Hitting back at heat stress

Hitting back at heat stress

Over recent years, studies have shown that heat stress is especially life-threatening for firefighters and is the number-one cause of firefighter casualties.  Paul Gibson, International Sales Manager at Bristol Uniforms, looks at the latest advances in the fight against heat stress.

Heat stress is a potentially fatal condition caused by a dangerous rise in core body temperature, which can be brought on when faced with the intense heat of a fire, and exacerbated with physical exertion. It increases muscular fatigue and interferes with cognitive function, causing a serious loss of balance and co-ordination and may also increase cardiovascular strain, which can lead to cardiac arrest and death.

Research from studies such as Firefighter Fatalities and Injuries: The Role of Heat Stress and PPE (University of Illinois USA, 2008) have shown that more firefighters die in the line of duty from cardiac arrest than from any other cause. And in addition to the elevated risk of cardiac arrest, slips and falls brought on by loss of co-ordination can prove just as fatal in a firefighter’s hostile working environment.

Now that the dangers of heat stress are better understood, firefighters across the world have adopted a range of preventative measures when attending operations. Hydration is particularly important, and firefighters on the front line are routinely provided with bottled drinking water. Time spent in the heat of a fire is closely monitored and restricted, with crews rotating roles and sharing heavy physical work.

New products & technologies

PPE manufacturers, designers and their suppliers also realise they have a vital role to play in developing protective clothing that keeps the body as cool as possible. For us, the fight against heat stress is ongoing. We have worked together in recent years to make significant strides in devising successful solutions to safeguard against heat stress, and it continues to be a key focus in the development of new products and technologies.

In the past, materials that protect against external heat and flame have been hot and heavy, preventing burns but trapping body heat and moisture. Over the years, innovations from leading fibre and fabric manufacturers, such as WL Gore, Hainsworth, PBI Performance Products and DuPont, have helped PPE manufacturers to produce multi-layered garments that protect from inside and out, allowing internal heat and moisture to escape, whilst keeping the body cool and dry. A select combination of fabrics can offer resistance to fire, increased breathability, control of moisture, and a lighter weight – all of which help to reduce the occurrence of heat stress.

WL Gore has recently developed a brand new fabric which is particularly lightweight and offers unprecedented levels of breathability and thermal protection, helping to prevent dangerous increases in core body temperature. The Goretex Moisture barrier with new Gore Parallon System incorporates the most advanced moisture management technology available. In recent trials it lost only 4% of its thermal protection when wet and displayed the lowest resistance to the evaporation of sweat. At Bristol, we are now offering customers this ground-breaking new technology as part of our XFlex range.

New developments in combatting heat stress are not just confined to structural PPE. Search and Rescue operations often take place once the immediate danger of flame is removed, with USAR or technical rescue teams entering enclosed and confined spaces, where high temperatures are a hazard.

Bristol’s RescueFlex offers a high level of flexibility to enable manoeuvrability in confined spaces, and is lightweight to minimise heat stress. It is now available in new Gore® Varde fabrics, specifically developed to offer significantly more comfort and flexibility in rescue operations. Gore® Varde garments provide a high level of protection against wind, water and flame in just one light, breathable layer. The durable waterproof and windproof qualities of the fabric, including low water pick-up and quick re-dry properties, ensure protection from the elements on the outside.

At the same time, sweat is able to pass through the fabric from the inside, keeping the wearer dry and reducing the risk of heat stress. The fabric is also self-extinguishing and flame retardant, protecting firefighters from the possible hazard of unexpected fire during a rescue operation, and enabling crucial escape time.

Design solutions

Along with fabric technology, the design and style of a garment can also play a crucial role in contributing to a firefighters’ safety and minimising heat stress. The work of a firefighter is often very physical, in a hot and hostile environment. Protective clothing that is ergonomic and easy to move in makes the role less strenuous, and reduces the build-up of body heat and sweat.

Garments need to be designed that work with firefighters rather than against them. A structural firefighting kit is lightweight, breathable and ergonomic. With its distinctive sports styling and suitable for a range of operations, the XFlex range has been selected by Qatar and UAE Civil Defence Forces, but its flexibility means it is just as suitable for industrial firefighters, such as at the Abu Dhabi Company (ADCO).

As an extension of the XFlex range, a unique layered concept has been created using a set of three garments to offer even greater protection against heat stress. LayerFlex consists of standard structural XFlex trousers, a specially adapted XFlex outer jacket, and RescueFlex jacket which is worn underneath.

LayerFlex is particularly useful when a fire service is faced with a range of operations requiring varying levels of protection. All three garments would be worn to attend a house fire or industrial petrochemical fire, whereas for a road traffic accident the mid-layer coat and trouser combination would be more suitable, with the top coat removed. This solution improves ergonomics and comfort, and avoids unnecessary layers of clothing.

By working together in this way, the entire fire industry has made great strides in fighting back against the dangers of heat stress. It is likely that lives have been saved as a result. Whilst the full physiological effects and implications of heat stress become clearer with ongoing research, firefighters can be assured that the industry will continue to strive to develop new designs, technologies and innovations to offer maximum levels of protection.


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