Worked a Power Station, unless been inside one most do not realize stays around 100-105 INDOORS all year, ventilation gets swapped to keep from cooling high stress heated steel components or water systems. Came NFPA 2007, upped at 2010, then 12 and finally as I left in 17. Clothing had to be Fire 'Retarded'(actually Retardant but OK) had to have labeling to prove such. Used to wear ALL cotton and was good until 07, then had to be proved 100% cotton with Fire Retarding, so comes Fire Retarded Clothes, special treatment smells as were soaked in a Dead Bears a$$ for a month, cannot Excessively wash, cannot use fabric softeners, HAD to wear Long Sleeves for Arc Flash Protection, was fine for close to 15 years for me and 20 for others NOT doing so. One in 10,000 gets a Arc Flash event, usually due to inept or fails to follow strict use and established instructions in operating, So everyone gets Punished. Final stages of 12 and 17 FULL Coveralls and hoods to be worn, gear weighed close to 40 lbs, thick as Military Wool Blankets, and OVER all the other clothes we were REQUIRED to wear in 100-105 degree heat. Like to have killed some of our electricians, almost gave ME heat stress ONE TIME.
Safety would not hear the opposite side of Danger with this stuff, so we all grouped and when HAD to rack breakers or work around 'Live(Presumed)' conductors we would change into scrubs then don the gear, was a little better at least bearable.
Worst building I worked in was the "Round Building"(Reactor Containment) at power, best could cool the Ground floor was 105, at the entry hatch 47' up was 118, anywhere around the Alpha Steam Generator access opening was 125, Contamination levels were suspect high so wore Protective Clothing for that, THEN they tried to get us to wear that crap INSIDE there at power! Radiation Protection threw a fit as calculated stay times were short to begin with, this gear cut that by half again where would be subjecting two to three times the personnel numbers to save a POTENTIAL 1/10000. They got it blocked.