Electrical and Arc Flash Safety

Perhaps the most significant change to the 2009 NFPA 70E is a redefinition of PPE hazard risk categories (HRCs). The principles determining a PPE system for each hazard risk level are now based on developing a clothing system meeting a specific tested cal/cm2 level and comprised completely of arc-rated materials.

The key to this approach is wearing the correct amount of arc-rated protection, not necessarily the exact pieces of clothing listed in the 70E tables. For example, if eight cal/cm2 of protection are required, you can wear an eight cal/cm² arc-rated shirt and pants, or a four cal/cm² arc-rated shirt and pants and a four cal/cm² arc-rated coverall; or an eight cal/cm² arc-rated coverall over cotton shirt and pants. See what we mean? It is the total level of arc-rated protection that matters – that and the absence of synthetic materials. You can wear one level of eight calories or two layers of four calories, or any combination equaling the total cal/cm2 necessary to protect you from severe burns if an arc flash occurs. This method applies to all hazard risk categories. The 25 cal/cm2 required for HRC 3 protection can be achieved by wearing a shirt and pants, coveralls, arc flash suit, or any combination of clothing that meets the required protection level. This change gives employers more leeway in developing a protective clothing system that meets the specific needs of their companies.

If you look at the requirements for HRC 2 in Table 130.7(C) (10), you see the following under clothing requirements:

FR Clothing, Minimum Arc Rating of 8

Arc-rated long-sleeve shirt

Arc-rated pants

Arc-rated coverall

Arc-rated face shield or arc flash suit hood

Arc-rated jacket, parka, or rainwear (as needed) *

Previously the standard required HRC 2 to include an eight cal/cm² shirt or an eight cal/cm² coverall or a 4 cal/cm² with a cotton t-shirt. The cotton t-shirt was mandated. Now, you choose any eight cal/cm² system be it one layer or more but the cotton t-shirt is no longer mandatory and unrated layers do not add to the protection levels in the HRC´s. Natural fiber clothing like cotton, wool and silk are still allowed but cannot add to the protection level because of the risk of ignition. If a company wants to use cotton for protection, they must rate the system with the cotton underneath and control the cotton layer to assure no ignition. This can be done using the ASTM F1959 arc test method.

While this new approach offers more options in choosing PPE clothing, a company cannot randomly choose, for example, a four cal/cm² arc-rated shirt and a four cal/cm² arc-rated t-shirt, deem it an eight cal/cm² system and issue the clothing to electrical workers. When layers are used, the total system must be tested to get the total arc rating. Why? Because the sum does not always equal the whole. Most often, testing proves the system provides greater protection than the sum of its individual parts. However, the opposite may hold true. Some systems protect better than others. Some are barely additive (i.e. 4 cal/cm² + 4 cal/cm² = 8 cal/cm² ) but other systems such as using a heavy layer over a light layer might allow second degree burns at little more than the outer layer´s protective level (i.e. 4 cal/cm² + 8 cal/cm² = 8.1 cal/cm²) but most systems multiply the protection (i.e. 4 cal/cm² + 4 cal/cm² = 20 cal/cm²) See NFPA 70E Standard for Electrical Safety in the Workplace, 2009 Edition, M.3-3.1.

If you want to use an HRC system of layers, you will find many of the larger clothing manufacturers have already tested their arc-rated clothing as a system. Some mixed systems have been tested by utilities and this data is available free of charge from ArcWear.com at ArcWear.com/arctest.

*Additional PPE equipment is also required, such as hard hat and safety glasses, but left out of this list since we are only focusing on clothing.

By Vickie Frost, Hugh Hoagland & Bill Shinn

Vickie, Hugh and Bill are Sr. Partners in eHazard the leading electrical safety and arc flash training company.

Vickie Frost is a technical writer and has been involved in electrical safety for over 20 years.

Hugh Hoagland & Bill Shinn, are members of ASTM F18 and Hugh is taskforce chair of many arc test methods. Bill has over 40 years electrical safety experience and is a Professional Electrical Engineer, retired from Alcoa.

Hugh does most of the world´s electric arc flash testing on clothing and PPE and does regular research at the Kinectrics lab in Toronto. Hugh is owner of ArcWear.com his testing company

They may be contacted at:

e-Hazard.com

13113 Eastpoint Park Blvd.

STE E

Louisville, KY 40223

Office: 502-716-7073

A 2009 change to NFPA 70E

NFPA 70E has long waived the necessity of an energized work permit for such tasks as testing (voltage, current, phasing, infrared and system tuning), circuit identification, and troubleshooting. In 2009, a fourth exemption was added allowing persons to cross the Limited Approach Boundary for visual inspection (130.1(B)(3)).

