There are two distinct kinds of FR fabrics from which garments are made: inherent FR and treated FR. Inherently FR fabrics are engineered to be flame resistant for life, having the FR properties literally built in at the molecular level. The protection doesn't wash or wear out, and the garment will always be FR, no matter how long it is in use.
Treated FR fabrics go through a chemical application process that makes them FR. Over time, the FR properties will begin to degrade and become less and less protective as the wear life of the garment continues. Wear, abrasion, UV exposure, and laundering will shorten the useful wear life of a treated FR fabric. Add to this the fact that the chemical FR treatments applied to fabrics such as cotton often present significant environmental concerns about the effluents of such processes, and you can see how the cost of ownership of these garments will not look as good tomorrow as it might today.
There have also been issues with shrinkage when garments have been made with natural fibers such as cotton that have had an FR treatment applied to them. This can have a serious effect on comfort and the wear life of the garment. It may well seem wise to pay less for a garment today but if that same garment only lasts for one season, then your money will have been better spent on a longer-lasting, more durable FR solution.
The levels of protection also may differ according to which FR fabric is used in a garment. A treated FR fabric may start with a body burn percentage rating of 35 percent, but that may well increase as the FR properties began to fail. An inherently FR fabric will yield the same body burn percentage for the life of the garment. An FR garment or even FR fabrics require only a 50 percent body burn rating to be NFPA 2112 certified, so it's a good idea to investigate what the percentages are when comparing different FR solutions. Many fabrics and garments can pass the 50 percent body burn requirement, but just how a big a difference is there between a 35 percent body burn and a 15 percent body burn? The difference in percentage could mean the difference between life and death.
Nomex® is probably the best-known inherently FR fabric on the market and has long been a favored solution in many applications. But as the years have gone by, the market has seen many options that offer the same inherent protection without the usual stiffness and poor moisture management that make up the bulk of complaints about it in the field.
Oil and gas workers are doing just that: working. And their work takes them into some pretty harsh environments. Hours spent laboring under a hot sun in arid conditions can provide a quick and painful education on the importance of moisture management. Workers need a garment that will "wick," or pull the moisture away from the skin and dissipate it quickly so it can evaporate and keep the wearer cool and dry.