Breakthrough Times and Permeation
Information on breakthrough times and permeation is included in this standard in recognition that
supplied-air suits are often used for protection against radiological gases and vapors, primarily
tritium, as well as non-radiological gases and vapors. This information is not intended to require
breakthrough and permeation testing for every chemical that a supplied-air suit may be exposed.
Likewise, a specific assessment is not required for every chemical for which breakthrough and
permeation data is not available. Testing or assessments should only be done when a credible
exposure scenario and health concern exists. Information on this topic can be found in Guidelines
for the Selection of Chemical Protective Clothing published by the American Conference of
Governmental Industrial Hygienists (ACGIH) and Chemical Protective Clothing published by the
American Industrial Hygiene Association (AIHA).
When evaluating the results of breakthrough and permeation data, the conditions under which the
supplied-air suit is used should be taken into consideration. For example, a polymer with a short
breakthrough time (several minutes) and significant permeation rate to a chemical would not likely
be suitable for immersion in that chemical. However, this polymer might be adequate for protection
from splashes of the same chemical if user instructions addressed adequately the scenario. A
supplied-air suit should be considered to provide adequate resistance to permeation and
breakthrough if workers do not receive a radiation dose or chemical exposure that exceeds
established criteria intended to minimize potential health effects.
Where available, resistance to permeation and breakthrough can be evaluated using information
available in reference texts or from manufacturers. While reference texts often provide sufficient
information to make informed decisions, evaluators should be more cautious when using
manufacturer's literature. Often, a manufacturer's literature is limited to general statements such as
a particular polymer's resistance to permeation and breakthrough is excellent, very good, good, etc.
While useful, one manufacturer's information may not be applicable to another manufacturer's
polymer. Contacting the manufacturer can often yield more details, i.e., test method and test results,
to provide additional confidence in the data.
Where exposure to the chemicals are not considered serious, i.e., the volume of chemicals involved
is small and they are of low toxicity, a review of manufacturers information, recognized references,
and qualitative estimates from immersion testing may be all that is necessary, in particular if
operational experience supports this decision.
When reference texts or manufacturer's data do not provide sufficient information to evaluate a
planned use for a supplied-air suit, it may be possible to develop qualitative estimates of a
polymer's resistance to permeation and breakthrough by immersing a sample of the polymer in the
chemical in question. Following immersion, an examination for visible degradation, swelling, or
weight change can provide sufficient information. Quantitative testing as described in American
Society for Testing Materials (ASTM) Method F739-85 can be performed if necessary.