By Alan S. Brown
Changes are coming to the personal protective clothing and respirators that protect first responders from chemical, biological, radiological and nuclear (CBRN) weapons.
The latest draft of NFPA 1994, Standard on Protective Ensembles for Chemical/Biological Terrorism Incidents changes the type of personal protective equipment (PPE) available to responders. It also aligns testing with procedures established for CBRN respirators by the National Institute for Occupational Safety and Health (NIOSH).
The new code promises to make CBRN protection affordable enough to store in all police cruisers and EMS vehicles, and to distribute to recovery workers on the periphery of an incident.
The new code also does a better job of matching PPE to tasks and threat levels, especially for responders who work long shifts outside the hot zone and during recovery. "When we developed the original standards, no one thought responders would wear [full protective gear] for two or three days, much less two or three weeks," explains Heinz Ahlers, acting chief of NIOSH's National Personal Protective Technology Laboratory's (NPPTL) Respirator Branch.
"People thought in terms of urban search and rescue, where four hours in PPE is a long time," he continues. "For four hours, the high level of protection has no downside. But if you have to wear a suit for shift after shift, you run into problems with heat and stress. The suit could actually pose more risk than the hazard you're mitigating."
The draft NFPA 1994 code addresses the problem by addition through subtraction: It eliminates the Class 1 vapor-protective ensemble. The PPE was always a type of anomaly. It closely resembled the NFPA 1991 hazmat PPE with CBRN option but lacked the hazmat suit's abrasion or flame resistance.
"If responders come up against an unknown hazardous chemical of high strength, they should be wearing a NFPA 1991 suit," says Wade DeHate, assistant chief of Hillsborough County Fire Rescue in Florida and a member of the NFPA 1994 technical committee.
"If they have a lesser threat or don't need vapor protection, then NFPA 1994 will let them pick a suit to fill the gap in protection, whether it's from vapor, liquid or particles."
NFPA 1994 gives responders three options to choose from. The most protective is a Class 2 suit, which is designed to use a self-contained breathing apparatus (SCBA). "It still looks like older [NFPA] 1994 Class 2, with liquid as well as some vapor protection," says Glenn Jirka, who chairs the NFPA 1994 technical committee. "It was designed for the guys who back up the hazmat team or people in high likelihood deployment areas."
Class 3 protective suits are worn with air-purifying respirators (APRs). Jirka expects them to be used in areas that are not immediately dangerous to life and health (IDLH). That includes the warm zone, perimeter, decontamination and after-incident cleanup where there is the potential for exposure to low concentrations of hazardous materials.
Class 3 suits may allow some breathability to reduce the amount of heat and moisture that builds up during work. The suits also offer limited vapor protection. There is a very definite trade-off between breathability and vapor protection. "While we want breathability, I'm not sure that it will really pan out in the field," he admits. Still, the door remains open to breathable garments as long as vendors meet the code's chemical- and biological-resistance levels.
The Class 4 PPE suits are new. Working with APRs, they protect against such airborne particulates as radioactive particles or anthrax spores. They were developed to answer a need that became apparent during the anthrax cleanup in Washington, D.C. At the time, responders had only vapor-protective PPEs for CBRN protection. Suit heat buildup and limited SCBA air supply shortened work shifts and prolonged the cleanup for months.
"People are looking for something more breathable," says Jirka. "If I have a particulate, do I need something to protect me from liquid splash or vapor? If a suit is over-engineered, it's actually making my work harder."
The NIOSH Connection
The new draft also proposes changes in how suits are tested. In the past, NFPA and NIOSH ran separate tests against different batteries of chemicals to certify PPE and respirators. Lack of consistency raised questions about how the suits would hold up in an emergency.
"We tried to match the levels of respiratory protection" with the rest of the suit, explains Jirka. "We don't want to over-engineer an ensemble so that it's never challenged before the respirator fails."
NIOSH sets high standards for SCBAs, says Steve Sanders, technical director of the Safety Equipment Institute. SCBAs must meet NFPA's 42 CFR Part 84 standard, NFPA 1981 for heat and flame resistance, plus stand up to live chemical warfare agents.
After consulting with the U.S. Army, NIOSH chose to test SCBAs against mustard and sarin nerve gas. Mustard sticks to clothing and penetrates over time. Highly volatile sarin seeps through any cracks or crevices in a seal. Both are highly corrosive and will degrade many plastics, including the silicone used to make many respirators.
NIOSH uses a manikin outfitted with sensors to determine whether any chemicals seep through the respirator, says Sanders. It also tests respirators on a variety of human subjects to ensure they fit without leaking.
APRs undergo similar testing for their ability to filter out toxic industrial chemicals (TICs) and chemical warfare agents.
New Respirator Standards
In addition to SCBAs and APRs, NIOSH has also published standards for escape respirators. Several are now undergoing certification testing, says Ahlers. They are designed for people in high-risk areas, such as guards in government buildings.
NIOSH is also examining certifying APR retrofits, though Ahlers says there is no real standard yet. "Any retrofit would have to come up to the original standard," he explains. "There are none in testing yet. Instead, people are focusing on certifying all-new APRs. If they qualify one, then they'll know what they need to change."
NIOSH is also writing a standard for CBRN powered APRs (PAPRs). The industry is resisting a new CBR standard while it still has to meet an older industrial standard. Instead, says Ahlers, it would like to see the new industrial and CBRN standards come out at the same time.
Finally, NIOSH would like to develop a standard for a closed-circuit SCBA. The units, which reprocess exhaled air and sweeten it with oxygen, have let mine rescue workers and U.S. Navy personnel work three-to-four-hour shifts.
Responders would love that type of productivity. Yet, they rebel against taking oxygen tanks into high-temperature workspaces. Any heat inside the suit is made worse by chemicals that heat the air as they purify it.
It may take some time to produce a closed-circuit SCBA standard. Meanwhile, NIOSH and NFPA are continuing to take what we have learned from 9/11 and apply it to the design of better protective equipment. HLR
Alan Brown is a contributing editor.