Construction worker back mounted heater - GIF

[nova_robotics]

Not necessarily, I've seen the times when I would have gladly strapped a fire pot to a board on my back if I had thought of doing it. As to how long before the plywood is charred enough to reach ignition point depends on whether or not there are holes in the tubs on the side next to the plywood.

I used to work in -50C in the oil patch. I get it. But how would the heat get through the plywood to warm you up?