Flame-resistant PPE (Personal Protective Equipment) is the best line of defense in the electrical and power industry. The arc rating in the FR Outerwear distinguishes between an injury and fatal case during fire accidents and electrical hazards in sectors. Employers and factory owners should ensure their employees or workers wear flame-resistant and fire-resistant uniforms with the industry-standard arc rating and abide by OSHA regulations. The article highlights the fundamental understanding of arc-rating and its importance in flame-resistant garments for factory workers and employees in different sectors.
Table of Contents
What is Arc Rating in FR Garments?
Arc rating indicates the protective characteristics of workwear fabric and wearable materials for safeguarding employees and workers against electric hazards, fire, and heat. The arc rating of an outwear measures the absorbing energy before it seeps enough to cause second and third-degree burn injuries. The measurement of arc rating is done in calories/cm2.
NFPA and OSHA
NFPA (National Fire Protection Association) Standard 70E defines arc rating, and it was established at the request of OSHA regulations. It avoids workplace accidents, injuries, and fatalities due to electrical and fire hazards. According to OSHA regulations, using arc-rated FR outerwear or uniforms is compulsory in workplaces that engage fire, arc flash, thermal electricity, high temperature, and toxic chemicals.
Categories of Arc Rating
There are four categories of arc rating according to NFPA. PPE (Personal Protective Equipment) classification ranges from Category 1 to Category 4. For example, Category 1 PPE equipment, like goggles and face protectors, and PPE FR Outerwear should be arc-rated for a minimum of 4 calories/cm2. In addition, employees or workers working in the Category 4 environment demand PPE and equipment with an arc rating of a minimum of 40 calories/cm2. The PPE in Category 4 must include flash suit hoods.
How to Test Arch Flash Garments?
While exploring the arc rating on FR outerwear, one should check the ATPV (arc thermal performance value) mentioned on the fabric. The ATPV is measured in calories/cm2. The arc thermal performance value recognizes where 1.2 calories/cm2 of energy transfers through the flame-resistant fabric. In addition, it is the point at which one can expect second or third-degree burns. The calorie/cm2 rating of the fabric is influenced by two arc rating testing methods- open or box testing methods.
Open Arc Testing Method
The method assesses a fabric’s rating by presenting it open under controlled lab-based conditions. The outcomes are examined against second-degree burn possibilities by calculating the potential of burn injuries at different energy spots. It measures in calories/cm2 with a potential of second-degree burn injuries.
Box Arc Testing Method
The testing gets done on both finished FR outerwear and FR fabric. It simulates real-life maintenance or service situations by incorporating low-voltage systems like switchboards, distribution boards, and boxes.
Calculating Arc Flash Garments
There are different categories for calculating arc flash garments.
HRC 0
In this category, the protection begins from 0 calories/cm2 and includes workwear, heating protection, safety glasses, trousers, and long-sleeved T-shirts. The category doesn’t keep employees relatively safe from arc flash events.
ARC CAT 1
It includes a single protection PPE layer with an arc rating of 4 calories/cm2. The clothing and gear include FR shirts, trousers, leather gloves, face shields, and headgear.
ARC CAT 2
It consists of a similar type of clothing and protective gear like ARC CAT 1, except with an additional safety layer and an arc rating of 8 calories/cm2.
ARC CAT 3
The minimum arc rating in category 3 is 25 calories/cm2 with extra PPE such as hearing protection, eye protection, leather footwear, a hat, and a full flash suit with at least three protection layers.
ARC CAT 4
It is the highest protection category, featuring a 40 calories/cm2 arc rating, and they should wear above their cotton underwear and multilayer arc-rated flash suits.
Conclusion
The above analysis clearly explains that flame-resistant (FR) Outerwear must be arc-rated, abiding by the NFPA and OSHA regulations. Employers and owners ensure their employees and workers wear arc-rated FR garments wherever necessary. The arc rating of FR outerwear determines the protection and safety of the workers from arc flashes and electrical and fire hazards.
