The Basic Rating Levels for Protective Suits:

Chemical or Hazmat protective clothing is classified in the US as Level A, B, C, or D, based upon the degree of protection they provide in hazardous environments.

Level A Chemical Suits

Level A suits are considered the highest level of protection against vapors, gases, mists, and particles, which consists of a fully encapsulating chemical entry suit with a full-face piece self-contained breathing apparatus (SCBA) or a supplied air respirator (SAR) with an escape cylinder. An individual wearing this level of suit must also wear boots with steel toes and shanks on the outside and specially selected chemical-resistant gloves for this level of protection. The breathing apparatus must be worn inside the suit to avoid any contamination with the outside environment. To qualify as Level A protection, a two-way radio is also worn inside the suit, often incorporating voice-operated microphones and an earpiece.

Level B Chemical Suits

Level B suits, like the Level A, also require an SCBA. Level B chemical protective clothing must provide protection against splashes from hazardous chemicals. In that the breathing apparatus is worn on the outside of the garment, Level B protection is not vapor-protective. It is worn when vapor-protective clothing, Level A, is not required. Wrists, ankles, face piece and hood, and waist are secured to prevent any entry of splashed liquid. Depending on the chemical being handled, specific types of gloves and boots are required. These may or may not be attached to the chemical suit. The chemical suit itself may be one piece or a two-piece hooded. To be fully compliant, Level B protection also requires the wearing of chemical-resistant boots with steel toes and shanks on the outside of the garment. As with Level A, chemical-resistant gloves and two-way radio communications are also required to meet this classification.

Level C Suits

Level C suits are almost identical to level B suits except for the required equipment needed for respiratory protection. With Level C suits, you have the ability to use other varieties of respiratory protection other than just SCBA. An individual should not use this level of protection unless the specific hazardous material is known and its concentration can be measured. Level C equipment does not offer the protection needed in an oxygen deficient atmosphere.

Level D Suits

Level D Suits do not provide protection from chemical exposure. A pair of coveralls or other work-type garment along with chemical-resistant footwear with steel toes and shanks are all that is required to qualify as Level D protection.