Heat and flame are not the only hazards that firefighters face during emergency response scenarios. This article looks at the silent danger that exposure to harmful gas poses to the modern firefighter and how to stay one step ahead.
No two jobs are ever the same. This is certainly the case for today’s firefighter who can be called out to attend anything from a roadside incident, a raging fire at an industrial unit or an underground confined space rescue. Each scenario has its own set of challenges and unpredictable elements which require a list of essential items to ensure safe operation. This was certainly the case when paramedics at the Green Bay Metro Fire Department in the U.S. responded to an emergency call at a local dentist’s office where a patient’s health was deteriorating. The standard issue Protégé ZM portable gas monitor attached to the officers’ bag sounded an alarm alerting them to the presence of carbon monoxide, resulting in an evacuation, potentially saving the lives of 20 people in the building. Incidents such as these demonstrate why the use of a personal gas monitor is becoming one of the most crucial items in a firefighter’s kit to ensure early warning of the presence of harmful hidden gases present in the atmosphere.
Gas monitor solutions have come a long way since the industry’s early, unsophisticated offerings that included the use of caged canaries taken down into the mines to forewarn workers of toxic gas levels. A range of intelligent sensor technologies have been developed which are designed to detect almost any harmful gas that firefighters might be exposed to on the job. This has seen a dramatic reduction in fatalities and injuries, once accepted as an occupational hazard. Having a gas monitor close at hand provides the required level of protection if it is coupled with a clear understanding of how to use the equipment and training for the call-out scenario faced.
The Evolution of Gas Detection
The first gas monitor, introduced in the 1920s, was a device with a valve that indicated methane levels in the atmosphere. The level was detected through a catalytic diffusion sensor which burned the gas inside it to provide an accurate reading. However, each time the user wanted to see how much methane was present, they had to manually press a button on the monitor. Today, the focus has moved to developing monitor and sensing technologies to address the market demand for increasing gas sensing range, performance and reliability. Significant investment is also being made in developing solutions that are easy to use and maintain, lowering the cost of ownership for brigades and ensuring higher user acceptance in compliance with legislation. Global regulatory standards ensure that detectors are safe for use in hazardous environments, while performance standards provide a benchmark for toxic and combustible gas detection capabilities.
A range of sophisticated portable gas monitors is now available that can detect and measure the multiple hazardous gases firefighters can be exposed to throughout their job. These monitors use a range of sensors including infrared, catalytic bead, electrochemical, photo-ionization and metal oxide semi-conductor technologies. Significant enhancements have also been made in relation to the usability and reliability of monitors. Most recently there has been a trend towards the development of smarter monitors that have advanced diagnostics capabilities that can transmit data and information over wired and wireless communications protocols. As these technologies and standards continue to evolve, the number of incidents associated with exposure to harmful levels of toxic and combustible gases will continue to decrease
For years Scott Safety has been at the forefront of these innovations, offering leading gas detection products that focus on three key areas: smarter high performance devices, enhanced connectivity, and improved user experience. These modular, scalable technology platforms have comprehensive global performance and reliability approvals. The Scott Safety Protégé is a good example. This technologically advanced, hand-held, durable multi-gas monitor detects oxygen, combustibles, hydrogen sulphide and/or carbon monoxide in emergency situations. Certified to the highest possible global performance standards, the Protégé is ergonomically designed to fit in the palm of the hand and can be used in the harshest conditions. It is also perfectly suited for confined spaces applications when configured with its optional pump.
Know Your Gases
Even the most common gases can have a devastating effect if present in the atmosphere at high enough levels. Each gas has a recommended exposure limit that can be broken down into a permissible exposure limit, short term exposure limit and threshold limit value. Scott Safety offers a ‘Gas Detection Reference Guide’ that lists the different gases, possible effects, and exposure limits to help others understand potential gas risks and implications.
In an emergency response scenario, individuals are commonly exposed to Carbon Monoxide (CO), Hydrogen Cyanide (HCN) and Hydrogen Sulfide (H2S). In confined spaces and non-ventilated areas without a monitor, a non-protected individual could be exposed to a potentially fatal dose of any or all of these. CO is often referred to as the ‘killer gas’ and is found in elevated levels at every fire, regardless of what is burning. It works as an asphyxiant which makes haemoglobin in the blood-stream more likely to carry CO around the body than oxygen. Too much exposure to CO can result in a condition called carboxyhemoglobin. Instead of delivering oxygen to the cells in the body, the blood delivers CO. This can lead to hypoxia, a shortage of oxygen in the body, followed by severe confusion, combativeness, and even death. Once a fire has been extinguished, harmful gases can often still be found on site, collected in air pockets within debris piles. If disturbed, this can pose an additional risk to firefighters in the surrounding area.
