My feeling about welding in THAT building????????
You might as well spray gasoline before you start, it will go up in flames eventually.
The issue is not the floor, it is the entire structure.
A spark goes somewhere, smoldering starts, in the middle of the night, you hear the fire trucks driving up,,,,.
Those welding/cutting sparks go 10 feet,,, land in some dust and/or cob webs, and the smoldering starts.
You could do a water washdown after welding EVERY time.