I’d read the contract through a couple of times just to be sure what the contract requires you to provide Vs your employer (If its not written in the contract its not being provided). Nomex jumpsuits (if required) aren’t cheap.

I’d also recommend a good hard hat liner, watch cap and or ski mask.

If you’re going to be an NDE tech, the one saving grace when it gets cold will be the welds needing to be preheated and if there’s a fab yard, many/most of the piping welds will be done in shelters.

If you’re going in and out of the offices a lot, I’d highly recommend the Carhartt Bibs and Jacket. The quickest way to get cold is to start sweating.