Self-contained breathing apparatus

AIR ON THE SIDE OF CAUTION

By Michael Robbins

"Any time you wear a respirator," says Ron Meyers, "you must have a program. If you don’t have a program, you’re not meeting the CSA standard."

Think of self-contained breathing apparatus, or SCBA as it’s generally known, as a parachute. The only time you use it is when you really need it, and when you need it at all, you need it so much that your life depends on it.

SCBA is the highest and most secure level of breathing protection, and it is used as the first and often only line of defence against atmospheres that are immediately dangerous to life and health (IDLH).

Every SCBA system consists of the same basic elements: a tank of compressed breathing air that the user wears in a backpack or strapped to a waist belt; a breathing tube which leads to a full face mask; and a regulator that delivers breathable air to the mask at close to atmospheric pressure.

Who needs SCBA? "The biggest area by far for SCBA is firefighters," says Michelle Breen, a technical safety specialist with Dalloz Safety in Reading, Pennsylvania. "But there are a lot of people out there who cross the line between cartridge respirators and supplied air." There are, she says, essentially five classes of people who need to use SCBA:

* firefighters, who must enter smoke and contaminant filled buildings to fight fires and rescue occupants;

* emergency response or rescue teams, who are called upon to enter spaces with known or unknown contaminants to rescue occupants;

* hazardous materials emergency response teams, who respond to spills and leaks of toxic or unknown substances;

* people who work in confined spaces in which the atmosphere cannot be made safe through such techniques as ventilation; and

* people who work in certain industrial settings (such as some kinds of spray painting) where the atmosphere cannot be made safe through other measures.

SCBA is only one of several types of breathing protection, or "respirators", that are used to provide protection against a variety of hazardous substances that may be in the ambient air of a workplace. Hazards that may require breathing protection include the following:

* dust or other "nuisance particulates";

* hazardous particulates such as asbestos fibres;

* toxic gases and vapours;

* hazardous mists, or tiny floating droplets of liquids;

* fumes, or particles of metal that have condensed in the air after being vapourized, usually by welding;

* and, in a class by itself, atmospheres with insufficient oxygen.

To provide breathing protection in these hazardous atmospheres, there is a variety of devices available (see "The Air We Breathe", January/February 1998, pp. 44-49). These include the following:

* dust masks that filter out nuisance contaminants, but are not considered true respirators;

* dust, fume and mist respirators that filter out contaminants (see "A Fitting Selection", March 1998, pp. 66-71);

* powered air filtering respirators that use a pump to force air from the workplace through a filter to provide breathable air to the wearer;

* chemical cartridge respirators that remove specific gases and vapours from the air;

* air-line respirators that provide clean air from outside the workplace and deliver it to a face mask, either from a tank or from a compressor with an outside intake; and

* self-contained breathing apparatus that consists of a tank of breathing air carried by the wearer and connected to a face mask.

The last two on the list, SCBA and air-line respirators, both deliver clean breathing air to the user’s face mask, and represent the highest level of breathing protection. They provide safe, clean air that does not come from the workplace (as opposed to the other types of respirators, all of which filter or chemically clean the contaminated workplace air).

However, "supplied air" systems, as SCBA and air-line systems are collectively called, are clearly also the most complex, involved, difficult and expensive way of providing safe air to breathe. They are used only when there is no easier way to ensure the safety of the worker.

Air-line respirators, in which the wearer is connected to the air supply by a long hose, impose restrictions in mobility that make it impractical in many confined spaces, and certainly for any firefighting or rescue application. "Generally," says Breen, "if a worker has to work more than 300 feet from the air source, the air-line system is ruled out. The air-line system is mainly used in industrial applications where a great degree of mobility is not required." It is also used, she adds, when longer duration is required, since a compressor-fed air-line system can run indefinitely, while SCBA tanks have only a 30 or 60 minute air supply at most.

SCBA is used when a fully portable system is required, and when mobility and range of travel are important.

Supplied air systems, including SCBA, must be used if any of the following conditions apply:

* when there is, or may be, an oxygen deficiency and the ambient air cannot provide enough oxygen to sustain life;

* when there is, or may be, a toxic substance in the air that cannot be removed by an air-purifying respirator (such as if there is no chemical cartridge for the substance);

* when a toxic substance exists, or may exist, at too high a level (beyond the "safety factor" listed in the CSA standard) and an air-purifying respirator cannot be used as a result;

* when the substance in the atmosphere has poor warning characteristics, meaning that an air-purifying respirator cannot be used because the wearer would not be able to detect leakage;

* when there is, or may be, an unknown toxic substance in the atmosphere; or

* when a known toxic material exists, or may exist, at an unknown level.

