Flame Resistant vs. Flame or Fire Retardant
Resistant in this context is defined as a material that is inherently resistant to igniting/burning and does not melt or drip when exposed directly to extreme heat or fire.
Textiles that meet this description include: Modacrylic, Nomex®, and Indura® FR materials.
Retardant is defined as a material that has been chemically treated to self-extinguish when the ignition source is removed. Polyester is most commonly used material used in high visibility safety apparel. When exposed to fire or heat, polyester melts and drips as a molten polymer. Molten polyester could cause additional injury to a worker wearing a polyester chemically treated vest exposed to arc flash.
The main consequence of these differences is that “Retardant” or “Self Extinguishing” vests are not compliant with any of the flame resistant standards referenced by the ANSI/ISEA 107 Standard and are therefore not permitted.
Characteristics of Flame-Resistant Clothing
- Does not ignite, burn, melt or drip
- Maintains a barrier
- Insulates the wearer from heat
- Resists breaking open
- Reduces burn injury and increases chances of survival
An arc flash is the light and heat produced from an electrical arc supplied with sufficient electrical energy to cause substantial damage, harm, fire or injury.
With increased awareness of the dangers of arc flash, FR materials are tested for their ability to resist arc flash. The arc rating is the maximum incident energy resistance demonstrated by a material prior to break open (a hole in the material) or necessary to pass through and cause with 50% probability a second degree burn. Among the best fabrics for protection against electrical arc flash are the Modacrylic-cotton blends.
As defined in ASTM 1506-18, Arc rating is the value attributed to materials that describes their performance to exposure to an electrical arc discharge. The arc rating is expressed in cal/cm2 and is derived from the determined value of Arc Thermal Performance Value (APTV) or Energy Breakopen Threshold (EBT). A garment’s arc rating can be found on the interior garment label.
Some manufacturers incorporate an exterior label that indicates its corresponding Arc Flash PPE Category (formerly Hazard Risk Category (HRC) value), making a garment’s protective levels obvious at all times.
NFPA 70E®, titled Standard for Electrical Safety in the Workplace®, is a standard of the National Fire Protection Association (NFPA®).
The document covers electrical safety requirements for industrial personnel (for example: electricians, maintenance workers, operators).
NFPA 70E® was developed by NFPA® at the request of OSHA to “help companies and employees avoid workplace injuries and fatalities due to shock, electrocution, arc flash, and arc blast, and assists in complying with [sections of the standards] OSHA 1910… and OSHA 1926″
As the NFPA® website states, the standard “encompasses safety-related work practices, safety-related maintenance requirements, and safety requirements for special equipment. The Standard includes guidance for making hazard identification and risk assessments, selecting appropriate PPE (Personal Protective Equipment), establishing an electrically safe work condition, and employee training.”
This comprehensive standard is available from NFPA.org http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70E.
High-Viz under NFPA 70E®
NFPA 70E® covers many different subjects. Our focus here is the integration of NFPA 70E® into the ANSI/ISEA 107 standard as follows:
- Meet a minimum ATPV (Arc Thermal Performance Value) rating in accordance with the PPE Category (CAT level) required for the job.
- Retain a minimum ATPV rating after laundering, for the life of the garment.
- Meet ASTM F1506
- Zippers must be flame resistant when used.
- Must have a tracking ID number
- Must show the garments ATPV rating
- Must indicate it meets ASTM F1506-18
- Shows Manufacturer, Size and Care instructions
Arc Thermal Performance Value (ATPV)
ATPV stands for Arc Thermal Performance Value, which is a value attributed to materials that describes their performance to exposure to an electrical arc discharge expressed in cal/cm2. The higher the ATPV Value, the more protection against electrical arc flash. The same applies to the PPE Category for FR clothing.