If pipes aren't freezing you're not likely to get frostbite unless you don't dress right.
The contract does have provisions for heat, but it's not defined at what level so that doesn't really help.
Also you mention you're loading in a semi outdoor area, turning on the heat is almost useless there, you're better off asking for some sort of windscreen. It's kinda like driving with the windows down with the heater on, sure some heat is there, but the exposure to the outside and the wind blowing in negates it. You'll freeze, just slower.