SCBA Flashcards
What does IDLH stand for?
Immediate danger to life and health
What does SCBA stand for?
Self-contained breathing apparatus
What is an SCBA?
A device that provides breathable air in a hazardous or toxic atmosphere. Self-contained means it is not dependent on a remote supply.
What are the three main components of an SCBA?
- High pressure tank
- Pressure regulator
- Inhalation connection (mouthpiece, face mask)
Explain the two main categories of breathing apparatus.
Open circuit: filled with filtered, compressed air, rather than pure oxygen. Typical open-circuit systems have two regulators; a first stage to reduce the pressure of air to allow it to be carried to the mask, and a second stage regulator to reduce it even further to a level just above standard atmospheric pressure. This air is then fed to the mask via either a demand valve (activating only on inhalation) or a continuous positive pressure valve (providing constant airflow to the mask).
Closed circuit: filters, supplements, and recirculates exhaled air. Used when a longer duration air supply is needed, such as for mine rescues. More compact than open circuit. Also called a rebreather. Used by frogmen for covert operations because it doesn’t give off tell-tale bubbles.
What is a PASS, or DSU?
Personal Alert Safety System
Distress Signal Unit
It is a small, battery powered, piercing electronic bleeper that is activated either manually or after a certain short period without detecting movement. The loud audible alert notifies others that the wearer is in distress or has stopped moving, subsequently triggering an immediate response to rescue the firefighter in distress.
How does temperature affect the pressure gauge readings?
As ambient temperature decreases, so does the pressure inside the cylinder. A temperature drop of 5.5°C (about 10°C) causes a pressure change of about 82psi.
Failure to accurately account for the drop in pressure could lead to under filled cylinders, which could in turn lead to a firefighter running out of air prematurely.
