Control the risk

Simulation technologies

Operational fires remain the most common setting for deaths among firefighters in the UK. Fire and rescue services are therefore encouraged to create realistic live fire training exercises that are as close to conditions experienced or anticipated in an operational fire. As mentioned in the previous article, this must be counterbalanced by the duty to safeguard the health and safety of CFBI staff, and eliminate risks where possible while still achieving operational competence among firefighters.

Commercially developed simulation technologies provide an opportunity to complement live fire training, while engaging trainee firefighters and passing on the sort of operational competencies that do not need live fire to be carried out. Fully immersive virtual reality systems are available on the market that can simulate a variety of fire events and conditions.

This can be followed, for example, by consecutive ‘step wise’ progress to amber lighting and other digital technologies, synthetic smoke with artificial heating, and liquid petroleum gas (LPG) fires – before progressing to live fires with greater fuel loads:

• virtual reality environment
• amber lighting and digital technologies
• synthetic smoke +/- artificial heating
• LPG fires
• live fire training exercises

Following this trajectory provides trainee firefighters with the opportunity to achieve the required complement of operational competencies, while minimising the risks and hazards associated with live fires. This ‘quality not quantity’ approach to firefighter training could also help cement the emphasis placed by instructors on the hazards and risks posed by live fires, and ‘ignite’ an interest among them to safeguard their health and wellbeing through risk management.

Materials substitution

As discussed in the previous article’s look at smoke and carcinogenic chemicals, elevated levels of polycyclic aromatic hydrocarbon (PAH) metabolites were detected in the urine of instructors exposed to live fires during training. Exposures were highest with the use of oriented strand board (OSB), followed by straw and pallet.

This is significant because – for example – the warranty on the newly constructed firehouse in Cardiff Gate, where research for these articles was undertaken, is dependent on the exclusive use of OSB as the fuel load during live fire training. It may also be the case for other firehouses in the UK and Europe.

Nonetheless, safer alternatives to OSB should be considered and appropriate structural adjustments made to a firehouse if the use of OSB risks the health and wellbeing of staff. Based on suspected dermal exposure to PAHs, propane is the least toxic fuel load when compared to several other materials routinely used in training fires.

Engineering controls

Carbonaceous fire training units should be designed by a licensed design professional⁷. Live fire training centres are increasingly constructed as a ‘shell within a shell’ unit. These enclosed training units have an inbuilt ventilation and afterburner system. The system extracts the carbonaceous smoke gases and particles and then burns them a second time at approximately 850°C to 950°C, with propane or natural gas, resulting in air that is up to 99.5% clean.

That is comparable to the Live Fire Training Unit at the Training and Development Centre in Cardiff Gate (see the image below), one of only two in operation in the UK presently. At the end of the ventilation and purification cycle, a heat haze is visible from the ventilation exhaust. No soot or particulate matter is visible in the immediate environment surrounding the firehouse. This reduces smoke exposure by inhalation (and dermal absorption) in the environment immediately outside the firehouse where self contained breathing apparatus (SCBA) or respirators are not routinely worn by CFBIs⁸.

In addition to ventilation and smoke purification systems, modern day live fire training units have control rooms neighbouring, but detached from, the firehouse. These control rooms have a remote control and supervisory screen panel. Thermal cameras enable the CFBI to follow the evolution of the live fire training session remotely from within the control room, even when visibility is poor.

The control panel is equipped with a start stop switch, compartment temperature indicators, controls for a smoke generator, safety evacuation lighting, audio and visual alarms and an emergency shutdown button. The temperature monitoring system ‘ensures that no life-threatening temperatures are reached within the hot training room’⁹.

Fires can be lit remotely via LPG once the fuel load is assembled. This engineering control, if implemented alongside a suitable procedural control, reduces the frequency and/or duration of live fire training sessions requiring CFBI exposure to the heat loads and hazards of compartment fires.

