Reducing heat stress during firefighting

Heat stress is a common worry for firefighters, especially during the summertime. However, there are technologies available on the market to support the reduction of heat stress. In this blog, we take a look at some of your options.

Understanding and combatting heat stress

As we know, fire suits are a particularly heavy duty form of PPE. The many layers required within fire suits to keep firefighters safe can also have the side effect of decreasing breathability. We also know that there are a range of garments employed by firefighters, based on setting:

Stationwear: worn at fire departments
Wildland: worn in outdoor settings
Structural suit: worn while in active duty at the site of a fire

A major element of reducing heat stress is about making sure the right garment is worn in the right situation. Within each different type of garment, too, technologies have been improved to make them more comfortable and breathable for the wearer. Let’s take a deeper look into the different types of garments.

Stationwear

Stationwear generally refers to garments such as uniforms, worn at fire stations. Typically, we’ve seen stationwear make use of synthetic fibres; but this is not ideal as it not very breathable.

A technology that we recommend for stationwear is inherent FR blends that utilise a blend of quick-drying fibres and moisture absorbing fibres such as Tencel®, that pull moisture and heat away from the body resulting in an evaporative, cooling effect. Tencel® is highly sustainable, soft and breathable — making it an excellent option for day-to-day wear at fire stations.

Wildland

When it comes to garments that are suitable for wildland settings, what the wearer ideally needs is to feel cool and dry, but at the same protected from the elements. Lightness is key. Garments made with aramid are therefore not suitable, as they are not the most breathable and moisture-absorbing.

In the past, wildland garments consisted of a two-layer system. Now, there is the option of one-layer systems, with similar technology. The two-layer system features two fabrics and provides better thermal protection.

Studies and practical experience have shown that it is extremely important to wear single-layered garments in this application and to use materials that not only meet the requirements for thermal and mechanical properties, but also offer excellent moisture management. Breathable garments that keep the firefighter dry are key to significantly increasing safety in these extreme situations.

Structural suit

Structural suits consist of the three layers:

The outer layer: this is the first line of defence and provides thermal protection. If this layer tears, the suit must immediately be repaired or returned.
The moisture barrier: this blocks chemicals, pathogens, oils and other contaminants. It is not particularly breathable.
The inner layer: this is what sits directly next to the skin. As the wearer will inevitably sweat, ideally we want the inner layer to pull this sweat away from the skin.

With all these three layers working in tandem, structural suits are often big, heavy, and bulky. Consider that any extra work or effort required by the wearer to move in their garment will lead to more sweat, more exertion and higher chance of heat stress. Therefore, by improving the flexibility of materials and their range of motion, we can make these suits more comfortable and wearer-friendly — and in the process, reduce the chance of heat stress. Furthermore, we want to work with materials that improve durability and airflow — so lighter weight materials which don’t compromise on protection are ideal.

Balancing protection and breathability

Above all else, the garments worn by firefighters must conform to certain standards and certifications, to keep the wearer safe. The core parameter for all fire suits in the Ret measurement — which measures the amount of heat and moisture released. It also tells us how breathable and comfortable a suit is: the higher the number, the less breathable. Garment manufacturers can provide the Ret measurement for their suits.

When making your selection, it’s key to consider the Ret measurement, alongside the types of fibres used within the garment. And, though it may seem simple, it’s always worth considering if the right garment is being used within the right application — potentially saving problems further down the line.