What Is Firefighter Turnout Gear Made Of? | Three-Layer Composite

Firefighter turnout gear is a three-layer composite — an outer shell, a moisture barrier, and a thermal liner — with each layer built from specialized heat-resistant materials certified under NFPA 1971 for structural firefighting.

In the United States, the standard firefighter ensemble goes by several names — bunker gear, turnout gear, or full structural firefighting protective equipment — but the build is always the same: a carefully engineered stack of three distinct layers. Understanding what each layer is made of, and why it matters, is essential whether you are buying gear for a department, researching what protects your family member, or picking a meaningful gift for a firefighter.

The Three Layers Explained

Every NFPA 1971-certified turnout coat or pant relies on a specific layer order. The outer shell takes the direct hit from flames and abrasion. Below it, the moisture barrier blocks water, steam, and hazardous liquids while letting sweat vapor escape. Closest to the body, the thermal liner traps air to slow heat transfer to the skin. These layers are never interchangeable — each one serves a distinct safety function.

Outer Shell Materials

The visible exterior layer is woven from inherently flame-resistant technical fibers. Most common are aramid blends — materials like Nomex (meta-aramid) and Kevlar (para-aramid) — along with PBI (polybenzimidazole), PBO, or combinations of these fibers. Fabric weights typically fall between 7.0 and 7.8 ounces per square yard, and the weave may be ripstop, plain, or twill depending on the manufacturer. Many outer shells also include a durable water-repellent finish, historically PFAS-based, though non-PFAS alternatives are increasingly available.

PBI is prized for its extreme heat resistance but is expensive, which is why aramid blends dominate the market. Regardless of the fiber choice, the outer shell is engineered for flame resistance, tear strength, abrasion resistance, and flexibility — not just to survive a fire, but to let the firefighter move freely inside it.

If you are looking for a thoughtful item for someone who wears this gear daily, check out our curated selection of awesome firefighter gifts that honor the profession.

Moisture Barrier and Thermal Liner

The middle layer — the moisture barrier — is a laminated membrane system. One common specification uses a fabric composed of 93% meta-aramid, 5% para-aramid, and 2% anti-static fiber, laminated with a PTFE membrane. PTFE (a fluoropolymer, best known by the brand name Teflon) creates a waterproof yet breathable seal. The barrier prevents steam burns and blocks hazardous liquids from soaking through to the wearer, but it still allows sweat vapor to escape so the firefighter does not overheat.

The thermal liner is the insulating underlayer, usually an aramid-based face cloth combined with batting or a nonwoven insulation package. This layer works by trapping air — the same basic physics as a winter coat, but with materials that will not melt or burn. Together with the other two layers, the thermal liner buys the firefighter those extra moments to escape or to work inside a burning structure.

The weight of the moisture barrier assembly is typically in the 4.7 to 5.5 OSY range, though exact numbers vary by brand and model. All three layers, including seams and reflective trim, use heat-resistant hardware and Kevlar or Nomex sewing thread to maintain integrity under extreme conditions.

Common Misconceptions About Turnout Gear Materials

A few misunderstandings keep showing up even in well-meaning articles. First: turnout gear is not a single fabric — it is three separate layers with different jobs. Second: not all gear uses the same fibers; some departments specify PBI shells for maximum heat protection, while others use aramid blends for a better balance of cost and durability. And third: the moisture barrier is not just “plastic” — it is a specialized vacuum-deposited or laminated membrane system, frequently PTFE-based, that must remain breathable while stopping steam and liquids.

There is also the PFAS question. The outer shell is often treated with a PFAS-based DWR finish (or an alternative), and the moisture barrier may itself contain fluoropolymer membranes — a point NIST has documented in detail. This is an evolving area of concern, and manufacturers are actively developing non-PFAS alternatives, but most current gear still contains some fluorinated components.