FR Work Wear Guide


The Meaning of FR

General Understandings

Terms such as ‘flame resistant’, ‘flame retardant’ or 'fire resistant’ are synonymous with what are commonly known as FR fabrics, FR materials or FR protective clothing. In general, the meaning of flame resistant and more specifically, inherently flame resistant (IFR) is, "garments manufactured from textiles with fibres with a chemical structure that will not burn in air; that is, they do not promote burning after exposure to and removal from the source of ignition. Flame retardant treatment fabric (FRT) is cotton or a cotton/nylon blend made flame resistant through a chemical treatment applied to the fabric/fibre". Flame resistant fabrics and garments are engineered to resist ignition, prevent the spread of flames away from the immediate area of high impingement and to self-extinguish almost immediately upon removal of the ignition source. Normal work apparel will ignite and continue to burn if exposed to an ignition source such as flame or electric arc. Everyday fabrics will continue to burn until they are extinguished or all flammable material is consumed.

When discussing inherent flame resistance, a fabric is categorised as IFR if it is woven from fibres that yield a product that meets flame and heat standards without being subject to any processing or addition of chemicals. IFR fabrics are expected to remain flame retardant for their lifetime, even after repeated washings. The word 'inherent', together with the adverb 'inherently', is defined by the Oxford English Dictionary as an adjective which describes "existing in something as a permanent, essential or characteristic attribute".

Fabrics - 'Inherent' versus 'Treated'

There is continual debate in the FR fabric industry about the merits of 'inherent' versus 'treated' fabrics. During recent years the topic has become increasingly subjective mainly because of the influx of many new so-called FR fabrics. The above section briefly discusses what are commonly referred to distinctions; distinctions now entrenched in marketplace understanding and literature. However, it is important that Corporations not only be aware of the differences between fabric types but also how these differences impact performance. 'Inherent' and 'treated' fabrics are engineered to promote charring rather than burning and today's well-known 'treated' brands are capable of performing just as well as the well-known 'inherent' brands.

Two very important considerations must be taken into account when considering this topic;

At this point readers should perhaps determine their own conclusion by referring to the article published by Westex Corporation titled "The Truth About Flame Resistant Fabric Terms: What's Really Behind the "Inherent" versus "Treated" Debate". The article highlights the misunderstandings and inaccuracies surrounding this widely debated topic.

Non-FR Fabrics

When regular or non-FR cotton or cotton/polyester work clothing contacts a flame or intense heat source, it will ignite and continue to burn or smoulder until aggressively extinguished. Fabrics which do not have FR properties may further compound burns or injury by melting into the skin, or in worse case, cause death. FR textiles will not support combustion and will self-extinguish once the initial heat source has been removed. The potential for burn injuries will be contained to the ignition or exposure contact area and those areas not covered by the FR clothing. For example, where there is risk of electric arc, everyday work wear manufactured from regular cotton or cotton/polyester fabrics can be readily ignited at exposure levels as low as 4 to 5 cal/cm2 and once ignited will continue to burn adding to the extent of injury sustained from the arc alone. Second-degree burns occur at 1.2 cal/cm2.

Primary and Secondary Personal Protective Clothing (PPC)

Today's generation of FR textiles are engineered to provide workers with extra seconds to escape life threatening situations. The level of protection provided by FR Personal Protective Clothing is classed as either Primary or Secondary.

 

 Primary Protective Apparel

Fire Fighters Iron Casting

 

Primary protection apparel is often referred to as ‘front line’ or ‘first line’ protection and can be likened to turnout gear worn by structural fire fighters. When there is significant exposure, primary protective items are worn over secondary protective clothing and removed when primary protection is no longer required. Primary protective items include full length smelter aprons and coats, aluminised suits, leg, shoulder and arm spats, switching coats, hoods and pants, insulating rubber gloves and leather protectors, head protection, face shields and fire brigade turnout gear.

 

Secondary Protective Apparel

Refinery Engineerselectric utility lineman

Secondary protection apparel is designed for continuous wear in designated locations where intermittent exposure to electric arc, molten substance splash, radiant heat and flame is possible (as defined by ASTM Standard F1002). Often referred to as ‘uniform clothing’ and worn on a daily basis, it is the key component of FR work wear and is designed for continual wear in the workplace. Secondary protective clothing includes shirts, trousers, pullovers, jackets, socks and coveralls/overalls.

