FR and AR Clothing Difference Explained

For many years the NFPA 70E referred to the term FR to mean flame resistant for clothing in circumstances when a person could be subject to an ignition source and the clothing would self-extinguish once a person is removed from the flame source.
In the 2012 edition of the NFPA 70E the term AR (arc rated) was introduced and still causes some confusion as to what the difference is between the terms FR and AR.

These terms are assigned to fabric that has been tested to qualify to certain conditions of exposure and are rated as such then used to construct the PPE clothing.
Basically arc rated fabrics meet the performance requirements to get the AR rating but also meet the same requirements as the FR rating. On the other hand the FR rated fabric can but does not always meet the AR requirements.

To determine what the difference is between the FR and AR terms following is an explanation to help you understand.

  • FR fabrics meet the requirements for flash fire in that the fabric will self-extinguish once removed from the flame source. The NFPA 2112 for flash fire standard provides minimum requirements for the design, construction, evaluation, and certification of flame-resistant garments for use by industrial personnel.
    Most all fabric sold these days do have an arc rating also but it is not guaranteed that all fabric sold does which is so important to watch out for.
  • For AR (arc rated) fabrics these are classed as having the NFPA 70E flash fire qualifications but also have an arc rating using the ASTM F1959 test method and shown as a (cal/cm2) on the fabric lable.

When referring the FR (flame resistant) the intent is that once a person is removed from the flame source the garment will self-extinguish the fire. Most injuries occur when a person is exposed to an arc flash or flash fire and are wearing a fuel source such as cotton so what happens is the fabric continues to burn even when removed from the fire.

In regards to possible incidents concerning an electrical arc flash the highest possible arc flash must be determined by calculations to meet the requirements set for in the NFPA 70E. Protective AR clothing is then worn that exceeds the maximum exposure and this is usually determined by the protective insulated factor assigned to the fabric through testing at the production level.

This is why it is so very important to purchase garments that are tested and meet the requirements for being flame resistance for the life of the garment and will not wash out. Garments labelled as good for 25 washes are very dangerous as it is difficult to put in a system that counts the number of washed that have taken place and your life is not worth relying on guess work.

Remember that purchasing both FR and AR dual hazard PPE from a reliable and trusted source is so very important so one can know they are protected and can return home to their family at the end of the day.

 

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Terry Smeader

Distributor of Nomex, Flame Resistant Safety Clothing and Arc Flash Protection.

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