Protective clothing and equipment manufacturers have been making tremendous strides in developing performance-based products, and nowhere is that more evident than in the Chemical, Biological, Radiological and Nuclear world.
Gone are heavy, heat stress-inducing Level A suits made of butyl or neoprene rubber. In their place are single- or limited-use suits made from layered fabrics like Gore Chempak in combination with DuPont Nomex with a fluoropolymer film between the layers. And there are new chemical barrier fabrics, such as DuPont Tychem, which are designed specifically for protection against toxic corrosive gases, liquids and solid chemicals.
The primary guidance for our responses to hazardous substance releases, which now include CBRN, continues to come from OSHA's Hazardous Waste Operations and Emergency Response (HAZWOPER) Standard (29 CFR 1910.120(q)).
CBRN veterans are likely familiar with terminology such as: hot, warm and cold zones; Level A suits for vapor protection; and Level B suits for splash protection. These terms arose from the HAZWOPER standard and the initial approach used by OSHA to characterize the different protective ensembles available at the time. Remember, we are talking the early 1980s, the dawning of the hazmat era in the fire service.
The short coming of this approach is that OSHA ratings only took into account how a suit was designed to interact with the respirator — fully encapsulated or not — and did not factor in any performance requirements related to chemical permeation of the ensemble.
NFPA came on the scene with NFPA 1994: Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents. This standard establishes the minimum requirements for the design, performance, testing, documentation, and certification of protective ensembles and ensemble elements for protection of emergency first responders certified at the hazmat operations level who engage in rapid rescue operations in the hot zone and defensive tactical operations in the warm zone at CBRN events
Although there is no official relationship between OSHA and NFPA, the following provides a comparison between the various NFPA 1994 classes OSHA levels for PPE.
OSHA Level A (no NFPA equivelant) is for airborne and liquid concentrations are at or above IDLH requiring the highest level of protection for both respiratory system and skin. User and SCBA are fully encapsulated within the suit.
OSHA Level B/NFPA Class 2 is for airborne concentrations are at or above IDLH requiring the highest level of protection for respiratory system. Liquid concentrations are below IDLH allowing for a lesser level of skin protection. User is encapsulated within the suit, while the SCBA is contained outside. Many manufacturers have ceased production of their non-encapsulated models in favor of the increasingly popular full-encapsulated Class 2 ensemble.
OSHA Level C/NFPA Class 3 is for airborne and liquid concentrations are below IDLH allowing for a lesser level of respiratory and skin protection. User is encapsulated within the suit and using an air-purifying respirator or powered air-purifying respirator. It provides the appropriate level of protection for personnel engaged in defensive tactical operations in the warm zone as well as decontamination procedures and medical response to victims exposed to CBRN threats. These recently revised requirements also specify that garments must conform to total heat loss requirements of 200 W/m2.
OSHA Level D/NFPA Class 4 is for nuisance, non-chemical powder contamination and do not address chemical agent or toxic industrial chemical protection. Use has basic shield PPE such as coveralls, disposable outer boots and safety glasses. Dust filter required for radiation contamination. Class 4 garment materials must demonstrate a total heat loss requirement of 450 W/m2.
NFPA 1991 Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies was formerly included in NFPA 1994 as Class 1. It determines protection for those personnel trained and certified to hazmat technician or specialist level who engage in offensive operations in the hot zone.
NFPA 1991-compliant garments must totally encapsulate the wearer and breathing apparatus to provide the highest level of liquid, vapor and particle protection for a range of HAZMAT emergencies. They are certified as ensembles that include gloves, boots and an outer abrasion-resistant cover.
Storage and care for CBRN PPE
When we hear the term shelf life, we typically think of products or materials that can go bad, like milk, meat, IV fluids or medications. The good news concerning today's CBRN protective ensembles is that the chemical barrier fabrics used in their construction have not been shown to age.
There is currently no accepted industry standard for determining the lifecycle for the current generation of CBRN PPE. One manufacturer reports that comparisons between its current suits and those that have been stored for 15 years showed no evidence that the materials had lost their protective characteristics.
Properly storing CBRN PPE, away from direct sunlight and preferably in a cool, dry location that is not subjected to extreme hot or cold conditions, should ensure that the PPE will be ready for service whenever the need arises.