 

FR Undergarments

These garments provide an additional layer and create an air gap between the undergarments and the secondary protective layer. Undergarments can enhance wearer comfort by overcoming textile stiffness and in some cases assist with allergies resulting from the use of certain types of textiles. For environments with electric arc hazards, the use of FR undergarments as a multi-layer system will significantly increase Arc Thermal Performance Value (ATPV). It should be noted that non-flame resistant 100% cotton will ignite just as easily as poly/cotton fabric in an electric arc flash. While 100% cotton will not melt or drip, it burns hotter than poly/cotton fabrics and typically is heavier, allowing it to burn longer and making it harder to extinguish.


Workplace Hazards

Generally, no one workplace is the same and consequently before finalising FR work wear programs, end users should determine a fabric’s suitability in accordance with the relevant OH&S legislation and their own workplace conditions. Testing to international standards is normally conducted under laboratory conditions and can vary from actual workplace conditions. Test criteria and results should only be used as a guide when conducting in-house risk assessments. To ensure proper protection, corporations should perform their own hazard risk analysis and install FR work wear programs based on the probable worst case exposure for a workplace task.

The primary aluminium industry is an example where secondary protective work wear must be capable of providing protection against a wide range of exposures. Workers in primary smelting areas must contend not only with molten aluminium and molten cryolite, but also electric arc. Re-melt and cast house workers must contend with molten metal splash and radiant heat. Electrical and maintenance workers are constantly faced with electric arc hazards. Many of the new generation fabrics are able to cope with such a diverse range of exposures and most are inherently FR, lightweight, highly breathable and offer maximum protection with superior comfort.

The criteria used in defining FR protective work wear is "any clothing worn by workers as protection within their working environment". The most common industrial hazards which FR work wear must protect against include:

In many situations, several potential hazards may overlap. For instance, fire and extremes of heat, acid and contaminants, temperature and altitude. Where this potential is likely, textiles used for protective clothing may be required to provide simultaneous protection against several potential hazards. This duality of function leads to other criteria that need to be considered and include:


Selection Criteria

A number of factors need to be considered when assessing FR work wear programs:


Safety and Comfort

When finalising PPC programs, corporations must decide the two conflicting issues of safety versus comfort (here textile experts are speaking about "the double edged sword"). While the level of protection typically rests in a textile's weight and composition, the issues of radiant and convective heat are often underestimated: clothing needs to protect against the heat from outside but allow the body-heat to escape. A bulky and heavy garment will temporarily provide good protection against radiant and convective heat, but the worker will soon collapse, because the body's heat will become trapped inside. This can lead to muscle cramps, dehydration, fatigue, heat stress and in the worst case, heat stroke. 

The protection provided by FR textiles is usually measured quantitatively, that is, the rate at which heat is transferred through the fabric and qualitatively, that is, whether there is any subsequent textile destruction (break-open), shrinkage, ignition or adhesion of metal to the textile.

Often workers will be subjected to high ambient temperatures, humid conditions, hard physical work and high levels of radiant heat exposure. FR textiles which dissipate the body’s heat and moisture quickly and efficiently are regarded as being the most ‘comfortable’, which in general terms means softness, smoothness and breathability.

ArcFlashWear’s textiles have the ability to absorb moisture and create an evaporative cooling effect. This feature is commonly known as a ‘wicking effect’ (moisture transfer) which limits heat stress, keeping workers cool and comfortable. Wool, for example, is one of the oldest known natural fibres and is constantly in demand for its unique natural properties including comfort and inherent fire resistance, properties that science cannot yet replicate. The ability of Wool to absorb up to 30 percent of its weight in moisture vapour gives it superior comfort, insulation, anti-static properties and flame resistance. While Wool can absorb moisture, it also repels liquids. Wool has a natural elasticity greater than any other natural fibre, which makes it comfortable to wear as it fits the shape of the body.

Heat Stress and Heat Stroke

Mental and physical exertion increases the body's core temperature. Increased blood circulation and the production of perspiration cool the body down. This cooling down process can be disrupted due to improper textile heat and moisture management leading to problems with concentration, fatigue, muscle cramps, difficulties breathing and ultimately heat stroke. The excellent moisture management and breathability of FR fibres such as Lenzing FR®, Nomex®, Cotton, Kermel® and Wool, used in the manufacturing of premium FR work wear, lead to a reduction in the risk from this mortal danger.


Construction

FR work wear should be designed and manufactured to protect against the probable worst case exposure for a workplace task while offering a number of important features.


Care and Maintenance

Correct cleaning and maintenance of FR work wear will ensure it provides continual safety, comfort, serviceability and longevity. Premium textiles and materials carry premium prices. Consequently, corporations have a significant investment in their FR work wear programs, which like any other asset must be effectively managed.

Issues to be considered when discussing care and maintenance include: