Arc Flash & Electrical Safety

Friday, January 02, 2009

Discover Common Mistakes In Calculating Arc Flash Hazard Levels And How To Avoid Them

An article by Peter R. Walsh in the December 2008 CSE Live
describes using IEEE 1584 for calculating arc flash hazards, including an overview of the calculation procedure. The article then points out two common errors in determining arc flash hazard levels: assuming a high fault current and assuming accurate values not necessary.

You can read the complete at: http://www.csemag.com/article/CA6623727.html

Labels: Arc Flash Calculations

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Thursday, September 04, 2008

IEEE / NFPA joint research update

The IEEE / NFPA Arc Flash Collaborative Research Project is ready to begin testing that, ultimately, should lead to more accurate and effective arc flash standards. An article on the IEEE site provides background on the project.

The goal of the IEEE / NFPA joint research is to create rigorously-tested models of arc flash phenomena that can serve as a reference in creating improved formulas and safety codes. In addition to exploring the effects of varying voltages, arc gaps, enclosures, and so forth on incident energy, researchers will be investigating secondary hazards of arc flash such as toxic gases, sound waves, and ultraviolet radiation.

A network of laboratories around the world, carefully vetted by IEEE / NFPA project members over the last year, will be participating in the study. Total costs of the research are expected to be $6.5 million, of which more than half has already been raised. Ben Johnson, project co-chair, stated: "I expect that we’ll gain information that can lead to improved equipment...if we can save just one life, all this is worth doing.”

Labels: Arc Flash Calculations, NFPA 70E, Understanding Arc Flash

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Monday, June 16, 2008

Qualify Providers Before An Arc Flash Analysis

An article in Plant Engineering Live, by Joseph Weigel, of Square D Services, Schneider Electric, provides some recommendations for selecting an arc flash analysis provider.

The article begins by providing an overview description of an arc flash analysis followed by a short discussion of standards. It then talks about the factors that should be considered when selecting a provider of your arc flash analysis.

The article concludes by saying:

"Purchasing an arc flash analysis for an industrial facility is very important for electrical safety standard compliance and also is required in order to provide the safest possible workplace for employees. However, like any product or service, when purchasing an arc flash analysis, one tends to get what one pays for, which is why qualifying providers should not be taken lightly. But more importantly, a facility owner or manager should also be careful not to be wooed by low bids.

Thus, a careful and thoughtful approach to an arc flash analysis purchase and qualifying providers, can help ensure the best possible result for a company’s investment."

Labels: Arc Flash Calculations, Arc Flash Products

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Wednesday, May 21, 2008

An Arc Flash Primer

An article in today's online edition of Consulting-Specifying Engineer by Nicholas Chalhoub, Senior Electrical Engineer with CH2M HILL, is called "An Arc Flash Primer".

As most other articles about arc flash do, Mr. Chalhoub begins this article with an explanation of what arc flash is. I found it refreshing that he began his description of arc flash with the statement "The primary cause of arc fault is human error." He then describes how human error leads to arc flash and how arc flash hazards can be reduced.

The next topics are proper design, preventative maintenance and arc flash calculations. He discusses the goals and objectives of arc flash calculations and provides an example calculation. He then points out:

"After these calculations are generated, the arc flash and shock hazard tags must be printed and placed on the specified equipment. The flash hazard boundary, flash hazard, and the category type should be listed on the tag. Many maintenance and safety personnel have been requesting that the limited, restricted and prohibited approach be listed also."

You can read the entire article at: CSE Magazine

You can learn about arc flash labels and tags on our web site.

Labels: Arc Flash, Arc Flash Calculations, Arc Flash Labeling

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Wednesday, May 07, 2008

Electric Power Conference

Joseph Deane is principal owner of KTR Associates, spoke about arc flash at the Electric Power Conference this morning. Mr. Deane has over 25 years of experience as an Electrical Engineer, Project Manager, and Executive, working in both the industrial and utility business sectors.

The following is an abstract of his presentation:

The NFPA 70E standard was created at the request of OSHA in 1979 to recognize the difference between design and workplace safety. The National Electric Code (NEC) provides the installation (design) standard while the NFPA 70E is the workplace safety standard.

NFPA 70E describes employer responsibilities and recommendations on topics such as employee training, safety-related work practices, tagout procedures, calculating flash protection boundaries and PPE requirements. The current standard recognizes arc flash as a serious hazard and establishes PPE requirements that apply when working around energized equipment.

Why is the NFPA-70E Standard Important? Because following the NFPA-70E standard may save a life. Hazardous arc flashes can occur in any electrical device in which energy is high enough to sustain an arc. The heat exposure due to an electrical arc can produce first-degree burns, permanent blindness, or even death.

In an effort to reduce the extent of potential injuries NFPA-70E specifies boundaries within which flash protection (PPE) is required.

The National Safety Council estimates that an average of more than one fatality a day occurs while working around electrical equipment. Of these fatalities, more than half occurred while working on energized equipment rated 600 volts or below. In addition, five to ten electrical “arc flashes” occur in the workplace everyday. The medical costs for an individually exposed to an electrical arc flash is around $12 to $20 million.

