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- Flame Resistant FAQS
Flame Resistant FAQS
1. Is there a need for flame resistant work apparel?
All fabrics made of untreated natural fibres and most synthetic fibres are combustible. It is normal and expected that they will ignite and continue to burn when exposed to an ignition source such as flame or electric arc. Because clothing constructed from these normal fabrics meets flammability requirements established by 16 CFR Part 1610, it is generally accepted as having no unusual burning characteristics.
Resistance to ignition and burning is an abnormal condition of wearing apparel. When work environments or occupations pose a risk of garment ignition and burning, flame-resistant apparel should be considered and selected.
2. How do normal fabrics react to ignition?
Normal fabrics and apparel will burn away from the point of ignition with an increasing rate of flame spread and continue to burn after removal of the ignition source. Normal fabrics will continue to burn until they are extinguished or all flammable material is consumed.
3. How do flame resistant fabrics react to ignition?
Flame resistant fabrics and apparel are intended to resist ignition, prevent the spread of flames away from the immediate area of high heat impingement, and to self-extinguish almost immediately upon removal of the ignition source.
4. Does flame resistant apparel prevent burn injury?
Flame resistant apparel will not provide significant protection from burn injury in the immediate area of contact with the ignition source. However, flame-resistant garments do provide protection against clothing ignition and sustained flame spread.
5. What type of undergarments should be worn?
National Fire Protection Association (NFPA) 70E Standard for Electrical Safety in the Workplace, states that non-melting, flammable fibre undergarments may be used in conjunction with flame resistant apparel. Flame resistant t-shirts, Henleys and base layer garments can provide additional wearer protection.
6. Is flame resistant apparel still effective if contaminated with flammable substances?
Flammable substances on flame resistant apparel will ignite and continue to burn on the surface of the flame resistant garment. Flame resistant apparel should be immediately removed and replaced with clean flame resistant apparel if they become fouled with flammable material. If laundering or dry cleaning cannot remove flammable contaminants, the contaminated garments should be removed from service.
7. Is 100% cotton fabric "flame resistant"?
There is a common perception that untreated 100% cotton fabric is somehow "flame resistant." This is simply not true. While heavyweight untreated 100% cotton fabrics may be more difficult to ignite, they can and will ignite and continue to burn if exposed to an ignition source.
8. What are some common causes of ignition and burning of work apparel?
- Ignition of flammable liquids and/or other flammable soils on the garment.
- Contact with, or close proximity to, molten metals.
- Contact with sparks and slag from flame cutting or welding.
- Contact with open flames.
- High energy electrical discharges or other electric arc events.
- Explosion of vapors from volatile liquids or from flammable gases.
- Ignition of combustible dusts.
Where any risk of ignition exists in the workplace, there is a need for flame resistant apparel.
9. What is the employer's responsibility?
Under paragraph 5a1, the General Duty Clause of the federal OSHA Act, it is the employer's responsibility to identify risks and hazards in the workplace and seek out appropriate protective work apparel and equipment for the protection of workers.
In making this hazard assessment, the employer must consider the risks present and the most appropriate means of addressing those risks. Where ignition risks are present, flame resistant protective apparel can become a prudent part of an action plan to address these concerns.
10. How do I choose the correct flame resistant apparel?
Any flame and thermal protective fabric must provide the wearer with the expected degree of protection for the useful life of the garment. Apparel is specified based on the employer's evaluation of workplace hazards. Protective garments, which function as wearing apparel for normal work activities, must be comfortable and durable while achieving appearance that is acceptable to both the employer and the wearer. In addition to these general considerations, there may be other hazards present such as chemical or molten substance exposure. Finally, these multi-use garments must be able to withstand laundering to remove soils and flammable contaminants and be returned to service without excessive colour loss, fuzzing/pilling (surface appearance change) or excessive shrinkage.
