SCBA Information

Ranging in price from $3,000.00 to over $10,000, a pressure-demand SCBA (Self-Contained Breathing Apparatus) represents a substantial financial investment to employers. Before purchasing an SCBA, decisions must be made to ensure the SCBA selected is appropriate for its intended use. The type of application, the length of the application and the anticipated frequency of the application are all variables an employer must examine before purchasing an SCBA to make sure they're getting the correct product.


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Ranging in price from $3,000.00 to over $10,000, a pressure-demand SCBA (Self-Contained Breathing Apparatus) represents a substantial financial investment to employers. Before purchasing an SCBA, decisions must be made to ensure the SCBA selected is appropriate for its intended use. The type of application, the length of the application and the anticipated frequency of the application are all variables an employer must examine before purchasing an SCBA to make sure they're getting the correct product.
In the hierarchy of respiratory protection, SCBAs provide the highest level protection available. They offer respiratory protection against toxic gases and oxygen deficiency. The wearer is independent of the surrounding atmosphere because he or she is breathing with a system that is portable and admits no outside air.

 

Type of Application
When it comes to choosing an SCBA, the employer must first consider the intended application for the product. If the SCBA will be used for firefighting purposes, then a National Fire Protection Association (NFPA) 1981 compliant unit is necessary. If firefighting is not the application, then a basic National Institute for Occupational Safety and Health (NIOSH) compliant SCBA is most appropriate.

 

Industrial SCBAs
For applications other than firefighting, non-NFPA compliant SCBAs are a more economical alternative for employers. A NIOSH compliant industrial SCBA is appropriate for industrial confined space applications, applications where the levels of contaminants exceed the immediately dangerous to life or health (IDLH) concentrations, situations where the contaminant(s) and/or the contaminants concentration are unknown and oxygen deficient (oxygen concentrations below 19.5%) environments.

 

CBRN
The tragic events of 9/11 spurred NIOSH to establish testing and performance criteria for SCBAs intended for responding to CBRN agents. In January 2002, NIOSH began accepting approval applications from SCBA manufacturers who have developed SCBAs to meet the new NIOSH guidelines.

 


A CBRN agent approved SCBA must meet the following specifications:
NIOSH approval of the SCBA under 42 CFR Part 84, Subpart H
Compliance of the SCBA to NFPA 1981 for open-circuit self-contained breathing apparatus for firefighters
Approval of the SCBA to 42 CFR Part 84.63(c) special tests
Under 42 CFR Part 84.63(c) two special tests are defined. The two tests cover the following:
Chemical agent permeation and penetration resistance against distilled mustard and sarin
Laboratory respirator protection level (LRPL)

 


In the chemical agent permeation and penetration test, all components of the SCBA except the air cylinder must resist distilled mustard and sarin chemical agents. The SCBA is tested on an upper-torso manikin connected to a breathing machine operating at an air flow rate of 40 liters per minute.


The LRPL test is essentially a compilation of quantitative fit tests for 25–40 test subjects. The test subjects have a variety of facial sizes and shapes and represent a cross sample of the general population. To pass the LRPL test a SCBA must score a LRPL of 500 or greater on a minimum of 95% of the test subjects.

 

For more detailed information on the CBRN requirements visit the Centers for Disease Control and Preventions (CDC) NIOSH Web.
NFPA 1981 was updated again in 2013. The significant changes in this revision include the following 4 areas:
New performance and test requirements for Emergency Breathing Safety Systems (EBSS)
Addition of the Speech Transmission Index (STI) method for measuring speech intelligibility
New lens radiant heat resistance performance requirements and test method
New convection lens heat and flame resistance performance requirements and test method

Length of Application
Another important point to take into consideration when selecting an SCBA is the amount of time the SCBA-required task will take. NIOSH approved SCBAs are available with supply tanks capable of providing 15, 30, 45 or 60 minutes of breathing air. A NIOSH approved SCBA should not be confused with NIOSH approved egress or escape units. While both systems incorporate tanks of breathable air, egress units provide air for a shorter duration, typically either 5–10 minutes, and are intended strictly for escaping from a toxic or oxygen deficient environment. Unlike egress units, SCBAs are approved for entering toxic or oxygen deficient environments.

Unless an employer has a need for a 60 or 45-minute supply of breathing air, the 15 or 30-minute systems offer the advantages of cost and comfort. Because the air supply tanks are smaller on the 15 and 30-minute systems, they're generally less expensive and pack fewer pounds than 60-minute units. Even a couple of pounds can make a dramatic difference in comfort when it comes to strapping on an SCBA to complete a task

 

Frequency of the Application
Comfort also comes into play when considering how often the SCBA-required task occurs. If the SCBAs is only used in an emergency situation, such as shutting down a leaking valve or performing unexpected maintenance in a confined space, then comfort would not be as crucial as it would be in situations where the SCBAs is used on a regular basis. If an SCBA is used regularly, wearer comfort becomes a top priority. With SCBAs, greater comfort generally equates to less weight.
Two methods are used to reduce the weight of SCBAs. Both weight reduction techniques involve the SCBA cylinders. Manufacturers either reduce the weight of the cylinders by making them out of lighter materials or by packing more air into smaller cylinders; sometimes they combine both techniques.

 

Cylinder Materials
Originally SCBA cylinders were manufactured from steel. To reduce cylinder weight, aluminum became the material of choice for cylinders. Eventually manufacturers began to combine synthetic materials with aluminum to reduce the weight even further. These cylinders are generally referred to as composite cylinders. Within the composite category, there are hoop-wrapped and fully wrapped cylinders.

In more recent times, kevlar and carbon composite cylinders have been developed. Carbon cylinders are the latest and lightest in the evolution of SCBA cylinders. Unfortunately for the employer, as the weight of the cylinder decreases the cost of the SCBA generally increases. The lighter weight cylinders also have a shorter service life and require more frequent testing than their aluminum counterparts.

 

All SCBA cylinders require periodic testing. The frequency of the maintenance depends upon the cylinder material. For more information regarding hydrostatic testing and service life of SCBA cylinders see Quick Tips #307: SCBA Cylinder Hydrostatic Testing.

Many fire departments and some dive shops have the equipment and trained personnel to perform the hydrostatic testing on SCBA cylinders. The SCBA manufacturer, or the distributor it was purchased through, should be able to direct you to a test facility in your area.

 

High Pressure vs. Low Pressure
The other method of making SCBAs lighter is to pack a larger volume of air into a smaller cylinder. There are three pressure options available: high-pressure SCBA cylinders that can be pressurized to 4500 PSI, medium-pressure cylinders that can be pressurized to 3000 PSI and low-pressure cylinders that can be pressurized to 2216 PSI. Of the three classes, high-pressure and low-pressure are the most common options for SCBAs. Medium-pressure cylinders are most commonly used for scuba diving.
Both 60 and 45-minute SCBAs use high-pressure cylinders exclusively. The high-pressure is required in order to provide 60 or 45 minutes of breathing air in a tank that can be worn with relative comfort.