Clearing The Air On Hazmat Suit Certification Standards

Hazmat professionals form a unique fraternity of men and women who rely heavily on one of their most essential tools – their hazmat suits – for safety and protection. On any given day they could be confronted with toxic chemicals, noxious gases or the intense heat of flames. Their uniforms must be rugged and durable, yet advanced enough to allow them to perform their job duties and return home safe and sound to their loved ones.

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 emergency service workers rely on to keep them out of harm’s way. The organization’s certification is the gold standard in fire and hazmat safety and is often required for any local, state or federal procurement of fire safety equipment. 

Points Of Misinterpretation

However, NFPA standards can be confusing, and industry knowledge about the importance of purchasing NFPA-certified hazmat suits is sometimes lacking. 

One of the main points of misinterpretation involves two NFPA hazmat protective ensemble standards. The 2005 edition of the NFPA 1991 Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies defines the highest level of protection offered by the organization. Ensembles certified to the less stringent 2007 edition of the NFPA 1994 Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents often visually resemble those certified to the NFPA 1991 standard.

A Suit Over A Suit

Some hazmat suits certified to the 1991 standard only meet the requirements 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 overcovers – either because their purpose is not understood or due to awkwardness and inconvenience, leaving them potentially and unknowingly unprotected. 

Between the highly specific wording within the NFPA standards and inconsistency with which some manufacturers communicate the differences between them, understanding the right level of certification can be a tricky proposition.

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

There are many tests that every hazmat suit must undergo before being certified. 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, the material must display no burning after 10 seconds, no burning greater than four inches and no melting 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.

Not all NFPA 1991-certified hazmat suits provide flash fire protection. The flash fire requirement is optional. During this test, a suit is positioned inside a propane filled flash chamber and must sustain a 6-to-8-second flash exposure with an afterflame of no more than two seconds. After exposure, the suit must maintain airtight integrity and visual acuity in order to fully meet the requirements.

Significant Differences

To really understand what level of protection a hazmat suit offers, it is important to look for the NFPA certification before making any purchase. Also, hazmat professionals must make sure their protective suits are worn according to certification standards. For dual-layered protective suits, discarding the overcover may expose the user to dangerous conditions. 

To the untrained eye, many NFPA 1994 Class 2 ensembles are similar to those certified to NFPA 1991. However, a closer look reveals very significant differences in performance.

Gas Tight Integrity

NFPA 1994 protection level requirements are less stringent than NFPA 1991 requirements for chemical testing, vapor tightness, flame resistance and physical properties. 

Distinct differences in performance are the gas tight integrity and flame resistance tests. To achieve NFPA 1991 certification, hazmat suits must maintain at least 3.2 inches H2O (a unit of pressure) during the gas tight integrity test, which demonstrates that the suits are airtight. During this test, suits are filled with 4 inches H2O, and pressure is monitored for four minutes using a pressure gauge because any leakage from the suit will result in a pressure drop. Hazmat suits must also maintain flame resistance of less than 10-second afterflame with no melt or drip after 12 seconds. By comparison, NFPA 1994 does not require either gas tight integrity or flame resistance tests.

Other performance measurements also signal differences between the two-certification levels, with suits certified to NFPA 1991 requiring stronger materials than those certified to NFPA 1994. 

Specifically, the burst strength for the suits under NFPA 1991 is a minimum of 45 lbf (pounds per force), while for NFPA 1994 it is a minimum of 35 lbf.

Similarly, the puncture tear resistance and seam-breaking strength requirements for NFPA 1991 certification are greater than 11 lbf/inch and 15 lbf/inch, respectively, compared to NFPA 1994 requirements, which stand at a minimum of 7 lbf/inch for each measurement. The closure breaking strength is similarly disproportionate for each certification standard as well. 

Chemical Permeation

As if these disparities were not enough to clearly indicate the strong performance edge of NFPA 1991 certification, a look at the chemical permeation testing requirements for each certification further widens the margins. For abrasion preconditioning, NFPA 1991 certification requires that the suit material be subject to contact with sandpaper of 80 grit (coarse) for 25 cycles with an oscillating drum, while NFPA 1994 only requires 600 grit (very fine) for 10 cycles. 

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. 

Emergency personnel have enough to worry about in hazardous situations without having to be concerned about whether their hazmat suits fully protect them. While at first glance, suits certified to the NFPA 1994 standard may appear similar to those developed to meet the far more stringent NFPA 1991, a closer look reveals the vast differences in protection between the two. 

Understanding the differences between the NFPA standards is one way to ensure that you and your team are fully protected. Hazmat professionals deal with plenty of unknowns; being certain about hazmat suit certification is one worry they can easily avoid.

Editor’s Note: Peter A. Kirk II is the product manager of the ONESuit line of chemical and biological protective products at Saint-Gobain Performance Plastics in Merrimack, N.H. He has an extensive technical background in protective clothing and structures and is responsible for product development and marketing strategies. He earned an MBA from Franklin Pierce College and a bachelor’s degree in mechanical engineering technology from the University of Maine.

More Fire Apparatus Current Issue Articles
More Fire Apparatus Archives Issue Articles

No posts to display