Structural Fire Suit Layers Explained

A structural firefighting suit typically consists of three key layers to provide protection against heat, flames, and other hazards encountered during firefighting operations.

Outer shell

This is the outermost layer of the suit and is made of a fire-resistant material. It provides protection against direct flame exposure, radiant heat, and abrasions. Firefighting suits are constructed using various fire-resistant fibres, such as PBI, PBO, Nomex, Kermel, Conex, Twaron, Kevlar, or other unbranded materials. Each fibre has unique properties that contribute to the performance of the suit. However, no single fibre is perfect for every aspect of the suit’s design.

Therefore, manufacturers create composites using different fibres to take advantage of their strengths and mitigate their weaknesses. If a suit were constructed using only one type of fibre, it would not be suitable for firefighting operations due to its limitations. By combining different fibres, the suit can provide optimal protection against the hazards of a fire.

Moisture barrier

The moisture barrier is a layer that keeps moisture and liquids from penetrating the suit. It is typically made of a breathable material such as Gore-Tex or PTFE and is essential for maintaining the comfort of the firefighter. The moisture barrier plays a vital role in a firefighting suit, as it prevents water from penetrating the suit while allowing moisture to escape to keep the firefighter comfortable.

All seams on the moisture barrier are taped for added protection. Additionally, the moisture barrier layer provides thermal protection as it typically includes a non-woven aramid laminated to one side. It is important to regularly check the moisture barrier for damage, as any breach in the barrier can lead to serious injuries from steam burns. It is critical to ensure its durability, breathability, and waterproof capabilities.

Thermal barrier 

This layer provides insulation against heat and flames and is typically made of a material such as aramid or carbon. It is designed to prevent the transfer of heat from the outer layer to the inner layers of the suit. The thermal liner we use is our suits is the Twin Spacer.

It’s also worth noting that the Thermal liner of a suit is a critical component in its overall thermal performance. Without an effective liner, even the best outer shell would not provide adequate protection against heat and flames. Therefore, the Twin Spacer’s exceptional thermal performance, combined with its lightweight design and air gap construction, make it an ideal choice for a wide range of applications where reliable thermal protection is essential.

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