Questions About NFPA 70E:
1. What is NFPA 70E and why is compliance with this standard so important?
The National Fire Protection Association 70E Standard is a comprehensive standard that contains detailed instructions on how to protect workers from the heat of electric arc exposures.
2. Who is covered under NFPA 70E?
Employees during activities such as operation, maintenance and demolition of exposed energized electrical conductors or circuit parts. Research shows that approximately 10% of the employees in any operation work as electricians, maintenance, or other categories of work covered by this standard.
3. What job tasks are not covered under NFPA 70E?
Examples of job tasks not covered under the 2000 Edition of NFPA 70E include installations that occur:
- In ships, watercraft, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and RVs
- In underground mines
- On railways used exclusively for the operation of rolling stock
- On communication equipment under exclusive control of communication utilities
- Under the exclusive control of electric utilities for generation, transmission and distribution
4. Are electric utilities covered under NFPA 70E?
No. Currently, NFPA 70E guidelines do not cover the generation, transmission and distribution areas of electrical utilities.
5. Does OSHA enforce NFPA 70E?
OSHA believes that the NFPA 70E standard offers useful guidance for employers and employees attempting to control electrical hazards, but OSHA has not conducted a rulemaking and therefore does not "enforce" NFPA 70E. OSHA does use consensus standards, such as NFPA 70 as evidence of hazard recognition in evaluating General Duty Clause violations.
6. Where can I get a copy of NFPA 70E?
NFPA 70E is available from NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9109; phone: 1-800-344-3555; online at: http://catalog.nfpa.org.
7. What is ATPV EBT?
The standard requires that arc rated garments have a minimum Arc Thermal Performance Value (ATPV) based on the hazard/risk analysis for the task being performed. The ATPV is expressed in calories per square centimeter and represents the protection from electric arcs provided by the garment. If the ATPV cannot be calculated because the fabric breaks open, the energy causing the break open in expressed as the Breakopen Threshold Energy (EBT).
8. Where do I find arc ratings?
Arc ratings are included on Canadian Linen flame resistant garment labels and in Canadian Linen flame resistant apparel brochures.
9. Is there apparel that offers a higher level of protection than is available from single layer garments?
Electrical switching clothing (flash suits) is available for those needing HRC 3 (25 minimum ATPV) or HRC 4 (40 minimum ATPV). Many insulated outerwear garments also have ATPVs greater than 25. These can be used for specific applications where higher arc ratings are needed. Keep in mind that hearing, head, face and neck protection are also required for these higher exposure levels.
10. How do I do calculations in NFPA 70E?
Arc rated clothing and personal protective equipment (PPE) must be worn either based on the calculated incident energy determined for the specific task or by using Table 130(C)(9) to determine the hazard/risk category (HRC). HRC is specified based on specific job tasks. These range from HRC 0 that allows non-melting flammable materials up to HRC 4 that requires an arc rated flame resistant shirt and pants or flame resistant coverall, and arc flash suit with a minimum system arc rating of 40.
Annex H provides a simplified approach to selecting appropriate arc rated clothing and PPE based on whether the ask requires "everyday work clothing" or "electrical switching clothing."
11. Can those covered by this standard just wear heavyweight non-melting flammable garments such as denim jeans?
Probably not. Non-melting flammable garments are only allowed for HRC 0 exposures. Employees must wear flame resistant apparel wherever there is a possible exposure to an electric arc flash above the threshold incident-energy level for a second-degree burn (1.2 cal/cm2).
12. Can workers continue to wear flammable T-shirts under their arc rated garments?
Layers of non-melting flammable garments are permissible to be worn under flame resistant apparel for added protection. However, if Table 120.7(C)(9) is used to determine the HRC, only flame resistant layers within the layered system are used to determine system arc rating. Arc Ratings of individual layers cannot simply be added together. Any garment worn as the outer layer, including rainwear, must be flame resistant.
Questions About Fabrics/Apparel:
1. What is the difference between "inherent" and "treated" flame resistant apparel?
Both deliver protection. It is the responsibility of the employer to determine the appropriate selection for each environment.
