3.4 SCBA Emergency Procedures & Fit Testing

3.4 SCBA Emergency Procedures & Fit Testing

RIC/UAC Transfill Operations

During a firefighter rescue operation, a Rapid Intervention Crew (RIC) may encounter a downed firefighter who is trapped, injured, and low on air. Modern SCBAs certified under NFPA 1981 are equipped with a Rapid Intervention Crew/Company Universal Air Connection (RIC/UAC). The RIC/UAC is a male, high-pressure quick-connect fitting located on the SCBA regulator block, typically near the cylinder valve assembly.

The RIC/UAC is designed for one specific function: to quickly transfill air from a high-pressure rescue cylinder (part of a RIC bag) into the downed firefighter's SCBA cylinder.

Transfill Procedure and Mechanics

When a RIC team connects the female coupling of a rescue cylinder hose to the downed firefighter's UAC fitting, air pressure equalizes instantly between the two cylinders. This process takes only a few seconds and occurs without requiring the firefighter to remove their facepiece, disconnect their regulator, or interrupt their air supply. The transfill is driven purely by pressure differential; air flows from the higher-pressure rescue bottle to the lower-pressure SCBA cylinder until they are equalized.

[!CAUTION] Safety Restrictions on Transfilling

• The RIC/UAC must never be used for routine air sharing or buddy breathing between two active, working firefighters. It is strictly an emergency rescue connection.
• Connecting two working SCBAs together via their UACs will cause the pressure to equalize between them, instantly depleting the air supply of the donor firefighter and endangering both lives.
• Traditional "buddy breathing" techniques (sharing a single regulator or facepiece) are obsolete and prohibited under NFPA standards due to the extreme risk of inhaling toxic gases during regulator exchanges.

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The Bypass/Purge Valve: Function and Troubleshooting

The second-stage regulator is equipped with a red manual override knob known as the bypass valve or purge valve. Under normal operation, the regulator operates on demand, opening only when the firefighter inhales. However, if the regulator's internal demand valve, main diaphragm, or electronics fail closed, the regulator will stop delivering air.

Key Functions of the Bypass Valve

• Emergency Air Flow: If the regulator fails shut, the firefighter can open the bypass valve by turning it counterclockwise. This bypasses the demand diaphragm and delivers a continuous, unregulated flow of breathing air directly into the facepiece, allowing the firefighter to breathe and exit the IDLH atmosphere.
• Clearing Condensation: If extreme humidity or cold temperatures cause the interior of the facepiece lens to fog or accumulate condensation, a brief blast from the bypass valve will clear the moisture.
• Clearing Contaminants: If a momentary gap in the facepiece seal occurs (such as during a fall or impact), opening the bypass valve creates high positive pressure that purges any contaminated ambient air out of the mask.
• System Depressurization: During post-use inspection and shutdown, the bypass valve is opened to bleed off residual pressure trapped in the hoses after the cylinder valve is closed.

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Profile Reduction & Entanglement Techniques

Firefighters operating in structural collapses or search operations may become trapped by collapsed studs, ceiling wires, or narrow rafters. If a firefighter must pass through an opening that is narrower than the width of their SCBA pack, they must perform a profile reduction technique.

The Swimming Method

The most common profile reduction technique is the swimming method. The firefighter maintains their facepiece seal and positive pressure. They unbuckle the SCBA waist strap and loosen the shoulder straps. The firefighter then slips their left arm out of the left shoulder strap first. The right shoulder strap must remain in place because the low-pressure regulator hose typically travels over the right shoulder. Slipping the right shoulder strap off first runs the risk of pulling the hose taut, tearing it, or disconnecting the regulator. With the left arm free, the firefighter swings the SCBA pack off their back and holds it in front or to the side (resembling a swimming stroke) to reduce their profile and crawl through the restricted space. Physical contact with the SCBA harness must never be lost.

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Respiratory Fit Testing (OSHA 1910.134)

To ensure that an SCBA facepiece provides a reliable, airtight barrier against IDLH atmospheres, firefighters must undergo formal fit testing. Fit testing is federally mandated by OSHA Regulation 1910.134 (the Respiratory Protection Standard).

Fit Testing Frequencies

OSHA requires that a fit test be conducted:

1. Annually: At least once every 12 months.
2. Whenever Gear Changes: If a firefighter is issued a different size, brand, or model of facepiece.
3. Physical Changes: If the firefighter experiences significant physical changes that could alter their facial structure, such as major dental work, facial surgery, scarring, or a weight change of 10% or more.

Types of Fit Testing

• Qualitative Fit Testing (QLFT): A pass/fail test that relies on the wearer's sensory detection (taste or smell). The firefighter wears the facepiece (fitted with particulate filters) under a hood while a testing agent—such as Bitrex (bitter), saccharin (sweet), or irritant smoke—is aerosolized. If the firefighter can taste or smell the agent, the seal has failed.
• Quantitative Fit Testing (QNFT): A numeric test that measures the actual leakage of particles into the facepiece. A specialized instrument (such as a PortaCount) is connected to a probed facepiece. It counts the number of microscopic ambient particles outside the mask versus the number inside. This ratio generates a Fit Factor. For positive-pressure SCBA facepieces, OSHA requires a minimum fit factor score of 500.

Facial Hair Restrictions

OSHA 1910.134 strictly prohibits any facial hair—including beards, goatees, or long sideburns—that lies along the sealing surface of the SCBA facepiece. Even a minor amount of stubble or growth will break the face-to-silicone seal. While the positive-pressure regulator may temporarily compensate by pushing air out of the leak, this drastically increases air consumption, leading to premature cylinder depletion and risking toxic gas penetration under sudden negative pressure spikes.