Hazard Level Risk Ratings Explained
Hazard Risk Category Levels
The chart, based on specific job tasks, ranges from HRC 1 (which is low risk and allows for 100% treated cotton), up to HRC 4 (which is high risk and requires FR clothing with a minimum arc rating of 40). The HRC is used to determine the necessary arc rating of a garment worn during a given job task. Wearing multiple layers of clothing may be required to obtain the necessary rating required for your job. Only your employer can tell you the required level of protection required for your job.
NFPA® has identified four FR hazardous risk category levels, which are numbered by severity from 1 to 4. Hazard Risk Category is the level of arc flash protection clothing you must wear to protect against a minimum level of incident energy measured in calories per centimeter sqared.
Meaning, electrical equipment, depending upon the energy delivering capability, under fault conditions can cause an explosion, or arc fault of a certain level, again measured in calories per centimeter squared. That explosion can deliver a certain amount of heat to a certain distance. Each level, 0-4, is rated at a certain amount of flame resistance, again measured in cal/cm2.
|Hazard Risk Category||Clothing Descirption||Required Minimum Arc Rating of PPE Cal/cm2|
|Cat 1||FR shirt and FR pants or FR coveralls (1 layer)||4|
|Cat 2||Cotton underwear plus FR shirt and FR pants (1 or 2 layers)||8|
|Cat 3||Cotton underwear plus FR shirt and FR pants plus FR coveralls, or Cotton underwear plus two FR coveralls (2 or 3 layers)||25|
|Cat 4||Cotton underwear plus FR shirt and FR pants plus multilayer flash suit (3 or more layers)||40|
ARC Rating Explained
A value of the energy necessary to pass through any given fabric to cause with 50% probability a second or third degree burn. This value is measured in calories/cm². The necessary Arc Rating for an article of clothing is determined by a Hazard/Risk Assessment and the resulting HRC. Usually measured in terms of ATPV or EBT. Simple put the ARC rating determines the protective characteristics of the fabric. The higher the ARC rating value the greater the protection. When the product is sold to protect workers from arcing faults, clothing manufacturer are required in indicate the ARC rating.
The National Fire Protection Association, known as NFPA®, was established in 1896, it's mission is to reduce the worldwide burden of fire and other hazards on the quality of life by providing and advocating consensus codes and standards, research, training, and education. NFPA® is the world's leading advocate of fire prevention and an authoritative source on public safety, NFPA® develops, publishes, and disseminates more than 300 consensus codes and standards intended to minimize the possibility and effects of fire and other risks. For more info visit www.nfpa.org.
NFPA® 2112 Explained
NFPA® 2112 provides minimum performance criteria and sets clear guidelines for minimum design, performance, certification requirements and test methods for Flame Resistant garments for use in areas at risk from flash fires—such as those where flammable gases or vapors, or combustible dusts might be present. The standard calls for flash fire testing to be conducted at three seconds with a pass/fail rate of 50% total body burn under ASTM F1930 (Standard Test Method for Evaluation of Flame Resistant Clothing for Protection Against Flash Fire Simulations Using an Instrumented Manikin) testing protocols. Bulwark garments have been certified by Underwriters laboratories to the requirements of NFPA® 2112, Standard on Flame Resistant Garments for Protection of Industrial Personnel Against Flash Fire and Canadian General Standards Board (CGSB) Standard 155.20, Workwear for protection against Hydrocarbon Flash Fire. For more info visit www.nfpa.org.
NFPA® 2112 Compliant
Bulwark Products marked as NFPA® 2112 Compliant are Certified by Underwriters Laboratories (UL) or other independent third party laboratories to meet the requirements of NFPA® 2112 Standard on Flame Resistant Garments for Protection of Industrial Personnel Against Flash Fire, 2012 Edition.
NFPA® 70E - Basic Terms & Definitions
An explosive release of energy caused by an electrical arc. An arc flash results from either a phase to ground or a phase to phase fault caused by such occurrences as accidental contact with electrical systems, build up of conductive dust, corrosion, dropped tools, and improper work procedures. During an arc flash, the temperature can reach 35,000° Fahrenheit, and exposure to an arc flash can result in serious burn injury and death. Every year, more than 2,000 people are admitted to burn centers with severe arc-flash burns.
A value of the energy necessary to pass through any given fabric to cause with 50% probability a second or third degree burn. This value is measured in calories/cm². The necessary Arc Rating for an article of clothing is determined by a Hazard/Risk Assessment and the resulting HRC. Usually measured in terms of ATPV or EBT.
The energy required to raise one gram of water one degree Celsius at one atmosphere pressure. Second-degree burns occur at 1.2 calories per centimeter squared per second (cal/cm²).
A dangerous condition caused by the release of energy from an electric arc. <
Flash Hazard Analysis:
A study investigating the potential exposure to arc-flash energy that a worker faces while performing a specific job task. The data collected in a Flash Hazard Analysis is used for the purpose of injury prevention and the determination of safe work practices and the appropriated levels of FR clothing and PPE.
Flash Protection Boundary:
The distance from an exposed live part within which a person could receive a second-degree burn if an electrical arc were to occur.
FR (Flame Resistant):
FR refers to the ability of a material to self-extinguish upon the removal of an ignition source.
HRC (Hazard/Risk Category):
The five Hazard/Risk categories are specified by the chart listed in NFPA® 70E. The chart, based on specific job tasks, ranges from HRC 1 (which is low risk and allows for 100% treated cotton), up to HRC 4 (which is high risk and requires FR clothing with a minimum arc rating of 40). The HRC is used to determine the necessary arc rating of a garment worn during a given job task.
A work standard published by the National Fire Protection Association (NFPA®) that covers aspects of electrical safety in the workplace. It includes the recommendation that those who work with, on or around energized equipment use adequate protection, including FR clothing.