Escape breathing apparatus

This includes escape through water and in areas containing harmful gases or fumes or other atmospheres immediately dangerous to life or health (IDLH).

Contamination of the breathing gas may be avoided by relying on a good seal around the user respiratory interface, or by a small positive pressure relative to the surroundings.

Therefore selection relies mainly on the time required to escape, and the probability of IDLH or oxygen deficiency, rather than assigned protection factors.

An air purification type escape respirator includes a filter or absorbent cartridge suitable for the environment in which it is intended to be used.

They may use the pendulum type breathing system, which has larger dead space than a one-way loop architecture, but is simpler and cheaper to manufacture.

[3][6] A basic unit may use a bite-grip mouthpiece and nose clip, or may include goggles or a hood if eye protection is necessary.

[3][6] Potassium superoxide is violently reactive in contact with water, and could be dangerous for escape sets which may leak while immersed.

Submarine escape sets had a mouthpiece, so the user had to also wear a noseclip to prevent breathing water through the nose.

[citation needed] Open circuit escape breathing apparatus may be demand supplied or constant flow.

[3] A positive pressure open circuit breathing apparatus with a full-face mask provides the highest level of protection against a toxic environment, but is relatively complex, expensive, and requires greater competence to use efficiently.

Endurance depends on cylinder size and working pressure, effectiveness of the face seal, and level of exertion and anxiety of the user.

[3][6] Constant flow open circuit breathing apparatus delivers compressed air from a storage cylinder at about 40 litres per minute, regardless of the activity of the user.

[4] Some standards apply to the level of protection for the user, and others relate to the intrinsic safety of the equipment for use in flammable and potentially explosive atmospheres.

[9] Conformance with voluntary standards may be shown through third-party product certification such as those issued by the Safety Equipment Institute (SEI).