Enough fresh air must be supplied to keep workers safe and healthy, with mechanical ventilation where natural supply is inadequate, and heaters used in confined spaces need particular care over ventilation for proper combustion, worker health and limiting temperature rise. Temporary heaters keep the clearances to combustible material in Table F-4 (circulating room heaters 12 inches at sides and rear, radiant room heaters 36 inches, chimney connectors 18 inches) unless listed for smaller clearances. Heaters not suitable for wood floors rest on suitable insulating material or on 1 inch or more of concrete (or equivalent) reaching 2 feet or more past the heater on every side; heaters near combustible tarpaulins or canvas stay 10 feet or more away from those coverings, which are securely fastened against wind. Heaters are set level unless the manufacturer's markings allow otherwise. Salamanders burning solid fuel may not be used in buildings or on scaffolds. Oil-fired heaters have a primary safety control stopping fuel on flame failure (barometric or gravity feed does not count); barometric or gravity feed heaters use only integral tanks, while heaters approved for separate supply tanks may be connected by gravity feed or automatic pump.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.