arc flash analysis and compliance

What is an arc flash?

An arc flash is the light and heat produced from an electric arc supplied with sufficient electrical energy to cause substantial damage or harm, and may cause a fire.

Arc flash accident

Arc flash temperatures can reach or exceed 35,000 °F or approx. 20,000°C at the arc terminals. The massive energy released in the fault rapidly vaporizes the metal conductors involved, blasting molten metal, and expanding plasma outward with extreme force. A typical arc flash incident can be inconsequential, but could conceivably produce a more severe explosion. The result of the violent event can cause destruction of equipment involved, fire, and injury not only to the worker but also to nearby people.

480 volt 3-phase arc flash Demonstration

In addition to the explosive blast, called the arc blast, destruction also arises from the intense radiant heat produced by the arc. The metal plasma arc produces tremendous amounts of light energy from far infrared to ultraviolet. Surfaces of nearby objects, including people, absorb this energy and are instantly heated to vaporizing temperatures. The effects of this can be seen on adjacent walls and equipment — they are often ablated and eroded from the radiant effects.

As an example, the energy released in an arc flash incident is equivalent to 380 grams (approximately 0.8 pounds) of TNT. The character of an arc flash is quite different from a chemical explosion (more heat and light, less mechanical shock), but the resulting devastation is comparable. The rapidly expanding superheated vapor produced by the arc can cause serious injury or damage, and the intense UV, visible, and IR light produced by the arc can temporarily and sometimes even permanently blind or cause eye damage to people.

In this video, we demonstrated an arc flash in a controlled environment. Do not try this at home.

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Are you in arc flash compliance?

If you have employees who have to work around or on electrical equipment, you have a responsibility to protect workers and the public from arc flash hazards. Arc flash hazards must be identified, workers must be trained, and protective measures must be implemented.

NFPA 70E, titled "Electrical Safety in the Workplace," is the heart of U.S. arc flash regulations. It outlines the specific practices and standards to be followed in protecting a workplace from arc flashes and other electrical hazards. The primary focus of NFPA 70E is the establishment of an electrically safe work condition. Compliance with NFPA 70E can show that the employer acted reasonably and properly in providing this protection.

At sys-tek, our market focus is in data centers, hospitals, research labs, and mission crititcal facilities that must remain on line continuously. With that said, we know how to design and operate systems to meet the requirements of NFPA while still keeping systems fully on line and operating. This skill set has been developed over 18 years of completing difficult projects, and we know what we are doing. 

In addition to NFPA 70 E, Section 29 of the Code of Federal Regulations (CFR), Part 1910, Subpart S sets forth OSHA's labor rules for workplace safety around electricity. These rules mandate de-energizing equipment before it is serviced, and using lockout/tagout procedures to mark it while it is powered down. Although OSHA does not regulate arc flashes in explicit terms. However, its rules clearly establish employers' responsibility for workplace safety, requiring them to identify and label electrical hazards and make sure employees are protected from them.

Arc flash compliance requires:

  • Completion of an arc flash hazard analysis
  • Completion of an up-to-date one line diagram of the electrical system
  • Completion and implementation of an electrical safety plan
  • Installation of arc flash warning labels on equipment
  • Use of Energized Electrical Work Permits
  • Training of qualified and unqualified workers 

 

Arc flash data collection

By combining our engineering and field services expertise, we first develop a project plan on how the needed data is obtained for arc flash calculations. Many times, the building owners do not have accurate one-line diagrams of their facilities or accurate records, therefore requiring data to be collected in the field. Using our proven safety methods for data collection, we can either work alongside the facility personnel, or provide all needed personnel to obtain this critical data. Safety is our number one concern, as much of the data needed to calculate the potential arc flash for the electrical systems can be found in areas where an arc flash can occur.

Experience

We have in-depth expertise in providing Ground Fault and Coordination Studies, which results in providing arc flash identification and labeling for medium and low voltage electrical systems ranging from 250 kW to 10 MW. Projects completed include hospitals, data centers, industrial complexes, research laboratories, and higher education facilities. We are hands-on engineers, and know how to provide results and get into the details of any building to obtain needed data for developing accurate results.

Our field services, which include electrical system commissioning, integration testing, start-up, and performance, provide us with an advantage, because we have been on the front lines in the field testing systems and bringing them on line.

 

Implementation

For many of our clients, completely de-energizing equipment to allow for service, maintenance, and upgrades is simply not feasible, and we know and understand these limitations. We have successfully completed hot work permits for projects by combining our engineering and field services skills to obtain accurate knowledge of systems, and preforming accurate arc flash labeling and identification for all electrical equipment in a facility. Once again, it is all about safety, and for many of our clients, continuous operation is not an option; it is mandatory.

Using our project plan, we develop accurate one-line diagrams and collect all necessary field information so we canprovide  accurate computer models of the facility electrical systems using SKM Power Tools Software (www.skm.com). Quite simply, SKM is the gold standard for project analysis flexibility, speed, and database integration. Once the SKM computer model is built, the facility can safely make needed changes and upgrades to their electrical systems with accurate results on fault current, electrical coordination, and potential arc flashes.

 

Deliverable

By using sys-tek for your arc flash compliance, you can rest easy, knowing that the project was done correctly. We provide and install all labeling on electrical equipment for NFPA 70 E compliance and training to operating personnel. The project package will include an accurate one-line diagram for the entire facility, along with a copy of the SKM Power Model database for use on future projects and updates when changes are made to the system.

 

Training

The sys-tek training facility located in Olathe, Kansas, has been used to provide training on arc flash to facility operators, contractors, code enforcement, and for just about anyone who must come near or work on electrical equipment. We provide 4 hour introductory short courses, as well as 3-day intensive training courses. Call 816-229-9009 for our current training schedule.

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Read How to Save Energy, Save Money and get a Promotion. It will tell you everything you need to know about existing building commissioning for your facility.

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