One of the greatest innovations in the fire service is the Self-Contained Breathing Apparatus (SCBA), which is a critical component in the personal protective equipment (PPE) used by today’s firefighters. This equipment is essential for allowing firefighters to operate in hostile fire environments.
In a human body, the respiratory system is both the biggest system and the easiest to compromise. One toxic breath can make the difference between life and death.
Firefighters cannot always see the contaminants that are present within a hostile environment. This is why firefighters must always wear an SCBA whenever they are in any kind of environment immediately dangerous to life and health.
Out of everything that firefighters wear, SCBA provides the highest level of protection.
Firefighters are able to gain deeper access into burning structures to perform rescue functions, locate and suppress the fire and prevent further property damage.
Three Main SCBA Components
An SCBA typically has three main components all connected together and mounted to a carrying frame.
- high-pressure tank
- pressure regulator, and
- inhalation connection (mouthpiece, mouth mask or face mask),
A self-contained breathing apparatus may fall into one of two categories: close-circuit or open-circuit
The closed-circuit SCBA, also known as a rebreather, operates by filtering, supplementing, and recirculating exhaled air.
Closed-circuit SCBAs are used when a longer-duration supply of breathing gas is needed or when responders require a system which is smaller than the open-circuit SCBA, which has a large air cylinder. Closed-circuit SCBAs also weigh less than open-circuit SCBAs because they use a smaller cylinder that contains pure oxygen. The full-facepiece mask of a closed-circuit SCBA holds in the breathing air and is designed to provide some protection from the operational environment.
Before open-circuit SCBA’s were developed, most industrial breathing sets were rebreathers.
Open-circuit industrial breathing tanks are 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).
An open-circuit rescue or firefighter SCBA has a full-face mask, regulator, air cylinder, cylinder pressure gauge, remote pressure gauge (sometimes with an integrated Personal Alert Safety System device), and a harness with adjustable shoulder straps and waist belt which lets it be worn on the back. The air cylinder usually comes in one of three standard sizes: 4 liter, 6 liter, or 6.8 liter. The relative fitness, and especially the level of exertion of the wearer, often results in variations of the actual usable time that the SCBA can provide air, often reducing the working time by 25% to 50%.
SCBA Air Cylinders
Air cylinders are made of aluminum, steel, or composite construction (usually carbon-fiber wrapped). The composite cylinders are the lightest in weight and are therefore preferred by fire departments, but they also have the shortest lifespan and must be taken out of service after 15 years. Air cylinders must be specially tested every 5 years. During extended operations, empty air cylinders can be quickly replaced with fresh ones and then refilled from larger tanks in a storage system or from an air compressor brought to the scene.
Every fire department within the North American continent has access to an adequate amount of SCBAs, which means part of firefighter training will include how to properly use SCBA.
A third-party organization conducts SCBA testing to ensure their performance meets or exceeds industry standards.
SCBAs are expensive to purchase and maintain, but they are relatively cheap to use. The only commodity used when in full operation is breathing air and refilling the tanks with regular breathing air is very inexpensive.
The units also have personal safety alarms and heads-up displays that require batteries to operate — often AA batteries. These, too, are inexpensive.
SCBA Buddy Breathing
There are times when a firefighter’s air tank may malfunction, run out of air, or sustain damage from falling debris. At times like these, it is important that firefighters were trained to help each other out. Buddy Breathing is a technique employed in a situation where one firefighter helps another who has no access to air. Firefighters learn how to share the air in one firefighter’s air tank while they exit the fire scene.