One of the first chemicals mentioned in the original request was H2S, or hydrogen sulfide. The ability of new sensors to detect specific chemicals has enabled further development to recognize other dangerous gases. “Now we have extended it to six to seven gases,” Ambal Jayaraman, principal engineer and researcher at TDA Research, told his SIGNAL Media. In addition to hydrogen sulfide, the list of target analytes includes carbon monoxide, chlorine, nitrogen dioxide, ammonia, phosphine, and hydrogen cyanide.
“Essentially, we have a material that changes color when exposed to a gas,” explains Matthew Chamot, principal mechanical engineer at TDA Research. “Based on that color change, we determine whether the gas we’re looking for is present and at what concentration.”
The device displays a color change to alert the handler, but the sensor also generates audible and vibrational notifications to alert first responders to the presence of a TIC.
The sensor has a platform that can be scaled up to 15 chemicals and weighs only 70 grams. It is also water and drop resistant, making it suitable for use in smoky environments. Notably, the portable devices cost about $200 each, which is significantly different from similar sensors on the market.
“The first experiments that were done were done at the Naval Research Laboratory,” Jones-Holt said. “They were able to get different TICs,” she continued. The report sent back to the TDA team helped them add an LED indicator that shows not only a color change, but also the type of chemical detected.
The following series of tests were conducted in conjunction with the Fairmount Fire Department to gain insight into the usability and effectiveness of firefighters’ everyday equipment. “We had them test the jackets and gloves and all the equipment,” Chamotte explained. “Probably the most difficult part was finding a good location to sample the gas accurately and not get in the way or hang around.”