Hugh Hoagland of ArcWear Article

Dear ArcWear Newsletter Members,

OSHA NEW SUBPART V IN FEDERAL REGISTER

The proposed revision of §1910.269 and Subpart V was published in the Federal Register on Wednesday, June 15, 2005. The official Federal Register notice is available in electronic form at:

 http://a257.g.akamaitech.net/7/257/2422/01jan20051800/edocket.access.gpo.gov/2005/pdf/05-11585.pdf

David Wallis added VERY helpful bookmarks to the official version on his personal website. I would recommend using this to find the pertinent sections. It is the same as the official one but in Acrobat the bookmarks are added for ease of navigation. You will find it at:

OSHA's Electrical Protective Equipment, Proposed Rule

On both of these documents you may right click on the link here and Save As to save on your PC for future reference.
This is one of the last steps before the rule becomes enforceable as law. The document contains substantial changes in the area of electric arc.

The new OSHA standard is similar to the NFPA 70E standard in several ways:

1. Requires a hazard assessment makes a reasonable estimate of the maximum available heat energy to which the employee would be exposed (guidance is given in Appendix F).
2. The standard does not require the employer to estimate the heat energy exposure for every job task performed by each employee. The employer may make broad estimates that cover multiple system areas provided the employer uses reasonable assumptions about the energy exposure distribution throughout the system and provided the estimates represent the maximum exposure for those areas. For example, the employer could estimate the heat energy just outside a substation feeding a radial distribution system and use that estimate for all jobs performed on that radial system.
3. The standard does require the use of a commonly accepted method of estimating arc energy such as (I recommend ArcPro or IEEE 1584 because of the substantial research behind them and both of these are in their second revision).
a. NFPA 70E-2004 Annex D (Available from www.nfpa.org) (raw calculations which can be created in a spreadsheet).
b. IEEE 1584-02 (Available from www.ieee.org).
c. A specific IEEE-PCIC paper which is similar to NFPA 70E-2004 (available from www.ieee.org).
d. ArcPro Software from Kinectrics in Canada (available in the US from HD Electric (available from www.hdelectric.com).
e. Heat Flux Calculator (Available free from www.arcwear.com).
4. Disallows non-FR clothing in many utility conditions. Clothing may not melt or ignite and continue to burn under the utilities™ hazard assessment energy levels. This makes it clear that when cotton clothing ignites it fails the standard. Some got the impression from the previous wording and early test data that cotton was somehow flame resistant, which is not the case unless the cotton is FR treated cotton which meets ASTM F1506 such as Westex, Indura®, UltraSoft® or Indura® FR Cotton.
5. Requires FR clothing under all of the following conditions:
a. The employee is subject to contact with energized circuit parts operating at more than 600 volts,
b. The employee's clothing could be ignited by flammable material in the work area that could be ignited by an electric arc, or
c. The employee's clothing could be ignited by molten metal or electric arcs from faulted conductors in the work area.
6. Requires clothing to be worn which meets or exceeds the Arc Rating of the arc hazard identified the hazard assessment.
7. Makes justification of non-FR clothing more difficult in many situations.
8. Will force innovation in shirting since many arc exposures in utilities will be in the 20 cal/cm² range. Many will be in the 1-5 cal/cm² range but 10-20 cal/cm² is still common. Systems which are fully radial (the instantaneous breakers seeing the end of the line) clear much faster at the end of the line than a system which drops out of instantaneous a mile or so out from the substation which is common in Midwestern and Eastern utilities in the US.

The standard doesn't really address the 480V issue of higher fault current and longer clearing times but it does require FR clothing there. It rightfully does not overkill most 120-240V systems but doesn't mention delta-wye 208-277V systems which have very high fault currents and can produce substantial arc fault energies. Utilities will be responsible for identifying these hazards on their own.