In inherently flame resistant fabrics, flame resistance is an essential characteristic of the fibre from the textile is made. Because the actual structure of the fibre itself is not flammable, the protection it affords is permanent-it can never be worn away or washed out. When exposed to flame, inherently flame resistant fibre swells and becomes thicker, forming protective barrier between the heat source and the skin. This protective barrier stays supple until it cools, giving the wearer vital extra seconds of protection to escape.
Treated fabrics are treated with a flame retardant chemical to make them flame resistant. The fibres used in these fabrics, such as cotton, are not normally considered protective and become flame resistant because of the treatment. The durability of the treatment can vary from very limited life to the life of the garment. Unlike fabrics made with inherently flame resistant fibres, chemically treated flame resistant fabrics may have their flame resistant properties diminished or removed completely depending on how these fabrics are laundered and/or which chemicals they are exposed to in the work environment.
However, fabrics made from treated synthetic fibres-which are extruded with a flame retardant chemical in the fibre-forming process-become flame resistant for the life of the garment because the flame retardant cannot be removed by wear of laundering.
2. What is Nomex® IIIA?
Nomex® IIIA by DuPont is an inherently flame resistant fabric and provides excellent protection from fire and arc flash hazards. A blend of 93% Nomex®, 5% Kevlar® and 2% static dissipative fibre is woven into fabric to create flame resistant protection for industrial workers in Flash Fire (NFPA 2112) and HRC 1 Arc Flash applications.
Nomex® IIIA minimizes break open and maintains a stable, inert barrier between the fire and skin, protecting the wearer from direct exposure. Forming a tough, protective char when exposed to flame, the fabric stays supple until it cools, allowing wearers the valuable seconds they need to escape fires. The lightweight, durable fabric resists abrasion, tears and chemicals, lasting three to five times longer than other standard and protective fibres.
3. What is INDURA® Ultra Soft®?
INDURA® Ultra Soft®, a chemically treated fabric comprised of 88% cotton and 12% high tenacity nylon blend, is guaranteed flame-resistant for the life of the garment. The high tenacity nylon is focused on the face of the fabric, substantially improving abrasion resistance, as well as extending garment wear life by over 50 percent. Featuring multi-purpose protection, INDURA® Ultra Soft® provides superior protection in Electrical Arc Exposure, NFPA 2112 Flash Fire Testing and in welding and ferrous metal applications. The soft, yet breathable, fabric stays cool in the summer and warm in the winter, providing worker comfort in any condition.
4. What is EXCEL FR®?
Combining comfort and protection, EXCEL FR® treated fabric is 100% flame-resistant and 100% cotton. EXCEL FR® cotton garments offer unbeatable protection for foundries, flame cutting and welding, as well as electrical utilities and the chemical, oil, gas and petrochemical industries.
EXCEL FR® fabric is treated with a flame retardant chemical in the fibre-forming process. This procedure ensures the fabric's flame-resistant properties are not compromised by laundering or by chemical exposure in the work environment. With this treatment process, all EXCEL FR® cotton apparel is guaranteed flame-resistant for the life of the garment.
EXCEL FR delivers good resistance to dry heat and acts as a natural insulator. Additionally, moisture regain of durable FR cotton is excellent, resulting in low static propensity.
5. What is COOL TOUCH® 2?
COOL TOUCH® 2 is an inherently flame-resistant fibre blend of 48% Modacrylic, 37% Lyocell, and 15% para aramid fibre. Providing flame-resistant protection, high durability and comfort, COOL TOUCH® 2 offers the ultimate protection in a lightweight, wearable fabric. The fabric is designed to provide protection in NFPA 70E/Arc Flash HRC 2 applications and Flash Fire (NFPA 2112) applications.
