FAQs

Frequently Asked Questions


Voltage does not determine the arc flash hazard. Knowing the voltage is only one piece of determining Arc Flash PPE. The electrode orientation, available fault current (amps), the working distance between the worker and the equipment, the clearing time of the circuit protection device, the spacing between conductors or from a conductor to ground, the number of phases, whether the conductors are in an enclosure, and the equipment configuration must all be considered when determining the potential severity of an arc flash hazard. NFPA 70E provides two methods for the selection of arc flash PPE as part of an overarching requirement to complete an arc flash risk assessment. The two selection methods are;

  • Incident energy analysis method. Often referred to as an “arc flash study”, requires engineering calculations to determine the potential thermal incident energy in the event of an arc flash. Arc flash PPE is then selected so the arc rating (protection) matches or exceeds the calculated incident energy. Both the thermal incident energy and protective arc ratings are calculated as calories per square centimeter (cal/cm2).
  • Arc flash PPE category method. Otherwise known as the “table method”, involves a simplified approach using the tables from within the Standard to determine a category number from 1-4 and corresponding arc flash PPE minimum requirements. The table method requires validation of the parameters used in the creation of the categories, otherwise the user is forced into using the incident energy analysis method. Refer to Oberon’s catalog on page #5 for arc flash PPE category product information.

Either, but not both, arc flash PPE selection methods can be used on the same piece of equipment. The engineering calculations used in the incident energy analysis method cannot be used to specify an arc flash PPE category. Keep both methods separate and document your decision making processes within your company’s Electrical Safety Program.

The bottom line is that you can’t rely on voltage alone to figure out what arc flash PPE you need. NFPA 70E requires the employer to complete an arc flash risk assessment. If additional protective measures are required, arc flash PPE can be applied as a control to mitigate the risk of an arc flash. Refer to the latest edition of the NFPA 70E Standard to learn more about the requirements for an arc flash risk assessment.

There are three different types of arc-rated flame resistant (FR) fabrics available on the market; Treated non-inherently FR fabrics, Inherently FR fabrics and Treated Inherently FR fabrics. Treated non-inherently FR fabrics, either 100% cotton, or cotton blends, have no flame resistant properties and require a chemical treatment application to become flame resistant. (FRT) Inherent fabrics are engineered to be flame resistant (IFR), and there is no chemical that needs to be added to them for their protective capabilities. Treated Inherently FR fabrics are when traditional Inherently FR fabrics are treated using a similar process to non-inherently FR fabrics, resulting in a lightweight inherently FR fabric that provides more protection. Regardless of the type of FR fabric, the material must still be arc-rated with either an Arc Thermal Performance Value (ATPV) or an Energy Break-open Threshold (EBT).

Arc Flash PPE is tested to determine its protective ability, this is called an arc rating. This testing is done on the fabric or a finished product using various different testing methods according to applicable Standards. Arc-rated clothing provides insulation that protects a worker from the thermal incident energy caused by an arc flash incident.

There are various different types of arc ratings. In North America, the most popular product options have an ATPV or EBT rating. An arc rating is reported as either ATPV or EBT, whichever is the lower value. The ELIM is a new way to evaluate the arc thermal resistance properties to select PPE with a lower risk of a worker skin burn injury. All of these values are provided in calories per square centimeter (cal/cm2).

ATPV: Arc Thermal Performance Value, the incident energy level at which there is a 50% probability of sufficient heat transfer to cause the onset of a second-degree skin burn injury.

EBT: Break-open Threshold Energy, the incident energy level at which there is a 50% probability of the formation of holes or tears in the layer closest to the skin.

ELIM: Incident Energy Limit, the highest incident energy data point without breakopen and without reaching the onset of a second-degree skin burn injury

The most common type of arc rating is the Arc Thermal Performance Value, or ATPV. Selecting PPE with an arc rating that matches or exceeds the highest level of potential thermal incident energy exposure from an arc flash incident, is critical in protecting your electrical workers. It is critical to know the incident energy potential of the equipment in your electrical environment to effectively choose the correct Arc-Rated PPE with the appropriate arc-rating.

