There is a strong misconception in the workplace that all flame resistant (FR) clothing is designed for all momentary thermal hazards. A momentary thermal hazard is an event which includes some type of heat or flame lasting for a short duration of time. Each momentary thermal hazard has its own characteristics and therefore requires specific protection needs from FR clothing to protect the worker.
First let’s look at two of the most common momentary thermal hazards in the workplace today, arc flash and flash fire. These two hazards are vastly different in duration and temperature. Flash fire is defined in NFPA 2112 as a fast moving wall of flame lasting up to 3 seconds and having temperatures ranging from 1200˚ to 1900˚. Arc flash, on the other hand, has a duration that is defined in milliseconds. There are 60 milliseconds in a second and an arc flash commonly lasts only 2 or 3 milliseconds. However an arc flash can have temperatures up to 34,000˚. That’s 4 times hotter than the surface of the sun.
Each hazard is violent in their aspects but, as you can see, they each have very different protection needs. Because of this it is extremely important that one understands which hazard they are trying to protect the worker from and ensure the proper flame resistant garments are selected.
To simplify things we should step back and look at how clothing is identified as flame resistant. We need to understand that the standards for determining FR performance are not garment standards. Meaning they are not testing garments at all. They are testing fabrics. That being said we can look at FR fabrics as a tree. Before ever a fabric can be called FR it must pass a vertical flame test known as ASTM F6413. If a fabric passes this test it is now able to be called flame resistant fabric. This is the trunk of the tree. Now this flame resistant fabric can be tested to specific hazards such as flash fire, arc flash, fire fighter bunker gear, wild land fire protection, etc. These hazards are the branches of the tree. Each has its own dangers and parameters and because of this they each require very specific types of protection from flame resistant fabrics. In some cases the standards require the fabric to be made into a garment and tested and in other cases the standards require swatches of fabric be tested. It all depends on how best to determine the level of protection needed for that hazard. Once a fabric has passed or been given a rating it can then be cut and sewn into garments and show the proper labeling to inform the worker they have selected the correct garment for the hazard they are protecting themselves from.
Unfortunately due to a lack of understanding and misinterpretation of standards, improper selection of FR clothing is commonplace in the industry. As an example let’s look at the oil & gas industry. Most companies in this industry are concerned with meeting the OSHA requirements for FR clothing worn in an environment where flash fire is a known hazard in order to protect their employees. This hazard requires that fabric be tested to a test method known as ASTM F1930. In this test an extra-large coverall is made out of an FR fabric, placed on a mannequin that has calorimeters, and exposed to flame. This test does not rate the fabric. After being exposed to the flame data is collected from the mannequin and a body burn percentage is predicted. If the prediction is that less than 50% of the mannequin received 2nd and 3rd burns the fabric passes. Again there is no rating or level given only pass or fail. By passing this test the fabric then meets the requirements of NFPA 2112. A garment is made out of the fabric and “2112” is displayed on the garment to let the wearer know it has passed this test and is designed to protect the worker in a flash fire hazard. However these same companies often who are only concerned with flash fire protection require a “CAT 2” or “PPE 2” label on these garments as well which has no relevance to flash fire at all.
CAT 2 or PPE 2 is a label put on clothing that has been arc rated using a test method known as ASTM F1959 and is designed for protecting workers in an electrical arc flash. The test requires swatches of fabric to be exposed to different levels of incident energy. This is not a pass or fail test. The fabric is given a rating known as Arc Thermal Performance Value (ATPV). The CAT 2 or PPE 2 comes from a section of the standard called NFPA 70E which identifies specific hazard levels for electrical workers and then provides 4 levels of personal protective equipment (PPE). PPE 2 is generally considered to be the most common level. As a failsafe many companies in the electrical industry require their clothing to be a minimum of CAT 2 or PPE 2. Another standard known as ASTM F1506, defines the labeling requirements for arc rated (AR) clothing. ASTM F1506 requires that certain information be included on the label placed inside the garment including the ATPV rating of the fabric. This in turn lets the wearer know what rating their clothing has been given. Nowhere in this standard, or any other standard or regulation, does it require that CAT 2 or PPE 2, or any other level 2 designation, be put on the outside of a garment. But, because we have come to identify this label as a way of identifying safe FR clothing, many companies will not buy FR clothing if it does not have this somewhere on the garment.
In short many companies, only concerned with flash fire protection, incorrectly assume the garment will only protect the worker if that garment has a CAT 2 or PPE 2 label and will not approve clothing that does not have a CAT 2 or PPE 2 rating even though this label is for electrical arc flash protection and has nothing to do with flash fire. NFPA 2112 does not require a rating for clothing. Nor is there a “level 2” requirement anywhere in the standard. It does require that is passes ASTM F1930. Oddly very few if any companies, wishing to protect their workers from arc flash, require “2112” identification. When they do require it they are looking to protect their workers from both flash fire and arc flash. This type of clothing is known as dual hazard protection. In this case the clothing or fabric has been tested to ASTM F1959 for arc rating and ASTM F1930 for flash fire to ensure the worker’s safety in either arc flash or flash fire hazards. This is completely different than selecting FR clothing which is not tested to the hazard required as noted in this article.
One of the biggest mistakes made in the workplace is in believing that, because a garment is flame resistant, it must be safe for all hazards. This simply is not the case. In fact selecting FR garments not designed for the correct hazard could expose the worker to greater injury. To avoid this asses your workplace environment and identify which momentary thermal hazards exist. Remember it is very possible to have multiple thermal hazards. Then only select clothing that has the proper testing and identification as required by the standards for each hazard.