When the very air that we breathe is contaminated how can we protect ourselves and defend against its hazards?
The most important defence against respiratory hazards is to control the contamination at source and stop it entering the air in the first instance. This however, does not provide the solution to all circumstances and when it does not it will be necessary to use respiratory protective equipment.
Hazardous substances that can contaminate the air include dust, gases, fumes, mist, vapours, and smoke. Inhaling such contaminants can cause damage to many parts of the body including most commonly the nervous system, lungs, nose and throat. In some cases they can trigger allergic reactions such as asthma when inhaled. Oxygen-deficient atmospheres (i.e. when oxygen concentration in the air falls below 17%), also present an unacceptable hazard.
Occasionally work needs to be carried out in conditions that are described as being Immediately Dangerous to Life or Health (IDLH) and can occur when toxic chemicals, gases or particles are present or when there is a deficiency of oxygen. In such situations, individuals can be quickly overcome, are unable to effect an escape and could suffer severe and/or irreversible damage.
There are two ways to protect against such hazards. The first is to control the contamination at source and prevent it from entering the air in the first place. This can involve isolating the hazard, enclosing the function that is generating the contamination, ventilating the contaminated area and maintaining these systems to ensure they remain effective. In the situation that the source of contamination cannot be eliminated then the second method of protection is the use of respiratory protective equipment. Whilst this is often considered a last resort it is particularly practical when access to the contaminated area is needed for short periods of time or in emergency situations. Respiratory protective equipment suitable for these types of situations include masks, respirators, air-fed systems and self contained breathing apparatus.
Respiratory protection for fighting fires
As statistics show that three out of four fire fatalities are caused by smoke inhalation, it is essential that respiratory protective equipment is worn when firefighters are subjected to or enter a hostile environment were chemical fumes, dust, fire, deficiency of oxygen or other respiratory hazards are expected. In most instances these will be life threatening situations and the protection afforded to the rescue personnel attending must be the very best available.
The protection factors provided by different types of Respiratory Protective Equipment (RPE) are stated in BS EN 529:2005; Guide to implementing an effective respiratory device programme. As we face the increasing threat of terrorism, manufacturers and standards bodies are exploring ways to develop products capable of countering the types of hazards the modern firefighters and emergency response teams can expect to encounter, such as chemical, biological, radiological and nuclear agents.
The fire and rescue service will predominately utilise Respiratory Protective Equipment conforming to EN 137, self contained open circuit compressed air breathing apparatus. This consists of a single unit covering the eyes, nose and mouth area allowing the operative to communicate and move without compromising the level of protection. As with all protective equipment it is important that the compressed air cylinder aspect of the apparatus does not limit the firefighter in terms of weight or design and hinder them from operations. The apparatus must be capable of performing in all orientations.
|Appropriate current specifications include:|
|EN 140: 1999 Respiratory protective devices. Half masks and quarter masks. Requirements, testing, marking. Replaces BS 7356: 1990|
|EN 14387: 2004 Respiratory protective devices. Gas filters and combined filters. Requirements, testing, marking|
|EN 143: 2000 Respiratory protective devices. Particle filters. Requirements, testing, marking|
|EN 149: 2001 Respiratory protection devices. Filtering half masks to protect against particles. Requirements, testing, marking for filtering half masks for protection of the respiratory tract against particles|
|EN 12941: 1998 Respiratory protection devices. Powered filtering devices incorporating a helmet or hood. Requirements, testing, marking. Replaces BS EN 146: 1992|
|EN 12942: 1999 Respiratory protection devices. Power assisted filtering devices incorporating fullface masks, half masks or quarter masks. Requirements, testing, marking. Replaces BS EN 147: 1992|
|EN 14594: 2005 Respiratory protection devices. Light duty compressed air line breathing apparatus incorporating a helmet or hood. Requirements, testing, marking|
|EN 405: 2002 Respiratory protection devices. Valved filtering half masks to protect against gases or gases and particles. Requirements, testing, marking|
|EN 14594:2005 Respiratory protection devices. Compressed air line breathing apparatus incorporating a hood. Requirements, testing, marking. Replaces BS 4667: Part 3: 1974|
|EN 136: 1998 Respiratory protection devices. Full face masks. Requirements, testing, marking. Replaces BS 7355: 1990 and BS EN 136-10: 1992|
|EN 137:2006 Respiratory protection devices. Self contained open circuit compressed air breathing apparatus. Requirements, testing, marking. Replaces BS 7004: 1988|
|EN 138:1994(2000) Respiratory protection devices. Fresh air hose breathing apparatus for use with full face mask, half mask or mouthpiece assembly. Replaces BS 4667: Part 3: 1974|
|BS EN 14594:2005 Respiratory protection devices. Continuous flow compressed air line breathing apparatus Requirements, testing, marking. Replaces BS EN 139:1995, BS EN 270:1995, BS EN 271:1995, BS EN 1835:2000 and BS EN 12419:1999. Product Type Standard/Class Assigned (if applicable) Prot|