Is Your Team Protected?

Not all certification standards are created equal, not even from the NFPA.

Hazmat teams at fire departments, industrial companies, and military units have enough to worry about in hazardous situations without having to be concerned about whether their hazmat suits fully protect them. In an effort to help hazmat professionals ensure their teams are fully protected, below are answers to some of the most frequently asked questions about chemical protective suit standards.

Q: Who sets the standards for certification of hazmat suits?

A: For more than 100 years, the National Fire Protection Association (NFPA) has been the leading authority on fire protection and safety and has developed many of the standards that hazmat and safety professionals rely on to keep themselves and their organizations out of harm's way. However, NFPA standards can be confusing, and industry knowledge about the importance of purchasing NFPA-certified hazmat suits is sometimes lacking.

Q: What specific NFPA standards are relevant for hazmat suits?

A: With regard to hazmat suits, the NFPA 1991 standard (Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies, 2005 ed.) defines the highest level of protection.

Industry professionals also look to the NFPA 1994 standard (Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents, 2007 ed.), which is less stringent than NFPA 1991.

Q: What are some of the requirements for NFPA certification?

A: NFPA certification represents the highest standard in hazmat suit protection on the market because suits must pass the organization's rigorous tests of flame, physical, and chemical resistance to achieve certification.

The flame resistance test consists of a flame source that touches the outside of a material with a three-second initial exposure (with no ignition allowed) and a 12-second subsequent exposure. To meet NFPA 1991 requirements for adequate protection, for example, the material must display no burning after 10 seconds, no burning greater than 4 inches, and no melt or dripping.

The primary chemical test method involves preconditioning the outside surface of the suit material by abrasion and flexure followed by chemical exposure. The key point is to understand that the suit materials are subjected to damaging conditions prior to chemical exposure.

Specific requirements are different, however, between the two NFPA standards. Between the highly specific wording within the NFPA standards and the inconsistency with which some manufacturers communicate the difference between them, understanding the right level of certification can be tricky.

Q: What are some of the performance differences between suits certified to the different standards?

A: Even though many NFPA 1994 Class 2 ensembles visually resemble those certified to the NFPA 1991 standard, they don't offer the same level of protection. In general, NFPA 1994 requirements are looser than NFPA 1991 requirements for chemical testing, vapor tightness, flame resistance, and physical properties.

Distinct differences in performance are gas-tight integrity and flame resistance tests. To meet certification for NFPA 1991, hazmat suits must maintain at least 3.2 inches H2O during the gas-tight integrity test, and flame resistance of less than 10-second afterflame with no melt or drip after 12 seconds. By comparison, NFPA 1994 requirements for both of these performance characteristics are not applicable and do not require testing.

Other performance measurements also signal differences between the two certification levels. The burst strength for the suits under NFPA 1991 is mininum 45 pound force (lbf), while for NFPA 1994 it is minimum 35 lbf. Similarly, the puncture tear resistance and seam-breaking strength requirements for NFPA 1991 certification are almost two times greater than NFPA 1994 requirements. The closure breaking strength is similarly disproportionate for each certification standard as well.

For abrasion preconditioning, NFPA 1991 certification requires 80 grit (coarse) for 25 cycles, while NFPA 1994 requires only 600 grit (very fine) for 10 cycles.

This is followed by chemical testing, in which the NFPA 1991 standard requires hazmat suits to withstand 19 different toxic industrial chemicals, six different gases, and two warfare agents. By contrast, the NFPA 1994 standard requires suits to withstand three toxic industrial chemicals, two gases, and two warfare agents. In the 2007 edition of NFPA 1994, the permeation requirements were loosened. Rather than measuring for a maximum allowable detection level, the standard now allows for a cumulative amount of chemical to permeate.

Q: Do all NFPA 1991-certified suits provide the same level of protection?

A: One difference among NFPA 1991-certified suits is flash fire protection, which only some hazmat suits provide. The flash fire requirement is optional for NFPA 1991 certification and requires an additional test. During this test, a suit is positioned inside a propane-filled flash chamber and must sustain a 6-to-8-second flash fire exposure with an after-flame of no more than two seconds. After exposure, the suit must maintain airtight integrity and visual acuity in order to fully meet the requirements.

Additionally, some hazmat suits certified to the NFPA 1991 standard meet the requirements only when heavy aluminized overcovers are worn. Basically, they require that a suit be worn over a suit. When using these dual-layered suits, some hazmat users choose not to wear the over-covers either, because their purpose is not understood or due to awkwardness and inconvenience. This leaves them potentially and unknowingly unprotected.

Q: Where can industry professionals go for additional information?

A: We at Saint-Gobain Performance Plastics put together a certification booklet to help people out, and it's available free of charge on our Web site. The NFPA also publishes the full text of its standards on its Web site for a fee.

This article originally appeared in the August 2009 issue of Occupational Health & Safety.

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