 

The NFPA 70E Standard requires that all arc flash PPE is pre-use inspected. Refer to Oberon’s resource section of the website for literature resources including User Guides and Storage, Use, Care & Maintenance files. While inspecting your arc flash faceshield if you identify a problem do not use the product until the issue has been repaired, cleaned or replaced. When pre-use inspecting your Oberon arc flash suit you should inspect each item one at a time.

 

The following steps apply when pre-use inspecting your Oberon arc flash faceshield;

  • Check the faceshield visibility, inspect for excessive scratching. If visibility is impaired or the shield is cracked or damaged remove from use (replace with appropriate lens).
  • Manually adjust the shield mounting mechanism (adapters) to ensure wing nuts are firmly in place, do not over tighten or the shield won’t be able to operate correctly.
  • Inspect adapters for cracks or damage, ensure fingers are locked into hard hat slots.
  • Check hard hat slots and inspect for cracks that could allow the adapter to slip out.
  • Ensure the nuts and bolts fastening a lower chin guard (double crown) are tight before use.

The NFPA 70E Standard requires that all arc flash PPE is pre-use inspected. Refer to Oberon’s resource section of the website for literature resources including User Guides and Storage, Use, Care & Maintenance files. While inspecting your arc flash suit if you identify a problem do not use the product until the issue has been repaired, cleaned or replaced. When pre-use inspecting your Oberon arc flash suit you should inspect each item one at a time.

 

Refer to Oberon’s Sizing Guide section of the website. Alternatively, an Oberon Representative can help arrange for an arc flash suit sizing kit to be provided for your workers to use. The proper garment size will ensure electrical workers are protected, comfortable and productive. Arc flash suit sizes should be selected to be loose fitting over top of the worker’s uniform or everyday clothing. When sharing arc flash suits be certain to ensure every possible electrical worker has a comfortable size available to wear.

 

Oberon arc flash suits are sold in alpha sizes from Small up to 5XL. All Oberon garments are available in regular (Standard height), tall, extra tall or short vertical measurements. The arc flash suit size must be adequate to completely cover the workers body, not showing the underlayers in any area.

Oberon promotes the use of LED headlamps on all arc flash faceshields and suit hoods to enhance the workers ability to properly see the work task. Oberon has performed limited testing of the products we support. The arc flash exposures were relevant to the protection provided by the arc flash PPE. During testing none of the LED lamps exploded and we observed no signs of concern regarding melting, dripping or continued ignition/after flame.

No, Oberon has been a strong advocate against the use of this type of arc flash suit for the past 20 years. Long Coat with leggings style arc flash suits are a protection concern for workers! If a worker doesn’t kneel or squat with their legs together a large opening is created at the bottom. Furthermore, thermal incident energy can deflect and chimney up inside the long coat. Arc flash suits should be a Hood with either a Coat & Bib-Overall or Coverall. If you have a long coat style arc flash suit it should be replaced.

Oberon arc flash faceshields and suit hood shield windows are available with anti-fog coatings. Before each and every use the anti-fog coating must be activated. Workers must use humidity to activate the anti-fog properties by pulling the inside of the faceshield or hood lens towards them and breathe on the surface. It’s important for your shield lens to be at room temperature for best results.

 

When using an Oberon arc flash suit hood, consider using a hood ventilation system that circulates air to your breathing zone. Oberon’s system delivers the external air directly down the inside of the hood shield window to reduce fogging in extreme conditions.

No, older Oberon hoods that have a green/yellow shield window lens cannot be exchanged for the new clear TCG shield window. When Oberon designed the hoods for the new TCG shield lens, changes were made to the fabric construction and installation method. The new TCG shield lenses have metal snaps that make assembly and disassembly easier for the worker. All older Oberon hoods must be replaced with complete TCG hoods when upgrading to the new technology.

 

The ASTM F2178 Standard requires the hood to be tested as you would use it. This final product testing requirement is critical for the product to perform as needed during an arc flash exposure.