This newly added exemption allows a qualified person to approach energized equipment for the singular purpose of visually inspecting equipment condition as long as that person does not cross the Restricted Approach Boundary or perform any task. He or she must also wear the appropriate arc flash PPE and follow all required safe work practices.

This eliminates any need for unnecessary paperwork in many areas. Companies may still choose to use a “hot work permit” or an energized electrical permit where conditions indicate. A common example of tasks that may be exempt from permit would be the need to look at a component to obtain a part number, but the most common is infrared inspection of parts for system reliability. Whether an equipment door is opened to verify a component setting, a fuse size or other common work task, a qualified, properly outfitted person may be exempt from a management signature permit for these common tasks under certain conditions.

Anytime such inspections or any work is performed on energized equipment, whether a permit or written approval from management is required or not, persons performing the task must be qualified and must understand the hazards involved. Therefore, the items listed in 130.1(B)(2) must be addressed for all tasks. These items include the equipment and circuits involved in a task; necessary safe work practices; mandatory PPE; the exposed energy sources; knowledge of and proper guarding/marking of the distance of the electrical boundaries (arc flash or shock boundaries); and a job briefing.

Permit required or not, the person who performs such tasks must be fully aware of the increased hazards inherent to energized work and be qualified to work safely around those hazards.

By Vickie Frost, Hugh Hoagland & Bill Shinn

Vickie, Hugh and Bill are Sr. Partners in eHazard the leading electrical safety and arc flash training company.

Vickie Frost is a technical writer and has been involved in electrical safety for over 20 years.

Hugh Hoagland & Bill Shinn, are members of ASTM F18 and Hugh is taskforce chair of many arc test methods. Bill has over 40 years electrical safety experience and is a Professional Electrical Engineer, retired from Alcoa.

Hugh does most of the world´s electric arc flash testing on clothing and PPE and does regular research at the Kinectrics lab in Toronto. Hugh is owner of ArcWear.com his testing company

They may be contacted at:

e-Hazard.com

13113 Eastpoint Park Blvd.

STE E

Louisville, KY 40223

Office: 502-716-7073

www.e-hazard.com

These are usually only available to those who attend the conferences. This is a good overview of the standards relating to arc resistant equipment (NOT PPE).  Arc Resistant equipment are usually motor control centers or switchgear which do not allow more than 1.2 cal/cm2 of energy to escape when an arc occurs internally in the [...]

This brings the proposed fines to over $2 million for the USPS for electrical safety.  This is a huge amount for electrical safety fines.
Click to see the OSHA press release for electrical safety fines for the Scarborough, ME USPS Postal facility $443K June 2010.
Portland, OR Citation $77K June 2010.
Baton Rouge, LA Citation $97.5K June 2010.
Two [...]

A Hoschton, Ga., electrician died today after he was struck in the face by a live wire in front of a Martinez residence.

Workmen survey the scene Thursday after a co-worker was shocked by electricity. William Bret Ward, 45, was hit in the forehead by a live wire at about 10:30 a.m. while working on a ground transformer at a home on the 3900 block of Braddock Street, Columbia County Coroner Vernon Collins said.

“(He) was pulling a wire into it and apparently his head came in contact with the current, and it electrocuted him,” Collins said.

Ward, a worker with Utility Lines Construction Services Inc., was wearing protective gloves and rubber sleeves when the wire hit him, Collins said.

Ward’s co-workers performed CPR on him until Martinez-Columbia Fire Rescue and EMS crews arrived at the scene.

“It was just too much for him,” Collins said.

Ward was pronounced dead at about 11:30 a.m. at Doctors Hospital.

This interpretation makes it clear that OSHA can cite electrical hazards which are “recognized” under the “General Duty Clause”.  This interpretation also clarifies the responsibilities of the “controlling employer”.  This is one of the first mentions of NFPA 70E by OSHA and we are seeing the results of the citations today.
OSHA states in the interpretation, [...]

Wearing the right PPE is critical but other provisions to prevent arc flashes and lower incident energies in incidents are part of CSA Z462 and NFPA 70E.  These provisions prevent many of the incidents in the workplace.
Click here to read the story of the arc flash fine in Canada at OH&S Insider.

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Schneider Electric (a top NFPA 70E compliance company) cited for electrical hazards after an employee electrocution.  It is tough to change the electrical culture.  Companies with leading edge technologies and safety programs have a tough time getting the word down to the lower level workers.  Electricity can kill you. I’m sure Square-D made changes to prevent this [...]

HVAC system kills one, injures one. One worker dead another with 3rd Degree burns on hands. LO/TO not followed?  HVAC workers among the most likely to die of electrocution. 
Click here to read the story.

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