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What Are the 4 Main SCBA Components?

There are four main parts that make up a self-contained breathing apparatus (SCBA). Each part is crucial in keeping the wearer safe in hazardous breathing environments. The four main components are as follows:

  1. One or two cylinders containing compressed air.
  2. A harness to mount the cylinders on the back of the person.
  3. A respiratory system, normally made up of air hoses and regulators.
  4. A facemask that is attached to a demand valve.

Throughout the following article, we will be diving into details about each of the four main components. We will also be discussing why knowing the various parts is important to employee safety.

Why Is Knowing the Main Components Important?

Knowing what makes up the different parts of your SCBA gives you an advantage when it comes to pre-shift inspections. This allows you to ensure that your SCBA will protect you the way it should before entering into an environment filled with toxic air. Take this case study for example:

Case Study:

Hannah was removing a regulator from a chlorine gas cylinder to perform yearly maintenance and repacking. When she attempted to close the shutoff valve, the valve malfunctioned and stopped turning. Unfortunately, she didn’t double check her work and did not realize the valve was still slightly open. When she removed the regulator, chlorine gas escaped. As soon as Hannah realized this, she quickly removed herself from the area.

Understanding the danger of the situation, she grabbed an SCBA, put it on without checking the seals or valves, and rushed back in. As she attempted to fully close the shut-off valve, she was overwhelmed by the gas. Again, she removed herself from the area, caught her breath, and rushed back in — this time, successfully closing the valve. She collapsed as she was removing her SCBA, and a coworker rushed her to the hospital. She suffered from toxic exposure and chemical burns to her lungs and respiratory system.

Had Hannah known what to look for when she was putting on the SCBA, she would have realized that the seals were worn and the valves were open. Because she did not properly inspect it beforehand, she suffered from major chemical burns and permanently injured her lungs.

Respiratory health needs to be taken seriously on every job. Tackling the most dangerous respiratory hazards requires the most thorough protective equipment.

SCBA Air Cylinders

Air cylinders are the most prominent component of a SCBA. The air cylinder of the open-circuit SCBA is referred to as the rebreather since it recycles the air. In closed-circuits, however, air cylinders are filled with oxygen in a compressed form, allowing a rescue worker to enter areas that are filled with smoke and fire and effectively rescue trapped or unconscious persons.

The air cylinders in the breathing apparatus must be routinely inspected, and they must be replaced or recharged after any rescue operation is over in order to prevent them from being empty the next time a rescue operation is necessary.

Different Types of Cylinders

Air cylinders can be categorized into three different classes, depending on the type of SCBA that is being used. There is a time limit and pressure limit for each type of cylinder. These three classes of cylinders are:

What Are Cylinders Made Out Of?

Originally, SCBA cylinders were made out of steel. But, the cylinders were on the heavier side and made it difficult for employees to wear them for a certain period of time. So eventually, aluminum became the material of choice for cylinders.

Manufacturers began to combine synthetic materials with the aluminum to reduce the weight even further. Cylinders made out of this synthetic material are called composite cylinders.

The Frame & Harness

The frame and harness enable you to comfortably carry the air cylinder on your back while keeping it out of the way of your job.

The harness assembly consists of two adjustable shoulder straps and an adjustable waist strap with a quick release buckle. Keep a look out for any loose fasteners or broken welds, and check the frame for cracks or bending.

The Breathing Apparatus Respiratory System

The SCBA’s respiratory system has the means to reduce the pressure of air from the cylinder and of supplying the wearer with air on demand. The respiratory system is made up of different parts, each one playing a vital role in delivering breathable air to the wearer of the SCBA.

Air Hoses

Your SCBA’s air hoses need to be checked for cuts, kinks, and evidence of heat or chemical damage (like splits or bubbling). Check for cracked or worn-out connectors in the fittings on the ends of the hoses. Make sure the hoses attach to the rest of the equipment securely and conveniently.


The regulator controls the flow of air from the air cylinder to the facepiece, ensuring the user always gets the proper amount of breathable air.

It is important that you look for external damage on the regulator, such as cracks or loose contacts. In particular, if there’s a risk that several employees might use the same piece of equipment, make sure the regulator is spotless and debris-free. This would ensure that each employee will be given a fair chance to properly inspect the piece of equipment before using it.

The Facepiece

The facepiece aids in generating a gap of breathable air around your lips and nose. Additionally, it can protect you from flying objects and other airborne dangers.

When performing an inspection, make sure the visor is clean and free of scratches, cracks, and warping. Examine the fabric around the visor for rips, holes, tears, and an abnormal amount of flexibility or stiffness.

What Is an SCBA?

As stated earlier, the acronym SCBA stands for self-contained breathing apparatus. An SCBA is a respiratory device that contains and delivers breathable, compressed air. It is generally used by firefighters and rescue workers working in an environment that has:

Open vs. Closed Circuit SCBA Systems?

In an open-circuit system, the air from the air cylinder is pumped directly into the user’s breathing mask. Any exhaled air is expelled directly from the system.

A closed-circuit system (also called a rebreather) works by recycling the user’s exhaled air into breathable air. The exhaled air passes through a special filter in the system that removes any excess carbon dioxide. Then, new oxygen is added from a compressed oxygen reserve, and the air is pumped back into the breathing mask to start the cycle over.

Standards for SCBA

Employers are required by OSHA to provide their employees with a respirator that is suitable for the tasks they will be completing. Employers are also required to establish and maintain a respiratory protection program within their workplace and make it available to all working employees.

When it comes to the manufacturing of SCBAs, The National Institute for Occupational Safety and Health (NIOSH) is the primary regulatory and certification agency. According to them, the manufacturer is responsible for establishing the SCBA’s service life, identifying cautions and limitations for use, and providing instructions for use and maintenance procedures for SCBAs.

Respiratory Protection Program

All required operating procedures for working with SCBAs must be laid out in your employer’s respiratory protection program.

The purpose of this program is to ensure that all employees who are required to wear respiratory protection are protected from respiratory hazards through the proper use of respirators. A respiratory protection program is required to include procedures and schedules for SCBA:

Make sure to read and understand your employer’s respiratory protection program. Employers must continually update the program to incorporate any new workplace dangers and safety concerns. Any adjustments your employer makes to the program over time should be noted.

Immediately Dangerous to Life or Health

Immediately dangerous to life or health (IDLH) is a term used to describe any environment where the atmosphere contains any amount of toxic, corrosive, or asphyxiant substance, posing an immediate risk to an employee’s life.

It can also refer to environments that could potentially cause irreversible or delayed adverse effects on someone’s health or would impair a person’s ability to escape from the dangerous environment.

Appropriately wearing and using an SCBA when working in an environment like this can mean the difference between life and death.

A Little About Our Trainings

Our team here at Hard Hat Training have successfully developed more than 200 safety training courses. Our courses range from topics such as pole-top rescue all the way to personal protective equipment. All of our courses were designed to comply with safety standards as well as to keep the students’ minds engaged.

It’s As Easy as One, Two, Three

No one should ever use a SCBA without the appropriate training since they are complex pieces of safety equipment. Training for SCBAs must be specific to the precise brand and type of apparatus. Employees must learn how to properly put on, take off, inspect, maintain, and use their equipment.

This is why our SCBA Training (Self-Contained Breathing Apparatus Safety Course) was developed to be efficient, OSHA Aligned, as well as affordable.