Administrative controls

Work/rest cycles

Results and analysis of a UK wide survey completed by 130 CFBIs into their working practices reported that from the feedback of almost half of the CFBIs surveyed, in the instructors’ experience of between two and ten live fire training sessions per week, management did not have a ‘hot wear’ exposure limit. The survey also demonstrated that instructors’ self reported measuring of symptoms or illness were associated with the number of wears.

Blood sampling of CFBIs over the limit of nine wears per month demonstrated levels of the inflammatory cytokine IL-6 over the reference range and instructors were 15.74 times more likely to report symptoms of
ill health. An example of a work/rest cycle scoring system for CFBIs can be seen in Figure 1 above. In addition to avoiding more than nine ‘hot wears’ in a month, an instructor scoring system may be the most discerning risk mitigation tool by which to schedule work/rest cycles and wellbeing breaks. For example, an instructor scores their ‘hot wear’ (breathing apparatus with heat exposure) based on their level of physical exertion, using a points grade system of either one or two (see also Figure 1 above).

Once six points have been reached on consecutive days of live fire heat exposure, an instructor must take a two day wellbeing break before resuming ‘hot wears’.

Continuous self monitoring

Physiological status monitors are integrated into the instructor’s personal protective equipment (PPE) and give live feedback on heart and respiratory rate. When complemented with the use of decision trees based on data driven predictive models, indications of heat strain are detected and may prevent an instructor from crossing the ‘threshold’ into heat stress.

Firehouse behaviour

CFBIs should adopt a posture that minimises body surface area to heat exposure, such as sitting low or kneeling. Doorways should also be avoided during periods of fire observation, as the fire’s laminar heat and steam exhaust passes through open doorways as visualised on infrared cameras.

Decision making

Cohen-Hatton and Honey showed that setting goals and anticipating the consequences of different action plans can affect the nature of decision making across a variety of firefighting environments, including live burns. Although study participants were operational commanders, there are applications here for CFBIs as the study demonstrates that goal orientated decision making improves communication and safety.

Heat tolerance test

Occupational heat tolerance tests are intended to assess an individual’s anticipated physiological response to heat exposure and identify susceptibility to heat related illness. These may form a helpful part of pre employment medicals and ongoing health surveillance.

Acclimatisation programmes

An acclimatised individual is less susceptible to heat related illness. Various heat acclimation programmes exist and selecting a sensible, evidence based approach that facilitates breaks among CFBIs should be adopted.

PPE provision

CFBIs should be supplied with adequate sets of PPE. A practical example of this is provided in the bullet points further down. In addition, suitable provision for storage and laundering of contaminated PPE is essential to prevent cross contamination. Personal hygiene and washdown following carbonaceous exposure are also recommended.

The use of undergloves during live fire training reduced PAHs on instructors’ hands by 80%. The choice of undergarments worn by CFBIs may also affect their IL-6 inflammatory response and therefore subsequent cardiovascular risk, with a wicking base layer or shorts and t-shirt being favoured.

For fire protection, the use of flash hoods is required. Flash hoods should be both breathable in order to reduce heat strain, and particulate blocking, to reduce dermal absorption. The PPE supply for CFBIs at the Live Fire Training Unit in Cardiff Gate was as follows:

• six full sets of fire kit (four more than standard allocation)
• access to a stock of flash hoods that allow for a clean one to be used for each separate carbonaceous breathing apparatus wear
• six boiler suits/overalls with long sleeves (a clean one for each separate day of carbonaceous fire training)
• negative pressure face mask, complete with separate filters for areas containing carbon ashes and areas containing synthetic smoke

Future research could investigate the impact of design interventions to mitigate heat strain and the inflammatory markers associated with cardiovascular disease. Further primary studies are also required to assess the efficacy of PPE in reducing dermal absorption of contaminants, and appropriate practices established where evidence already exists.

More qualitative studies and fieldwork are required in different jurisdictions to better understand the perceived hazards and the actual concerns CFBIs have regarding their work, as well as how to mitigate these.