How Does Arc Rated Clothing Help Protect Workers from Arc Flash Hazards?
Key Takeaways:
- Arc rated clothing helps resist ignition, continued burning and thermal energy transfer
- An arc rating shows that a garment or clothing system has been evaluated for electric-arc exposure
- All arc rated clothing is flame resistant, but not all flame-resistant clothing is arc rated
- Effective protection depends on matching the clothing and complete PPE system to the assessed hazard
- Proper fit, use, care and replacement help preserve protection throughout the garment’s service life
Arc rated (AR) clothing helps protect workers by resisting ignition and limiting the transfer of thermal energy during an arc flash. It can also help prevent clothing from continuing to burn after the initial exposure.
For safety leaders, choosing protective workwear takes more than checking for an AR label. You need to know how the clothing protects workers, what its arc rating means and which workers need it based on the hazards in your workplace.
What happens to clothing during an arc flash?
An arc flash can expose a worker to intense heat, molten metal and rapidly released energy. Ordinary workwear may ignite during the event and continue burning after the initial exposure ends. The Occupational Safety and Health Administration (OSHA) reports that most arc flash burn injuries occur when an arc ignites flammable clothing rather than from the arc itself.
That creates a serious clothing-selection risk. A garment that looks durable enough for industrial work may add to an injury if its materials ignite, melt or continue burning.
An arc flash may also send heat or molten material through seams, closures and other openings. What a worker wears underneath the protective clothing can therefore affect the overall exposure. The complete clothing system matters, including underlayers and outerwear.
How does arc rated clothing work?
Arc rated clothing is flame-resistant workwear that has been evaluated for exposure to electric-arc energy. Its protection comes from the performance of its materials, construction and complete garment design.
- Resists ignition and continued burning
When ordinary clothing ignites, the material itself can become an additional source of heat. Arc rated clothing is designed to resist ignition and stop burning after the exposure ends.
- Helps limit thermal energy transfer
AR clothing helps create a barrier between the arc’s thermal energy and the wearer. The garment’s materials and construction influence how much energy reaches the worker.
- Provides a rating that can be matched to the hazard
Arc ratings are measured in calories per square centimeter (cal/cm²). This unit describes thermal energy exposure and provides a way to compare the assessed incident energy with the protection a garment supports.
What is the difference between arc rated and flame-resistant clothing?
All arc rated clothing is flame resistant, but not all flame-resistant clothing (FRC) is arc rated.
This distinction matters when workers perform tasks near energized electrical equipment. OSHA cautions that flame-resistant or rubber-insulated PPE does not necessarily provide arc-flash protection.
When reviewing a garment, check its arc rating, performance standards, care instructions and condition. Avoid relying on a general AR/FR designation or product claim alone.
What does an arc rating tell a safety leader?
An arc rating identifies the level of electric-arc exposure at which a material or material system was evaluated under controlled test conditions. It helps safety leaders connect clothing selection to the exposure identified through a hazard assessment.
| Arc-Rating Terms to Know | |
|---|---|
| ATPV | Arc Thermal Performance Value |
| EBT | Energy Breakopen Threshold |
| cal/cm2 | The unit used to express incident energy and an arc rating |
Why AR clothing is part of a complete PPE system
Depending on the task and exposure, one AR garment may be insufficient for the risks and hazards workers face on the job. That’s why many safety managers approach workwear as a complete system, rather than a single line item.
A complete system may include:
- AR shirts, pants or coveralls
- AR outerwear
- A face shield, balaclava or arc-flash suit hood
- Eye and hearing protection
- Hand protection
- Suitable footwear
- Appropriate underlayers
Layering arc rated clothing can provide protection that one garment alone cannot. When calculating the arc-rating of a complete system, safety leaders should not just add separate garment ratings together unless the manufacturer provides a tested system rating.
What can undermine arc rated clothing protection?
Selecting appropriately rated clothing is only the first step. How garments are worn, inspected, cared for and replaced can also affect their protective performance.
Common problems include:
- Rolling sleeves or leaving closures open
- Wearing unsuitable underlays or outerwear
- Using garments with holes, tears or damaged fasteners
- Making repairs with unapproved materials
- Laundering methods that do not adhere to manufacturer care instructions
- Wearing a garment with missing or unreadable labels
Workers should know how to inspect their apparel before use and when to remove an item from service. Safety leaders should also have a process for replacing damaged or worn-out garments in a timely manner.
How to manage and maintain AR clothing for work
Daily execution is where a technically correct selection can become difficult to sustain. Workers change roles, garments need repair and replacement items must be available when needed.
An AR workwear program should support:
- Consistent garment availability
- Inspection for damage or contamination
- Care that follows manufacturer instructions
- Repairs made with appropriate materials
- Timely removal and replacement of unsuitable garments
- Worker training and feedback
- Reassessment when workplace conditions change
A managed AR/FR workwear program can help standardize laundering, inspection, repair, replacement and garment availability after the employer determines the required protection. This operational support can reduce the internal workload involved in maintaining AR workwear consistently.
Learn more about electrical safety and AR workwear
Visit the Cintas Electrical Safety Resource Center to explore educational information about arc-flash hazards, protective workwear, assessments and training.
Frequently Asked Questions
What is arc rated clothing?
Arc rated (AR) clothing is flame-resistant workwear that has been evaluated for electric-arc exposure and assigned an arc rating. The rating helps employers select clothing for the exposure identified through a hazard assessment.
How does arc rated clothing protect a worker?
AR clothing helps resist ignition, stop continued burning and limit the transfer of thermal energy to the wearer. It is designed to reduce potential injury severity, but it cannot eliminate the hazard or guarantee that a worker will avoid injury.
Is FR the same as AR clothing?
No. All arc rated clothing is flame resistant, but not all flame-resistant clothing is arc rated. AR clothing has also been evaluated for electric-arc exposure and carries an arc rating.
What does cal/cm² mean on AR clothing?
Calories per square centimeter, written as cal/cm², is a unit used to express thermal energy. It appears in incident-energy calculations and arc ratings so employers can compare an assessed exposure with the tested rating of protective clothing.
Can workers wear regular clothing underneath AR clothing?
Underlayers can affect the protective system because heat or molten material may enter through seams, closures or openings. Employers should evaluate arc rated base layers as part of PPE selection and follow current standards, manufacturer instructions and qualified safety guidance.