Treated fabrics are cotton or cotton-blend fabrics that are treated with chemicals that form a permanent bond with the fabric that cannot be washed out when the recommended laundering instructions are followed. The chemical treatment changes the molecular structure of the fabric. Carhartt uses FR-treated cotton fabrics for most styles.

Inherent fabrics are made with fibers that are designed to be flame resistant. Flame resistance is part of the fibers' DNA and is a permanent characteristic of the fabric. Modacrylic blends are commonly used inherent fabrics. Carhartt uses this blend for our inherently flame-resistant styles.

Many people ask about arc ratings when flame-resistant clothing is layered. The total arc rating cannot be determined by adding the ratings of the two items. In most cases the total arc rating is higher than the number calculated by simply adding the arc ratings from the two items. Layered testing is the only way to conduct testing to determine the total arc rating for layered FR garments.

Carhartt has conducted layered testing for a variety of combinations, using some of our most popular FR clothing styles. The resulting layered arc rating of the various combinations are listed on the table below for your reference.

_{Testing conducted for Carhartt, Inc. by Kinectrics High Current Laboratory, Toronto, Ontario, Canada}

Carhartt FR clothing is clearly identified on the outside with a "Carhartt FR" label in place of the traditional Carhartt label. Additionally, all Carhartt FR clothes have external PPE CAT rating tags - making it easy for supervisors and safety officers to see if workers are in compliance with regulations (Not all FR clothing is so labeled). ATPV/EBT values are shown on inside labels. In addition, product hangtags also distinguish Carhartt FR clothing. Garments that meet UL Classification for NFPA 2112 have a label sewn inside.

If exposed to electric arc flashes or flash fires, clothing made from most untreated (e.g.,non-FR) fibers will continue to burn once ignited. In contrast, Carhartt FR clothing is specially designed to self-extinguish within two seconds after the source of ignition is removed - thereby limiting the worker's degree of burns, and body burn percentage. FR fabrics are not flame proof; however, they are specially designed to be flame-resistant.

No. Carhartt flame-resistant clothing is guaranteed to be flame-resistant for the useful life of the garment; regardless of the number of washings (servicings) in either the home or industrial laundering, provided the garment care instructions are followed.

Non-treated cotton and wool are flammable fibers. If exposed to electric arcs and flash fires, these materials will continue to burn causing possible severe injury and death.

Like ATPV, Energy of Breakopen Threshold (EBT) is a rating assigned to FRC indicating the level of protection provided. EBT is used when ATPV cannot be measured due to flame-resistant fabric breakopen. EBT is also measured in calories per centimeter squared (cal/cm2).

The American Society for Testing and Materials (ASTM) developed F1506, the Standard Performance Specification for Flame Resistant Textile Material for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards. This is a pass/fail standard that requires a sample of flame-resistant fabric to self extinguish with a <2 second afterflame and a <6" char length. The FR fabric must also stand up to these requirements after 25 washes/dry cleaning. All Carhartt flame-resistant garments meet the ASTM F1506 requirement.

The PPE Category protection level worn by an FR user should be determined by the user's employer. The employer must do a risk assessment for the user's job and inform them of the protection level needed. This should never be determined by the apparel manufacturer (Carhartt) or the retailer.

Carhartt flame-resistant clothing has not been tested to meet the requirements of NFPA 1977, The Standard for Protective Clothing and Equipment for Wildland Fire Fighting, therefore, Carhartt flame-resistant clothing is not recommended for this use.

Carhartt does not make any garments that are specifically designed to be worn while welding, or performing similar jobs that involve exposure to sparks and flames. Carhartt Flame-Resistant Clothing will protect better than 100% cotton or synthetic garments, because the FR fabric is self-extinguishing. However, flame-resistant clothing is susceptible to holes and fabric burns created by sparks and metal debris generated by activities such as welding.

Yes. Carhartt FR Clothing can be repaired, but repairs must be made with fabrics and sewing threads that have at minimum the same flame-resistant properties as the original garment.

None of the current regulations governing the use of FR clothing specifically require the use of FR thread for embroidery applications. However, Carhartt recommends the use of flame-resistant thread for embroidery or emblem attachments.