NFPA 1971: Structural Gear


NFPA 1971 certification requires the greatest number of tests, across the widest range of protections (heat, flame, liquids, viral penetration, and durability tests). Whether it's your turnout gear, your boots or your gloves, rigorous tests are performed to ensure the product can withstand the extreme temperatures and the extreme beating they take when on the job.

Amongst the most well-known and discussed test results are Thermal Protective Performance (TPP) and Total Heat Loss (THL). All Turnout Gear fabric composites are tested and given a TPP & THL rating; a "composite" refers to the 3-layer combination of shell fabric, moisture barrier and thermal liner.


The TPP test is done to simulate a flashover. Before the NFPA adopted this test in 1986, thermal protection was measured by the thickness of the 3 layers of fabric. The current test method measures the amount of time it takes for the flame's heat to pass through the 3 layers and cause a second degree burn. The minimum TPP score is 35, which based on the formula used, would mean it would take 17.5 seconds (2 cal/cm2-sec times 17.5).


THL measures the composite's ability to let both body heat and vapor escape. The NFPA did not require a THL test until the 2003 edition, mainly because there was no feasible test method. With overexertion/stress/medical still being the #1 cause of death of on-duty firefighters, it is obvious that this test is every bit as important as TPP. The minimum THL score is 205. Small differences in THL scores are usually unnoticeable to the wearer; it's suggested it takes a 20 to 25 point difference to actually be felt by the wearer.

TPP Test Beginning
TPP Test Beginning
TPP Testing
Composite Cooling, Post-Test
Composite After TPP Test
Composite After TPP Test

There is usually an inverse relationship between TPP and THL; a thicker, heavier garment will have the highest Thermal Protective Performance but lower heat loss, and a thinner, lighter garment will have a higher THL rating, but will score lower on TPP.

When building your own custom turnout gear in FireWriter3, you can explore the TPP/THL ratings of different combinations of outer shell, thermal, and moisture barrier to find the composite that's right for you.  The TPP/THL displays at the top of the screen, and as you play around with selecting different materials you can watch how the scores change.

In addition to TPP, there are many other tests performed to the materials and the entire ensemble to ensure protection against heat and flame. There are also several tests for overall durability such as seam strength and tear resistance tests.

Click to expand the following section to learn more about all the tests Turnout Gear must pass to be NFPA 1971 certified.

Helmets, Hoods, Gloves & Boots

From head to toe, every article of PPE worn by a firefighter is held to the high standards of NFPA 1971.  

Each item undergoes different tests that are designed to mimic how that specific product is used in the field.  Testing in multiple scenarios and simulating realistic conditions is vital to ensuring the product will protect the firefighter on the job and perform correctly in every possible situation.

Just like Turnout Gear, all NFPA 1971 certified products are tested to ensure protection from heat and flame, in addition to tests for durability, safety, and function.

Testing glove in oven
Testing glove in oven

Expand the following sections to learn more about the tests each item must pass to be NFPA 1971 certified.