speaker/microphones and cords could allow all the protected radios to reach a Thermal Class 3 rating.

The NIST study was conducted by the Building and Fire Research Laboratory for the NIST Office of Law Enforcement Standards, with funds from the U.S. Department of Homeland Security (DHS).

Source: National Institute of Standards and Technology (NIST)SDO.