NFPA 2112 Pass/Fail Test Series Part 3: The Vertical Flame 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:
- The Manikin Test
- The Heat Transfer Performance Test
- The Vertical Flame Test
- The Thermal Shrinkage Test
This is our third installment of this blog series. In our previous posts we covered the Manikin Test, and the Heat Transfer Performance Test. The next test we will cover is called the Vertical Flame Test (ASTM D6413). This test is extremely important to the FR industry in that it determines whether the fabric can be classified as flame resistant.
To begin, we start with a 12” long, 3” wide piece of fabric. We hang the fabric vertically, then expose the bottom 3” edge of this fabric to a flame for 12 seconds. If the fabric ignites and continues to burn until it is consumed (BEL- Burn Entire Length), then clearly it is not flame resistant. If it does not continue to burn after the vertical flame is removed then we measure the damaged area, called char length. Char length is the portion of the blackened area that will easily tear, and standards set maximum length pass/fail criteria.
The measurements obtained in this test are:
- Char length – the length of the char from the exposed flame
- After-flame – does any flame remain after the test ends?
- After-glow – is there any heat glow which remains after the test ends?
Both after-flame and after-glow are measured and recorded but are not pass/fail parameters. Char length on the other hand is pass/fail. The maximum acceptable char is different depending on the standard. NFPA 2112 the flash fire standard requires a char length of 4” or less, whereas ASTM F1506 which is the arc flash standard requires a char length of 6” or less.
The test is the repeated five times and the data is averaged to determine the char length or “test results” for that fabric.
The Vertical Flame Test is essential to analyzing the relative protective performance of a specific fabric or garment. These results guide workers to garments that offer the protection they need on the job. ALERT-this is an excellent test for standard apparel fabrics, but is not well suited to analyzing rainwear fabrics, because they can shrink away from the flame. Tyndale recommends ASTM F1891 (arc) and ASTM F2733 (fire) for FR rainwear.
Want to learn more? Browse our blog posts for more helpful information about NFPA 2112 and the answers to other frequently-asked questions. Don’t miss Part 4 which highlights the last test required for a fabric or garment to be certified as NFPA 2112 compliant.
