NFPA 2112 Pass/Fail Test Series Part 2: The Heat Transfer Performance Test

Welcome to our four-part blog series about the pass/fail testing requirements for NFPA 2112 compliance. NFPA 2112 is also known as the “flash-fire standard,” and there are four tests which a garment or fabric must pass to receive this accreditation. Watch Tyndale’s VP of Technical Scott Margolin describe this test series NFPA 2112 Pass-Fail Tests

The four tests a garment must pass to comply with NFPA 2112 are:

  1. The Manikin Test
  2. The Heat Transfer Performance Test
  3. The Vertical Flame Test
  4. The Thermal Shrinkage Test

In our previous post we covered the Manikin Test and why that test is so important when vetting flame-resistant clothing. The next test we will cover is called the Heat Transfer Performance Test. The main function of this test is to measure the insulative ability of a fabric to prevent a 2nd degree (or higher) burn. Let’s have Scott walk us through this test.


The Heat Transfer Performance test uses two different procedures to accurately quantify a fabric’s insulative ability. We first start with a piece of fabric. This fabric is suspended horizontally with a thermocouple (heat sensor) above, and the heating elements below. Two heat sources are applied the first being a burner (or flame), the second being a heating lamp. This allows the test to record the effects of both convective and radiant heat.

When the test begins, both heating elements are engaged and the sensor begins detecting temperature increase through the fabric. The sensor is calibrated to predict/record at what temperature a 2nd degree burn will occur. This sensor is set-up either in-contact with the fabric, or spaced ¼” from the fabric, which accurately represents how our clothing rests on our skin. Once the sensor records a temperature which exceeds those causing 2nd degree burns, the test immediately stops. These measurements are then converted into a calorie rating which will be reflected in the garments technical specifications.

For a fabric to pass the NFPA 2112 Heat Transfer Performance Test it requires:

  • At least 3-calorie rating in-contact, or
  • At least 6-calorie rating spaced

The Heat Transfer Performance test ensures that fabrics that pass the test offer the protection workers need on the job.

Want to learn more? Browse our blog posts for more helpful information about NFPA 2112 and the answers to other frequently-asked questions. Stay tuned for parts 3 and 4 which highlight the other tests required for a fabric or garment to be certified as NFPA 2112 compliant.

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