These are the central facts that define the use of self-contained breathing apparatus, and it leads to a number of logical conclusions that, in turn, define the way SCBA is used in the workplace.

Conclusion number one: If you need SCBA in the workplace, you can’t just buy it off the shelf and use it. You have to make a major commitment to an SCBA program. "Any time you wear a respirator," says Ron Meyers, a project manager for standard development in the oh&s program of CSA International, "you must have a program. You have to go the whole nine yards. If you don’t have a program, you’re not meeting the CSA standard."

Conclusion number two: If you are not already trained and competent in the area of SCBA, and if there is no such person available in your workplace, you will need to send someone for training. If you have to use SCBA, all the users will need training in its use, and at least one person will require much more extensive training in how to set up, administer and audit the program.

Conclusion number three: Given the above two conclusions, you should do everything humanly possible to eliminate the need for SCBA in your workplace. "You should always try to eliminate the hazard, through elimination or substitution of the hazardous material, or through ventilation or other means," says Meyers.

The standards

In Canada, the use of self-contained breathing apparatus is effectively governed by the CSA International standard CSA Z94.4-93, Selection, Use and Care of Respirators. The word "governed" needs some explanation, however.

Strictly speaking, says Meyers, compliance with the CSA standard is voluntary. The CSA does not have the power to require employers or workplaces to follow its standard. However, following the selection, use and care guidelines in the standard does, effectively, have the force of law in Canada.

When the standard is referenced in legislation (as it is in many provinces) its provisions are effectively carried into law. And, perhaps equally important, the concept of due diligence requires employers to do everything reasonably possible in the circumstances for the protection of a worker. Since the CSA standard is the widely accepted definition of what is reasonable, any employer attempting to set a lower standard would not be duly diligent.

The standard, as the name suggests, deals with all areas of the selection, use and care of respirators (and not just SCBA). It deals with program administration, hazard identification, fit testing, training, the use and maintenance of equipment, health surveillance of users and program evaluation. It is, in fact, a blueprint for respirator use in the workplace.

The standard does not deal with the manufacture of equipment. "CSA does not test respirators," says Ron Meyers. "If equipment is NIOSH approved," he says, referring to the National Institute for Occupational Safety and Health in the U.S., "we accept that. Any respirator approved by NIOSH is acceptable, but there are other acceptable standards from Europe or Japan. We don’t favour one over the other," he adds, "but we do have a close relationship with NIOSH."

Another certification or approval that appears on many SCBA systems is "ANSI/NFPA 1981 Standard". ANSI is the American National Standards Institute, a standard setting body not unlike CSA International, although it does not test products. The NFPA is the National Fire Protection Association, and the standard they set for SCBA actually exceeds the NIOSH requirements. Bruce Schorer, an expatriate Canadian who is now director of international sales for Scott Health and Safety in Charlotte, North Carolina, says buyers of SCBA equipment should look for the NFPA rating.

"The NIOSH standard has fallen behind the NFPA in recent years," says Schorer. "The NFPA has environmental and flame tests that may not be appropriate in industrial applications, but that are important to firefighters. But the performance requirements as they relate to air supply are also different. NIOSH requires a system to provide 40 litres of air per minute, and that may be inadequate under the extreme loads we see in rescue work and firefighting. NFPA calls for 100 litres per minute." Many NFPA rated systems, he adds, can actually supply up to 300 litres of air per minute.

pull quote "NIOSH requires a system to provide 40 litres of air per minute, and that may be inadequate under the extreme loads we see in rescue work and firefighting. NFPA calls for 100 litres per minute," says Bruce Schorer.

"It’s not just physical exertion" that may lead to higher demands for air, says Schorer, "in addition, in hazardous materials situations, there is often a degree of anxiety because of the hazardous situation you are responding to."

Kerin Sparks, of MSA Canada in Toronto, agrees. "You have to look at the minimum work rates and the maximum work rates, and that affects the length of time an SCBA will last. A normal 2216 pound-per-square-inch (psi) cylinder may be rated for 30 minutes, but the standard duration is actually from 15 to 20 minutes."

The same applies to 4,500 psi tanks rated for an hour, says Sparks. "It may only last half or three-quarters as long as the rated time," he says. The 60-minute cylinders used in hazardous materials response tend not to be used up as fast, he adds, because "in a chemical spill situation, you’re not running around and doing actual work at a high rate."

