Rethink Level A

Frequently Asked Questions


Can NFPA protection standards be compared to OSHA/EPA levels?

Yes. The OSHA levels were first established in the 1980s by the U.S.

Environmental Protection Agency and then codified into OSHA 1910.120 for

both hazardous waste site operation and emergency response. These

levels describe how ensembles look in relation to the threats to both skin

and the respiratory system but did not define performance. NFPA standards

for hazardous materials protective clothing were introduced in the early

1990s to define minimum levels of protection and performance. The NFPA

standards have evolved to keep up with current and emerging threats and

the table below shows how ensembles certified to NFPA standards compare

to the OSHA and EPA levels.

Does OSHA require the use of Level A ensembles for response to

unknown materials?

No. OSHA designates Level B PPE as the appropriate ensemble for initial entry.

Title 29, part 1910, subpart 120 (29 CFR 1910.120), states “If the preliminary

site evaluation does not produce sufficient information to identify the hazards

or suspected hazards of the site, an ensemble providing protection equivalent

to Level B PPE shall be provided as minimum protection, and direct reading

instruments shall be used as appropriate for identifying IDLH conditions.”

Do Level A suits need to encapsulate the SCBA in addition to the wearer?

No. Level A ensembles differ from Level B ensembles by providing a higher

level of skin protection for preventing absorption of hazardous materials

as defined in OSHA 29 CFR 1910.120. The protection of responder’s skin

from exposure to hazardous materials is the key attribute that defines Level

A performance, not total encapsulation or inflation testing. Suits certified to

NFPA 1994 for Class 1 are considered Level A regardless of whether they are

totally encapsulating. OSHA 29 CFR 1910.120 requires totally encapsulating

suits to be capable of maintaining positive pressure (typically demonstrated

by inflation or pressure testing suits) and preventing inward vapor leakage of

more than 0.5%.

Are there better tests for qualifying the performance of protective

ensembles other than inflation testing?

Yes. While inflation testing of totally encapsulating ensembles is a relatively

easy test to perform, it is only a suggested test within the non-mandatory

Annex A of the OSHA 1910.120 regulations. While inflation testing is

sensitive to small leaks, it is performed statically with the suit exhaust

valves closed off and is not sufficient by itself to determine if the ensemble

is safe. The Man-in-Simulant Test (MIST) used in NFPA 1994 provides a

dynamic, human subject assessment for whether a surrogate chemical

will leak through ensemble closures and interfaces into the suit. MIST

combined with a rigorous manikin-based liquid inward leakage test provides

a comprehensive evaluation of protective ensembles to fully qualify the

ensembles for needed levels of overall integrity to prevent exposure to

hazardous materials.

Are totally encapsulating Level A suits being used more frequently

than the risk assessment or hazard might dictate?

Yes. The purpose of PPE in emergency response is to provide sufficient

protection from potential exposures identified in the initial risk assessment

at the emergency scene and allow first responders to safely carry out their

respective tasks or mission. All PPE causes restrictions in wearer functionality

that generally worsen as protective performance is increased. If protective

performance is set too high based on unrealistic levels of chemical exposure,

then the ensemble is generally over-designed for its intended use, which

results in decreased wearer functionality. Over-designed PPE creates hazards

just as under-designed PPE does and can lead to issues such as increased

likelihood of heat stress or entrapment of first responders.

Are there situations where a total encapsulating NFPA 1991 suit is

still needed for protection?

Yes. Totally encapsulating NFPA 1991 certified suits have utility in responses

involving direct contact with pressurized liquids and pressurized vapors,

particularly as may occur at chest level or higher, such as might occur in

the mitigation of broken chemical lines. However, there are many more

situations where a non-encapsulating suit certified to NFPA 1994 Class 1

offers appropriate protection. This is particularly true for missions not

involving direct contact with pressurized hazardous materials and where

there is the need for greater maneuverability and physical challenges present

in non-line of site rescue for chlorine or ammonia gas environments and

during urban search and rescue missions.

Is there substantial value for more form-fitting, greater functional

high-end protective ensembles?

Yes. Physical restrictions in movement, hand function, vision, hearing,

and loss of comfort all limit first responders during hazardous chemical

responses. In most cases, these limitations create more likely risks to first

responders than exposure to hazardous materials. In some types of missions,

first responders require a high level of functionality in order to carry out

specific tasks and missions. The balance of protective performance

with functionality and other human factors (e.g., thermal comfort) is a key

consideration in the selection of appropriate PPE for hazardous materials


Has research been performed on the effects of chemicals on the

SCBA and its components?

Yes. Intertek Testing Services, one of the independent organizations that

evaluates and certifies SCBA systems against the NFPA standards, has

performed extensive evaluations of the SCBA and its components in

chemical environments at high gas/vapor exposure or liquid splash levels.

This work, funded by the Department of Defense, has demonstrated that

SCBAs and their components maintain their performance capabilities

during and after chemical exposure with negligible chemical in the breathing

zone. It is also important to note that decontamination of the SCBA should

be done as soon as possible to minimize any effects of chemicals on

exposed SCBA components.

Are hazardous materials protective ensemble tests set at appropriate

levels to define the barrier performance of ensemble materials?

Yes and No. It depends on the standard being applied. For NFPA 1994

protective ensembles, testing is carried out for the individual classes under

different conditions, which are matched appropriately with the protection

offered by an SCBA or other respiratory protective equipment. These classes

are based on the high end of realistic exposure concentrations. Industry

often tests PPE clothing materials against chemicals at 100% concentration

for relatively long periods of time (8 hours). This results in garments with

outstanding barrier performance, but it often creates serious trade offs such

as material flexibility that affects mobility and other attributes important for

the operational and functional effectiveness of the wearer.

Is it possible to use test data based on a limited number of chemicals

to qualify the barrier performance of ensemble materials?

Yes. It is impossible to have permeation test data on every possible

chemical. Moreover, chemical exposures may involve other factors,

including their concentrations, exposure times, temperature, and

combinations in mixtures. For this reason, groups of selected chemicals

are used as part of NFPA standards, which generally use smaller molecule

chemicals (which permeate faster and are a greater exposure hazard) to

represent entire classes of chemicals and thus broaden the use of data. In

addition, NFPA standards apply these groups of chemicals to qualify not

only the base garment or suit material, but also the gloves, footwear,

seams, and other components of the ensemble. Reliance on garment/suit

material test data only is considered a dangerous practice in the selection

of protective ensembles.

Can issues of field testability and confidence in gross decontamination

affect perceptions of protection?

Yes and No. Detailed inspections are needed to assure that PPE remains

viable for its intended use, but field testing may not provide a “full” picture of

protective capabilities. It is essential that information be offered that shows

contaminants can be removed, but there are often circumstances in which

chemical exposure occur where disposal of the ensemble will be the result

of a post-incident review. What is important is the ability to perform gross

decontamination to allow the safe doffing of ensembles without contaminant

transfer to first responders or those assisting them.

Are there other forms of evidence that are important for demonstrating

the use of non-encapsulating ensembles for high end protection?

Yes. NFPA 1994 sets a framework of minimum design, protective

performance and labeling requirements for certified ensembles used

both in hazardous materials emergency and CBRN terrorism incidents.

Additional demonstrations of ensemble performance are necessary to

show how the ensemble can protect against accidental flash fires or other

short-duration high heat/flame sources; ease of decontaminating

ensembles and limiting contaminant transfer during doffing.