Employers need to include both shock and arc hazard identification in their safety programs.

When working on electrical apparatus (switchgear, panelboards, motor control centers, etc.) the incident energy or available fault current to produce an arc flash needs to be clearly identified on each respective enclosure or piece of electrical equipment. As a part of that label, when employees must work within the flash protection boundary, it is important to include the incident energy. Producing a Flash Hazard Analysis can do this.

Does OSHA recognize the NFPA 70E? Absolutely. OSHA has recently updated their electrical standards to reflect the latest in both the NEC and NFPA 70E standard. OSHA will cite companies for non-compliance with 29 CFR 1910.335(a)(1)(i) which requires the use of protective equipment when working where a potential hazard exists and 29 CFR 1910.132(d)(1) which requires the employer to provide an assessment of the workplace for hazards and the need for personal protective equipment.

OSHA also utilizes the “General Duty Clause” which states, "each employer shall furnish to each of its employees a place of employment that is free from recognized hazards that are likely to cause death or serious physical harm."

Labels: Arc Flash, Arc Flash Calculations, Arc Flash Labeling

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Thursday, June 07, 2007

Is Your Electrical PPE Adequate?

Yesterday I recommended an article in Occupational Hazards magazine that presented a variety of problems with OSHA's proposed rules to reduce electrical burn injuries. Today I'm recommending an article from Maintenance Technology magazine that provides more details, including information based on two recent IEEE papers.

This article looks at the recent scientific research into what happens during an arc flash. The article concludes that:

"Recent research into arc flash phenomena, however, indicates that workers could be under-protected against the heat generated during an arc flash event. Test results presented at IEEE conferences and at the 2007 IEEE Electrical Safety Workshop show that different configurations of electrodes (conductors) yielded heat energy higher than current predictions due to the directional nature of the arc development. Additionally, initial tests of PPE, when placed within this directional plasma flow, did not provide the level of thermal protection predicted by its APTV."

An interesting result of the research is that it shows the design of electrical equipment has a major impact on the severity of the arc flash. Improved designs can reduce the intensity of the arc flash by 50%. It also shows that current-limiting fuses may reduce the heat energy to workers exposed to the plasma flow from an arc flash.

Labels: Arc Flash, Arc Flash Calculations, Arc Flash PPE

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Wednesday, January 17, 2007

Arc Flash Boundaries in Small Facilities

I noticed an article published on Reliability Web.com that addresses arc flash safety in small facilities. This is a topic that is not commonly covered. The article by John C. Klingler, P.E. of Lewellyn Technology states:

"In small facilities such as small businesses and offices that only use 240 volts and less and have minor power requirements (primarily lighting and receptacle loads), it may not be practical or economical to calculate arc-flash boundaries. It appears the authors of 70E realized this, so they established a default flash boundary that can be used without calculations."

If you work in a small facility, you may find this article about Understanding NFPA 70E to be useful.

Labels: Arc Flash Calculations

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Tuesday, January 16, 2007

Duke Power Heat Flux Calculator

The Duke Power Heat Flux Calculator is free software that calculates the heat flux on a surface at a specified distance from an arc flash. The parameters of the arc flash can be entered including available amps, voltage and the arc gap.

This software is now available for downloading from the NFPA 70E Arc Flash Labeling site. (Heat Flux Calculator Download Page).

This software is available on a number of web sites. What makes this download desirable is that the software has been packaged in an automatic installation. A single click of a button takes care of the complete installation. The installation will copy the files to your hard drive, put an icon for starting the software on your desktop, and also installs icons for the software and the documentation on yout START > PROGRAMS menu. An option for automatically uninstalling the heat flux calculator is also provided.

All of the other downloads require you to download a zip file, unzip it, place the files where you want them located and then create your own icons.

If you have use for a heat flux calculator, the www.labelprinters.org web site is the place to download it from.

Labels: Arc Flash Calculations

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Monday, January 15, 2007

Putting Arc-Flash Calculations into Perspective

"The number of arc flash incidents in the United States is greater than many engineers realize since most accidents don't make the daily news. Chicago-based Capelli-Schellpfeffer, Inc. reports that five to 10 arc-flash injuries that result in hospitalization occur every day."

This is the opening paragraph of an article in Occupational Hazards magazine. The article takes a deeper look at the engineering and math behind arc flash safety, making the point that this information is critical to preventing arc flash injuries.

"Although OSHA doesn't directly state what to do about arc-flash hazards, OSHA 29 CFR 1910.132(d)(1) requires employers to evaluate the workplace for hazards. And based on these assessments, the employer must select and require the use of appropriate personal protective equipment (PPE) for its employees."

The article discusses IEEE Std. 1584. This standard focuses on the direct cause of arc flash injuries, the radiated heat or incident energy produced by an arcing fault that falls on a given surface. The article covers various factors that effect the energy level in an arc flash incident, as calculated using the formulas given by IEEE Std. 1584.

The article concludes with practical advice for providing arc flash PPE and protection.

Labels: Arc Flash Calculations

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