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Flame Resistant Clothing: Get 'The Facts,' not 'The Story'
The words "Inherent" and "Treated" are commonly used when referring to flame resistant (FR) fabrics, but very few people understand the relevance of the terms. A recent article published in OH&S about flame resistant clothing contained a lot of excellent information. Unfortunately, there was a section about "inherent" vs. "treated" flame resistant fabrics that was inaccurate, incomplete, and/or misleading on this topic, necessitating a review of the facts.
First and foremost, it is important to understand that "inherent" and "treated" are marketing terms with no origin in textile science and with little or no consistency of application fiber to fiber, fabric to fabric, or year to year. Sales literature frequently implies that one method is better than the other, and the marketing spin has been that treated fabrics wash or wear out, while inherent fabrics do not. Like virtually everything else in life, neither method is perfect, and each has its pros and cons, but repetition over time has created impressions in the marketplace that are simply not borne out by the facts when it comes to the leading FR fabrics.
The "inherent" fibers tend to be synthetics, and most begin as naturally occurring flammable substances (petrochemicals), not fibers. Humans must intervene, using chemistry, to engineer the fiber and the FR properties within it. Similarly, most "treated" products begin as naturally occurring flammable substances (usually cotton or other cellulosics), so nature has already taken care of the fiber portion, and humans get involved to engineer the FR.
The word inherent was not originally a textile or FR term. Its definition varies slightly from source to source, but the common thrust is "by its very nature, built-in, implicit," while "treated" is usually defined as chemical engineering to impart properties not previously present. Nature provides very few FR fibers, the most well known of which is asbestos, which is obviously not in common use in protective apparel in North America today. Conversely, all flame resistant fibers in common use today for industrial protective apparel are engineered by humans, using chemistry, to be flame resistant. What is important is not how the engineering was accomplished; what matters is that the engineering was accomplished, correctly and consistently, so that a garment is flame resistant weeks later, months later, and years later, regardless of how many times it is laundered.
What should be critically important to the ultimate end user is that the garments are flame resistant for the life of the garment. The FR protection shouldn't wash out, wear out, or fall off, and it should be there every time the garment is taken out of a locker or drawer and worn to work.
It is also critically important to look for proven products because some marketing claims are made with little or no substantiation, while others are based on tests or standards that fall far short of real-world service life and laundering conditions. Proven means different things to different people, and there is no specific definition of how it applies to FR garments. In the safety industry, "proven" should mean repeated independent laboratory evaluation and years of performance in the market, ideally through at least two replacement cycles. This means that end users have purchased, worn & washed the garment until garment replacement becomes necessary, and then re-purchased the same product. There are a wide variety of additional "issues" that arise from new and unproven FR fabrics that run the gamut from losing flame resistance after washing to being stiff heavy and uncomfortable to excessive shrinkage, extreme color fading, pilling, pre-mature wear, UV degradation, and more.
So what does inherent mean as applied to the FR clothing market? Regardless of actual definition, the value cited by virtually everyone is that "inherent" FR garments won't wash out, that they are FR for life. However, "inherency" is not the only path to engineering life-of-the-garment flame resistance.
What does "treated" mean as applied to the FR clothing market? To many, it means a fabric whose FR properties are topical and/or temporary. This may be true with some generic, unbranded "88/12 FR" and 100 percent cotton FR fabrics that have hit the market in the past five years. However, when it comes to the fabric brands that have the largest share in this category, Westex UltraSoft® and Indura®, the engineering technology results in a fabric that is guaranteed to be flame resistant for the life of the garment. This guarantee has been proven through tens of millions of garments for more than 25 years. The FR portion of the fabric is a long-chain polymer engineered in situ and locked in the core of the cotton fiber, and the FR mechanism is solid-phase. These fabrics char instead of burning, just like most well known "inherent" fabrics.
Shifting Definitions over Time
Significant product characterization issues have recently emerged, as well. Some technologies that were clearly characterized by the market for decades as treated have suddenly been recast as "inherent." The definition has shifted over time to suit the convenience or commercial interests of the defining party. This process involves adding FR chemicals during fiber spinning to impart flame resistance to an otherwise flammable fiber; this was originally the precise definition of "treated" in the FR world. Yet in the past several years, a number of catalogs have relabeled fabrics containing these fibers as "inherent," apparently on the strength of the marketing advantage this characterization confers, while other sales literature continues to correctly label it "treated." To further confuse matters, one catalog from a major garment manufacturer lists some fabrics containing this fiber as inherent and others as treated!
Fabric Blends and Nomenclature
Most popular FR fabrics today are blends of different fibers, and this has created another whole level of misuse and misunderstanding. Independent of the issues discussed above around definitions and individual fiber technologies, what other fiber classes should be allowed, and what blend levels should be necessary to call a fabric "inherent"? Each of the following examples is currently being marketed as "inherent" by one or more major manufacturers:
- Should we call a blend of inherent and treated fibers inherent? If so, at what ratio of "inherent" to "treated"? Is 1 percent inherent enough, and, if not, what level is sufficient?
- What about a fabric that is about 15-20 percent inherent (by original definition), about 40-50 percent of a fiber that used to be called treated, but which has recently been re-labeled inherent, and about 30-40 percent Non-FR natural fibers?
- What should we call a fabric which in which half the blend is an FR fiber that was called treated for 20 years, but recently was relabeled as inherent ... and the other half of the fabric isn't inherent, isn't treated, and isn't even flame resistant? If it is half non-FR, how can it possibly be characterized as "inherent?"
Conclusion
The fabric properties most important to wearers of flame resistant apparel are protection, comfort, and overall value. There are large differences among otherwise compliant FR fabrics, including those that at first glance appear quite similar. Becausee the fabric brand is the largest factor in determining these core values, most programs specify the fabric first. Durability of these properties is critical; what ultimately matters most is that the apparel is FR for the life of the garment and market proven. The "Inherent" vs. "Treated" world view is simply inaccurate and/or actively misleading, both on the fiber level and as applied to fabric blends. This has been reaffirmed recently as the market has been flooded by new, unproven FR fabrics being marketed as "Inherent" and "Treated" (many of which are actually "Inherent-Treated" blends), which look good in the lab or in a trade show booth but simply do not perform in the real world.
There have been too many failures, including FR durability, excessive shrinkage, poor comfort, and more. The critical differentiator should be "Proven" vs. "Unproven," because when it comes safety, decisions should be made on facts, not stories and marketing terms.
Scott Margolin is International Technical Director for Westex.