NFPA 701: How to Read the Test Results
26.03.2012 § Leave a Comment
(No. 3 of 3) It is very common for people to request copies of our test results, especially fire test results, for their records. I imagine they are usually just looking for the note at the bottom that says that the fabric “complies” or “meets the requirements.” When a fabric doesn’t pass the test, that’s when we start looking at the other numbers. So what do all of those numbers mean, anyway?
The first thing to know about NFPA 701 is that each test uses 10 samples or specimens. For each specimen, the testing facility collects four pieces of information:
Initial mass: Since 701 primarily bases its results on the percent of mass the fabric loses when it burns, the initial mass is critical. Each specimen is “conditioned” at a high temperature to help dry the fabric and prevent its natural moisture content from affecting the results.
Final mass: The final mass is also recorded so that the testing facility can calculate the percent of mass loss.
Afterflame: After the flame is removed from the specimen, the tester will time how long it takes for the sample to stop burning. The afterflame times do not affect whether a fabric passes or not, but they’re included to give an idea of how the samples burned.
Drip burn (or flaming drip or residues): If any part of the fabric falls off of the original sample and continues to burn, the tester will also measure how long it takes for that piece to stop burning.
The test results usually include a chart with these four measurements along with a column for the calculation of each specimen’s percent of mass loss (or percent of weight loss) and the averages for all of the categories. If the samples meet the following two criteria, they pass.
1. The average drip burn is no more than two seconds.
2. The average percent weight loss (mass loss) is no more than 40%.
Applying those two criteria, take a look at the two test summaries following. What do you think? Did they pass?
(Click the test results to see the full reports.)