COOL TOUCH® 2 fabric resists abrasion and delivers high strength with low thermal shrinkage. Because COOL TOUCH® 2 garments are made from a blend of inherently IR fibres, the fabric's flame-resistant property cannot be removed by wear or laundering.
6. Why is "inherent" protection important to me?
The flame resistant properties of inherent fabrics cannot be washed out or worn away, period. This means the flame resistant properties of apparel made of inherent fibres cannot be compromised. It is crucial for the wearer to know the flame resistant protection is always there.
7. What does "inherent for the life of the garment" mean?
Only garments using fabrics made of inherently flame-resistant fibres are truly "inherent."
8. Can flame resistant properties be removed from a garment?
For flame resistant treated fabric, such as flame resistant cotton/nylon blends, one way to remove its flame resistant properties is to use regular chlorine bleach while washing the garment. While use of chlorine bleach may not be recommended per some fabric manufacturers' laundry instructions, this can happen in the real world. It does not take many washes with chlorine bleach to damage the flame resistant properties of a flame resistant cotton or cotton/nylon fabric. And unfortunately, the wearer would not be able to tell it was no longer flame resistant simply by looking at the garment. With inherent fabrics, the flame resistant properties cannot be removed.
9. What will happen if I home launder flame resistant treated cotton/nylon or Nomex® IIIA garments?
If home laundering instructions for Nomex® IIIA and flame resistant treated cotton/nylon garments are followed precisely, nothing negative should happen to any of these garments. However, there have been specific instances when flame resistant treated cotton/nylon garments were laundered using hydrogen peroxide (a type of oxygen bleach) during the wash cycle and the flame resistant properties of the flame resistant cotton/nylon fabrics were compromised.
10. Other than chlorine bleach, what else could damage the flame resistant properties of flame resistant treated garments?
The combination of hydrogen peroxide (a type of oxygen bleach) with 'hard' water during laundering could compromise the flame resistant properties of garments made with flame resistant treated fabrics. Exposure to oxidizing (e.g., chlorine-containing) chemicals in the workplace may, over time, compromise the flame-resistant properties of garments made with flame resistant treated fabrics.
11. How will I know if the flame resistant treated garment's flame resistant properties have been compromised?
Without performing destructive testing, such as vertical flammability testing, you would not know. This is dangerous, since the wearer cannot see the difference between a flame resistant treated garment that is still effective and one that has lost its flame resistant properties.
12. When should I "retire" my flame resistant apparel from service?
Any garment with visible holes, rips, and/or tears or contamination from flammable materials should be properly repaired, cleaned, or removed from service. But it is difficult to judge the remaining level of flame-resistance in a flame resistant treated garment because there are no visible cues. The flame resistant performance can only be determined through a destructive test. Since the flame resistant properties of a truly inherent flame resistant fabric, like Nomex® IIIA, do not change with use or laundering, the flame resistant properties for Nomex® IIIA will be there no matter the garment age or how it was laundered.
A garment made with flame resistant treated fabric, such as flame resistant cotton/nylon blends, may need to be retired from service because its flame resistant chemical treatment was compromised, long before the fabric shows any visible wear. However, the wearer would not know this since the garment would show no indication of this compromise.
13. If inherent flame resistant apparel and flame resistant treated garments perform differently, how can they both be certified to the same standard?
The two main garment performance standards for flame resistant apparel, NFPA 2112 and ASTM F1506 (used for NFPA 70E), only specify minimum performance levels for fabrics and garments. These standards do not address all factors related to durability of the flame resistant properties. It is the end-user's responsibility to determine if these minimum standards provide an appropriate performance level for their particular application.
14. If Nomex® IIIA fabrics are inherently flame resistant, why do the DuPont laundry instructions advise me not to use chlorine bleach?
Repeated use of chlorine bleach in the laundry can affect fabric colour and can weaken fabric strength, which may shorten the useful wear life of the garment. Exposure to chlorine bleach will not affect the flame-resistant properties of inherently flame resistant fabrics like Nomex® IIIA.
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