When practical, the workpiece for welding, cutting or heating is moved to a designated safe location; if it cannot readily be moved, all nearby fire hazards that can be moved are relocated to safety or otherwise protected. Where the object cannot be moved and not all fire hazards can be removed, positive means are used to contain sparks, slag and heat and shield the fixed fire hazards. Hot work is not done where flammable paints being applied, other flammable compounds, or heavy concentrations of dust, create a hazard. Suitable fire extinguishing equipment must be at hand in the work area immediately and kept ready for instant use. When normal precautions are not enough, additional personnel are assigned to watch for fire during the hot work and for long enough afterwards to make sure no fire can develop, and they are instructed on the specific fire hazards expected and on using the firefighting equipment provided. Work on walls, floors and ceilings calls for the same precautions on the far side as on the working side, because sparks or conducted heat can start a fire in the adjoining area. To prevent fires in enclosed spaces from gas escaping through leaking or badly closed torch valves, the torch's gas supply is positively shut off at a point outside the space whenever the torch is not going to be used or will be unattended for a substantial time such as over lunch; torch and hose are taken out of the confined space overnight and at shift change, and disconnected open-ended hoses are removed from enclosed spaces immediately. Drums, pails and other containers that hold or held flammable liquids are kept closed except while contents are being removed or transferred, and empty ones are taken to a safe area away from hot work and open flame. Drums, containers or hollow structures that held toxic or flammable substances are, before hot work, either filled with water or thoroughly cleaned, ventilated and tested; steel pipelines carrying natural gas follow DOT 49 CFR part 192. A vent or opening must be provided on any drum, container or hollow structure before it is heated, so built-up pressure can escape.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.