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Arc flash safety

What are the best available options?

By Michael Carolan

Are you safe from Arc Flash?

There’s an increased awareness of the dangers associated with working close to electrical circuits because many serious accidents have occurred.

With so many employees now working in close proximity to electrical equipment, these employees are potentially at risk from serious injuries, especially if the correct Personal Protection Equipment (PPE) is not selected.

If you have electrical equipment operating at 50V or higher, you should take every precaution to protect your company’s most valuable assets – your employees.

There is currently a challenge in Australia for companies, which want to maintain a comprehensive electrical safety program, in that there is no Australian Standard available which gives companies a complete overview and direction on electrical safety.

Standards Australia is currently working on producing a standard for safe work practices when working with high voltage electricity, however this could be some 12-18 months before a draft is available.

While ASNZS 4836: 2011 (Safe working on or near low voltage electrical installations and equipment) was recently published, this standard is lacking in that it provides advice for appropriate PPE, but does not give any direction on how to select the right level of PPE.

For instance, table 9.1 of the standard outlines personal protective equipment which should be used by workers working on or near exposed energised conductors or live
conductive parts.

The table lists that an arc flash suit and hood rated to a minimum of 40 calories (cal) should be used.

This is a high level of protection and a 40 cal rated suit is quite bulky and not really necessary if the arc flash potential is only 12 cal in which case a lighter weight suit could be worn providing increased comfort and mobility for the worker.

The standard does not provide any methodology for calculating an arc flash potential which is important as the potential calorie rating for the system being worked on needs to be known so the appropriate and most comfortable PPE can be selected.

While it is good to have some direction, PPE that is more targeted to the application would be more applicable.

In the absence of a complete Australian Standard, NFPA 70E can help to protect your valued employees and create a safe working environment.

The NFPA 70E standard is a comprehensive guide to electrical safety and covers establishing an electrically safe work condition, (ie working de-energised where possible, lock out/tag out), determining approach boundaries, knowing your Hazard Risk Category (HRC) and determining the proper Personal Protective Equipment (PPE) for each category.

NFPA70E lists a wide range of equipment and common tasks performed, and provides hazard/risk category ratings (ratings from 0 to 4) to help select appropriate PPE.

For example, if the equipment was metal clad Switchgear 1kV though 38kV and a worker was working on control circuits with energized electrical conductors and circuit parts 120V or below exposed.

The standard classifies this task as a hazard/risk Category 2 and states rubber insulating gloves and insulated hand tools are required.

A task classified as a hazard Risk Category 2 has a calculated incident energy level of 4 to 8 cal.

Table 130.7 of the standard then outlines the type of PPE required for each hazard risk category.

NFPA 70E also includes calculation methodology, which can be used to determine the incident energy (potential calorie rating) of an arc flash, so the correct level of protection can be selected whilst ensuring workers will be as comfortable as possible.

Over the years, PPE has changed and advanced due to worker demand and technological advancements.

The industry has begun to understand the importance of not only developing and implementing an electrical safety program under NFPA 70E, but they have also come to understand the difficulty in ensuring the worker is actually using the issued PPE while in the field.

It is important to understand that where there is a potential for an arc flash and the incident energy (calorie) rating has been determined, products must be selected which will provide adequate protection against this rating.

For example, if the incident energy level has been calculated at 8 calories, then a faceshield should be worn which has a calorie rating of 8 cal or higher.

A clear polycarbonate faceshield, goggles or eyewear will not provide sufficient protection and will be likely to result in significant burns as well as melting to the wearers face if they were exposed to an arc flash.

Face shields were once the major complaint for most workers. In the past, arc flash protection face shields were typically dark and color tinted, making wire color identification and tasks performed in dimly lit areas, all but impossible.

Also, while wearing an arc flash protection face shield, a worker needs to lift his/her face shield from time to time. Most face shields don’t lock into position when lifted or lift high above the worker’s head creating work hazards and lower productivity.

Salisbury by Honeywell has developed a new face shield that addresses these issues and more. The Salisbury by Honeywell AS1200 is a face shield that stows in a balanced position, centered over the top of the hard hat, creating a comfortable and locked “up” position for the worker. This unit is easy to use and wear and can increase worker productivity. The unit also utilizes nanotechnology to provide a clearer, more transparent visor for improved visibility and can be used in applications where a faceshield up to 12 cal/cm2 (NFPA 70E HRC 2) is necessary.

The industry is always looking for more comfortable electrical PPE solutions for their workers so they may perform their tasks safely.

Technology is keeping pace with manufacturers developing new and better products every day, and while we eagerly await the release of an Australian Standard for direction on electrical safety, industry should continue to consult the NFPA 70E standard to ensure employees are fully protected with the appropriate PPE when working in low and high voltage applications.

* Michael Carolan is Senior Product Manager at Honeywell Safety Products

Honeywell Safety Products
Ph: 1300 139 166
www.honeywellsafety.com