A revision to the fire-protection standard that addresses indoor use of fuels brings chemical handheld detectors back into focus.
Last year, a chemical accident at a 425,000-square-foot ConAgra plant in Garner, N.C., exposed about 300 workers to toxic fumes and severe burns. The Chemical Safety and Hazard Investigation Board found that the accident was caused by improper indoor gas-purging and encouraged that the practice be restricted, said Guy Colonna, a National Fire Protection Association (NFPA) division manager. In response to the findings, the NFPA moved to strengthen current gas-purging safety requirements in NFPA 54, known as the National Fuel Gas Code.
The NFPA wants to require the discharge of purged gas to be directed outdoors and has identified specific requirements that must be met during the purging process. Part of this mandate is that companies must deploy a portable gas detector to determine when the purging process is complete. Previously they relied on smell, Colonna said.
“They will now be required, at the dispatch point, to use calibrated atmospheric monitoring devices capable of detecting the appropriate concentrations of purged gas,” he said.
Most chemical companies already have such detectors on site for use in high-risk areas, said Bob Durstenfeld, Rae Systems' senior director of corporate marketing. Rae Systems sells to both private and public clients, and he said safety regulations and common-sense are two reasons to keep such systems on hand.
The company recently released the AreaRAE Inert that can be used for gas detection in an inert environment. According to Durstenfeld, a standard off-the-shelf chemical detector is designed to work in an atmosphere with at least 20% oxygen But the AreaRAE Inert was designed for low-oxygen atmospheres — about 8% oxygen — that may initiate a chemical reaction, like an explosion.
“An inert environment is a space that is known to be lethal,” Durstenfeld said, adding that the Inert is ideal for confined-space entry where oxygen has been displaced by an inert gas, such as nitrogen.
The Inert has a built-in pump that lets users monitor the atmosphere from up to 100 feet away by drawing an air sample through the attached tubing. It can be equipped with up to five sensors: a photoionization detector, a lower explosive limit sensor, a solid polymer electrolyte oxygen sensor and two addition toxic-gas sensors. In addition, it is packaged in a weather-resistant, stainless-steel housing.
The device has a wireless range of up to 2 miles. The ability to transmit data to remote experts for monitoring and evaluation is a key selling point, Durstenfeld said. “People want to see data in real time,” he said.
Meanwhile, Thermo Fisher Scientific, formally Ahura Scientific, offers handheld chemical detectors designed to identify unknown solids and determine whether they are toxic, said Duane Sword, a vice president of marketing. The company recently released two new offerings: the FirstDefender RM and RMX. The devices can be used by industrial or public-safety clients, Sword said.
The RM is the next generation of the company's FirstDefender product line. It is lighter at 1.8 pounds but still houses a library of more than 10,000 chemicals, such as those used in explosives. It can be used in point-and-shoot mode or via the integrated vial holder to detect chemicals in an average of 30 seconds, Sword said.
The RMX version is deployed as an add-on to a wirelessly controlled robot. It weighs 2 pounds and can be operated either in handheld mode or attached to the gripper arm of a tactical robot, Sword explained. It was developed in partnership with robot manufacturers QinetiQ North America and iRobot Corp. As a result, the detector can be connected to robots via an RS232 port and its findings can transmitted over a wireless network to a facilitator's laptop, he said.
“Such remote operation lets users execute their response missions with a greater level of safety,” Sword said.