Standards for Chemical, Biological, Radioactive, and Nuclear Protective Ensembles

NFPA 1994 provides standards for Chemical, Biological, Radioactive, and Nuclear ensembles.

NFPA 1994 Overview

NFPA 1994, Standard on Protective Ensembles for First Responders to CBRN Terrorism Events, 2007 Edition, sets design, certification, and minimum performance requirements for Chemical, Biological, Radioactive, and Nuclear (CBRN) protective ensembles for first responders to incidents involving CBRN terrorism agents, and for first responders exposed to victims or materials during assessment, extrication, rescue, triage, decontamination, treatment, site security, crowd management, and force protection operations at incidents involving CBRN terrorism agents. NFPA 1994 is an ensemble standard. Within the NFPA protective clothing project, an ensemble renders protection to the entire body; torso, arms, legs, head, hands, and feet. All NFPA 1994 garments are worn with respirators meeting CBRN requirements promulgated by NIOSH.

The standard was originally published in 2001 with three classes of protection. In that edition, Class 1 corresponded to Level A garments for high levels of skin vapor and liquid-splash protection. Class 2 corresponded to a high degree of liquid-splash protection but a lower level of vapor protection, while Class 3 of the 2001 edition was aimed solely at liquid protection. In the 2007 edition of NFPA 1994, the Class 1 CBRN designation was reserved to be covered in NFPA 1991, Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies. This was done to prevent industry confusion in the classification of CBRN protective ensembles. The protection for high vapor threats remains in NFPA 1991.

NFPA 1994 Protective Ensemble Details

The 2007 Edition of NFPA 1994 defines four classes of CBRN protective ensembles.

Class 1 Ensembles are Level A ensembles certified to the requirements of NFPA 1991, Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies, 2005 Edition. These are the most stringent CBRN barrier requirements, which include testing at 100% concentration of toxic industrial gases, and total surface coverage by liquid industrial and warfare chemicals. The physical property requirements for Class 1 are the highest among the NFPA chemical protective clothing standards.

Class 2 Ensembles are intended to provide limited protection to emergency first responder personnel at terrorism incidents involving vapor or liquid chemical hazards where the concentrations are at or above Immediately Dangerous to Life and Health (IDLH) levels, requiring the use of self-contained breathing apparatus (SCBA). These performance requirements are based on the anticipated threat a first responder may experience at a terrorism event employing chemical warfare agents, which are not as stringent as those applied to the Class 1 garments. The level of vapor protection required for Class 2 was based on the threat level used by National Institute of Occupation Health (NIOSH) in the CBRN certification of Self-Contained Breathing Apparatus (SCBA). The liquid chemical permeation threat is based on the military field clothing requirements of less than one-tenth total surface coverage. The physical property requirements are lower than those required for Class 1.

Two whole-garment tests have a major impact on the design of Class 2 garments. The 20-minute, whole-garment shower test demonstrates the liquid-penetration resistance of the entire garment under prolonged liquid contact. No liquid penetration is permitted. The Man-in-Simulant Test (MIST) evaluates the inward leakage of harmful chemical vapors into the garment. The performance levels established for the MIST Test in Class 2 are based on the level of anticipated vapor threat defined for the NIOSH certification of CBRN Self-Contained Breathing Apparatus (SCBA) at a threshold of skin reddening after mustard exposure or onset of muscle tremors upon exposure to sarin (agent GB).

Class 3 Ensembles are intended to provide limited protection to emergency first responder personnel at terrorism incidents involving biological hazards or radiological particulate hazards, where the concentrations are below Immediately Dangerous to Life and Health (IDLH) levels, permitting the use of air-purifying respirators (APR). The physical requirements and gas vapor permeation requirements for this class are lower than Class 2, while the liquid chemical permeation barrier requirements are essentially the same. The shower test is shortened to four minutes, and the MIST performance requirements are also lower. Class 3 also includes a Total Heat Loss (THL) requirement. THL relates to thermal conductivity of the fabric and rate of moisture diffusion through the garment material. The level set for Class 3 is comparable to that set for structural firefighting protective clothing.

Class 4 Ensembles are intended to provide limited protection to emergency first responder personnel at terrorism incidents involving biological hazards or radioactive particle hazards, where the concentrations are below Immediately Dangerous to Life and Health (IDLH), permitting the use of air-purifying respirators (APR). Class 4 contains no chemical barrier requirements, but the standard allows products to be certified as compliant to Class 4 and either Class 2 or Class 3. In Class 4, particle barrier is evaluated on the basis of a whole-garment particle inward leakage test. Class 4 garments are not subjected to a shower test, but the garment materials must resist penetration of liquid-borne virus under pressure. Class 4 also contains THL requirements that are two-and-a-half times greater than what is stipulated for Class 3. The physical requirements for Class 4 are comparable to those found in Class 3.

In all three NFPA 1994 classes, the types of tests are similar to those found in NFPA 1991 and NFPA 1992, except that the levels of acceptable performance are lower. And, as done in NFPA 1991 and NFPA 1992, the garment material, footwear, gloves, and head protection are evaluated, as well as seams and closures. All garments certified to the NFPA 1994 classes must be tested with each of the CBRN-approved respirators that the end-users intend to use with those garments.

How NFPA 1994 differs from other NFPA standards

NFPA 1994 is not a hazardous materials response standard. The requirements of NFPA 1994 were set with a specific set of tasks in mind. Garments that only meet the minimum requirements of Class 2 or 3 of NFPA 1994 do not have the level of chemical permeation barrier generally associated with garments generally worn during hazardous materials response. Class 2 NFPA 1994 garments are only tested for permeation against five liquid chemicals at a surface loading of 10 g/m2 and two gases at 350 ppm. By comparison, NFPA 1991 requires testing at full surface coverage against 19 full strength industrial liquids, six gases at 100% concentration, and two chemical warfare agents. Permeation testing conducted on hazardous materials protective materials are generally conducted with a broad range of liquid chemicals. If an organization plans to use NFPA 1994–compliant garments for hazardous materials response, it should determine if the product has a sufficient permeation barrier against a wide range of chemicals at total surface coverage.

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