Both NIOSH and CSA are currently working to revise and update their standards.

In addition to the standard for the selection, use and care of respirators, systems should also comply with the requirements of CSA-B339-88, Cylinders, Spheres and Tubes for the Transportation of Dangerous Goods (with regard to the pressure vessel, or tank); and CSA Z180.1-M85, Compressed Breathing Air Systems.

The program

A respiratory protection program, if it is to protect workers at all, has to be as airtight as the face seal on the user’s mask. A program that complies with the CSA standard, and thus with the law and accepted standards of due diligence, consists of a number of elements:

* a program administrator who has overall responsibility for ensuring that the program is in compliance;

* the identification and assessment of respiratory hazards in the workplace;

* the selection of appropriate respirators (which may or may not include SCBA);

* a program of fit testing for all users;

* training for all users in the proper use and maintenance of the equipment;

* proper use of respirators;

* cleaning, maintenance and storage of respirators;

* health surveillance of respirator users; and

* evaluation of the overall program.

Such a program, clearly, is no simple matter to set up and maintain. Each element of the required program listed above would provide more than enough material for an article -- maybe even a book -- of its own. Perhaps it would be wise to revisit the sage advice of the CSA’s project manager, Ron Meyers: "Your best option is to eliminate the need for respirators." But for those workplaces that can’t, there’s just no two ways about it. If breathing protection is required, you just have to get with the program.

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BUYING TIPS FOR SCBA

* Added features to consider in an SCBA system include communications devices that make it possible to speak with co-workers while wearing a face mask.

* In addition to the 30- or 60-minute SCBAs, says Michelle Breen of Dalloz, "there are five-minute ‘escape’ systems. Any time you’re using an air-line respirator in a confined space, you need that five-minute backup system in case anything goes wrong." Escape, or "egress" systems are available with full or half face masks, or with hoods that cover the entire head and face. They are designed to give the wearer enough time to leave a danger area. (Ten and 15 minute models are also available.)

* Some systems have an "accessory hose" attachment that allows another person with SCBA to share the air in his or her tank. If one worker’s tank runs out, another worker can rescue him or her.

* Certain applications, such as underground mine rescue, use a different system of SCBA called a "closed circuit" system. These systems recirculate exhaled air, filter out the carbon dioxide and add just enough oxygen to bring the level up to that found in normal air. These systems are more complex, says Kerin Sparks, "But that’s pretty much what you need to have in mine rescue situations." The system can provide up to four hours of breathing air in a wearable system. "And," he adds, in a waiting-for-rescue situation "if you slow your breathing, calm yourself and sit down, you can get a lot more than that out of it."

* Ask the supplier about the life-cycle cost, advises Bruce Schorer. The testing requirements for the equipment, he says, make it important to consider the cost of the system over its lifetime. "The life-cycle cost may be highly important to a fire department or any heavy user that is using them daily. It may be less important for an industrial application that basically has them because they’ve been told they have to have them."

* Look for modular equipment, suggests Schorer. "Make sure the system is designed so that you can attach a whip for a supplied-air line," he says. "And make sure the system is compatible with encapsulating suits, and that there is provision for a pass-through device," he adds. "Another thing that’s important is to get a face piece that is compatible with air-purifying respirators. That way, you can assign one face piece to each person, whether it’s used with an air purifying system or an SCBA."

* Firefighters’ SCBA equipment, says Sparks, should be chosen for light weight. "Heat stress is the number one hazard faced by firefighters," he says. "Anything that can reduce the weight is going to be beneficial. There are carbon fibre cylinders that are a lot lighter, and some that have a lower profile," he says.

* SCBA for industrial use, however, should be built around comfort for the wearer. "Workers in industry tend to have these things on their backs for longer periods of time," says Sparks.

* Look for both consulting and training from the manufacturer or supplier. "Call the manufacturer and describe the requirements," says Sparks. "They should be able to come and look at the application and make sure that SCBA is the right thing." The supplier should also be able to provide training, he adds. "Education and training are the key," he says, "if you don't have those, you don’t really have anything."

* In the industrial and construction sectors, says Sparks, "It’s very important to make sure that subcontractors are also trained, that all the people coming onto the site have the training and the proper documentation. It’s one thing to make sure your employees meet the standards, but you can also be responsible for anyone else that comes onto your site."

Michael Robbins is a freelance writer specializing in health and safety. He is based in Toronto.

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