If there is an arc flash will the moisture in the clothing turn into steam and burn you?
Typically arc flash clothing becomes wet or damp due to perspiration or working outdoors in the weather. In one case the clothing becomes damp and in the other, the clothing could be come saturated. The level of hazard depends on how wet the clothing actually is and the intensity of the arc flash.
Although we at Rozel do not claim to be specialists in the field of arc rated PPE we do our best to educate ourselves by listening to and learning from our expert friends and colleagues. Please see the list of references for this article below.
When we perspire our clothing can become damp. Generally, a little dampness does not diminish the protection provided by the clothing. Under the right circumstances anything is possible but a burn due to a steaming effect of perspiration is highly unlikely. Keep in mind we are still much safer with the PPE on than without it. The clothing will not ignite or melt to your skin even if it is damp or wet.
How do we stay safe?
Wear an arc rated or 100% natural fiber non-melting under layer. Keep a change of both outer and undergarments handy on high heat days. Changing into dry garments during the workday can not only reduce risk but keep you a bit more comfortable as well. Treat wet clothing much like clothing that has been contaminated with oil, grease, or other flammable chemicals. change into a clean and dry set as needed.
Observe heat exhaustion protocols
Excessive sweating due to working in arc rated clothing can be a precursor to heat exhaustion or heat stroke. Stop and take breaks in air-conditioned areas if possible. Allow time for the clothing to dry.
Working in adverse weather
When working in a rainstorm your arc rated clothing can get saturated. Under these conditions the risk of injury can increase. In these situations, it would be a good idea to keep a set of arc-rated rain gear on hand. Arc rated rain equipment is readily available from industrials safety supply houses and vendors. Be sure that the gear meets applicable standards for AR/FR rain wear such ASTM-f1891 you do not want to wear standard rain gear that could ignite or melt in an arc flash.
Outer layers such as rainwear do not need to have an arc rating (ATPV) equal to or greater than the incident energy that you are exposed to as long as the arc flash clothing you have on under the rain gear does. See 130.7(C)(9)(b) in the 2021 edition of NFPA 70E for additional guidance.
Thanks to Derek Sang Technical Training Manager at Bulwark for his time and expertise. See Derek’s bio and contact information here. https://www.bulwark.com/bulwark-institute
Tyndale USA. See and read more about the effects moisture has on arc rated clothing by visiting Tyndale USA below.
“Changing into dry garments during the workday can not only reduce risk but keep you a bit more comfortable as well”
Not only a little more comfortable but a little less stinky. 🙂
Now on a serious note, while high visibility vests and fall protection harnesses won’t keep you dry, if you have to them while exposed to an arc flash hazard then they have to be made of arc rated material.
As Brian stated in his article, the ATPV or EBT of the outer AR garments don’t have to meet or exceed the incident energy exposure.
However, personal fall arrest equipment, e.g harnesses, lanyards, SRLs, etc. are required to have an arc rating of 40 cal/cm2 +/- 5 cals per OSHA 1910.269(g)(2(ii). The reason for the arc rating isn’t to protect the worker directly from the thermal energy released from the arc flash. But rather to provide a secondary function, to ensure the fall protection equipment won’t burn, melt or fail if it had to arrest a fall after being exposed to an arc flash.