During the growth phase of a fire, harmful gases rise to the structure’s ceiling, where they accumulate and begin creating high levels of gas pressure. Pressurisation of the room causes smoke and gases to push out of these bounds. However, once the fire is extinguished, the process reverses itself. As gases cool, they become dense and move downward in the environment. This is a potential source of toxic exposure and makes continuous monitoring a vital requirement to ensuring that firefighters remain protected.
To protect yourself and your team, atmospheric monitoring should be a continuous exercise, during the initial stages of the fire and throughout the overhaul process as gases will travel throughout the fire scene. For absolute protection, SCBAs should be worn and used throughout. Scott Safety’s ProPak Self Contained Breathing Apparatus (SCBA) series that includes the ProPak-f and ProPak-fx is designed to meet the specific demands of the professional firefighter, requiring a high specification BA set. Offering unequalled performance and user comfort, these SCBA models play a crucial role in reducing user burden and have been approved to EN137:2006 Type2, incorporating the stringent Full Flame Engulfment Test.
Thinking Outside the Confined Spaces Box
While open spaces present gas risks, confined spaces are an even greater risk of hazardous gases, fumes and vapours building up in the atmosphere. A confined space is defined as any enclosed space where there is a risk of death or serious injury from hazardous substances or dangerous conditions. While some confined spaces may be obvious, others may be less so but can be equally dangerous. For example, a firefighter visiting a house for a building check may encounter a carbon monoxide leak. As a result, the building becomes a confined space and any individuals inhabiting this space are now at threat.
Firefighters are often required to enter confined spaces, presenting an additional workplace hazard. As the risk of fatality is significantly increased if an individual is unable to recognise a confined space and its dangers, training on safe systems of work is essential. The Confined Spaces Regulations (1997) state that employers have a legal duty to ensure that a safe system of work is implemented and that there is realistic training provided to those working in confined spaces. The fire service is no exception and a risk assessment should be mandatory. Plans can then be written to address high risk activities or scenarios.
Confined spaces offer a variety of potential hazards. Access is usually limited, they are often poorly ventilated and not only can they contain combustible gases and other harmful substances, but escape or rescue from them can be difficult. Firefighters face potential dangers including exposure to toxic gases or vapours which can poison or suffocate. Oxygen deficiency is also a major hazard and can initially cause drowsiness. It can also lead to euphoria, preventing the victim from realising the dangers before it’s too late. Dangers can also arise in confined spaces because of the build up of flammable gases or vapours that can burn or explode, causing liquids or solids to suddenly fill the space, resulting in suffocation or entrapment. Respiratory protection, including airline equipment and SCBA such as the ProPak-fx, provides the required level of high specification protection to keep firefighters safe in these hazardous environments.
It is essential that the atmosphere is tested before entering any confined area and monitored throughout using appropriate gas detection instruments. Scott Safety’s portable gas monitors, Protégé and Protégé ZM enable continuous monitoring and assessment of levels of hazardous gases.
Selecting the Right Gas Monitor
There are a wide range of gas monitors available that will detect harmful gases during risk assessment. For example, if an officer is performing a non-fire rescue where someone may have collapsed due to the CO level in the atmosphere, or performing a home safety visit where the CO level is unknown, a single gas detector is sufficient. However, if working in a confined space, a multi-gas monitor is essential to detect the risk posed by a number of potential gases that could be present. In almost all cases, consideration needs to be given to the presence of four main gases: methane, hydrogen sulphide, carbon monoxide and oxygen. Monitoring for the presence of one gas will not provide sufficient protection from the potential effects of other gases on the body if present in the atmosphere. These gases are either toxic and can affect the lungs, cause illness or poisoning or are combustible, causing risk of explosion in combination with oxygen.
As with all safety equipment, unless you know how to use it properly you may not benefit from the protection the equipment can provide. It is important that you understand how to use the equipment and how to react if it alerts you to the presence of gas. It’s not as simple as just turning on the gas detector. If you’re working in a confined space, then confined space training that includes gas detection should be included.
Regular calibration and servicing should also be required to ensure monitors are in good condition and functioning correctly in order to protect the firefighter. Putting a servicing routine in place will instil confidence that the gas detection method selected is working and fit for purpose.
The importance of understanding the risks, putting gas monitoring procedures in place and adequately protecting against residual risks cannot be underestimated when it comes to protecting firefighters. The old adage, ‘failing to prepare is preparing to fail’ is true. Taking adequate precautions saves lives.
For more information, go to www.scottsafety.com/emea
About the Author
Milton Peters is Global Product Line Manager at Tyco.
