Question: I have been asked by our Radiation Safety (at a nuclear power plant) manager if there is a known hazard with wearing nitrile gloves under voltage rated rubber gloves with leather protectors.
Our company’s consensus is that even if a person were subjected to a 40 calorie event, there would not be enough heat transfer to melt the nitrile gloves if they are worn beneath rubber gloves and leather protectors. I have seen case studies performed by you and others which typically show that voltage rated rubber gloves and leather protectors fare pretty well in an arc flash event. What we don’t know is the amount of heat the hands are subjected to during this event. Have you ever done any studies on this, and if so, what were the results?
Working with the DOE as our client, we are required to follow all of the standards in NFPA 70E. As you know, meltable fibers or materials are not allowed to be worn as an underlayer when wearing arc rated clothing inside an arc flash boundary. But when workers are exposed to possible contamination in a nuclear facility, they are often required to wear latex or rubber gloves. This has always been a concern when our workers are inside radiological areas where they need to wear arc rated clothing.
NFPA 70E very briefly discusses the chance of greater hazards that could be involved while inside an arc flash boundary and will allow for non-arc rated PPE after a risk assessment has been done. I would argue that wearing latex or nitrile gloves is not an issue when the incident energy is low. My problem is I have no factual evidence to prove that argument. I was hoping you did.
If you have not had the opportunity to test this theory, I would be glad to send you voltage rated gloves with leather protectors and nitrile gloves to test this theory and hopefully come up with some results that we could base our risk assessment on. I believe this could help out a lot of sites that require different forms of PPE for radiological work such as respirators and anti C’s clothing.
Answer: ArcWear performed testing for a Canadian electric utility with this issue a few years back.
In our test we never had a nitrile glove placed underneath until the rubber glove ignited. If a rubber glove ignites (which is VERY rare), that would be a problem. If you wanted to use nitrile (I assume for radiation protection), you could also use a Kevlar or some other flame resistant liner or a cotton liner to prevent melting onto the skin directly but that is about all you can do in this circumstance.
No Limits (linked above) has stretchy wool and stretchy cotton liners for wearing under Rubber Insulating gloves which would not melt and help meet NFPA 70E. Or you could use normal cotton liners to meet the wording in NFPA 70E.
NFPA 70E 130.7(C)(12) Exception No. 2:
Non-arc-rated PPE inside AFB permitted when:
- Work to be performed exposes worker to multiple hazards
- Risk hazard assessment identifies level of protection is adequate to address arc flash hazard
Typically this would refer to a respirator or SCBA but could be used for any PPE necessary for an additional hazard.
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Update Feb. 18, 2019: New Article
Specifying Arc-Rated and Flame-Resistant Gloves, by Hugh Hoagland and Stacy Klausing