| Authorising the work | HSE’s HSG250, written for the petroleum, chemical and allied industries, describes hot work permits and asks whether permits clearly specify a time limit. For work in hazardous places or hazardous activities under DSEAR, its Schedule 1 lists permits issued before the work starts by a person with responsibility for this. | The person responsible for authorising cutting and welding inspects the area and designates the precautions, preferably in a written permit. | The section sets fire precautions but does not mention a permit; a written permit is the site’s or contractor’s rule. |
| Move the work, or the hazards | Clear away wood, fabric, cardboard and other flammable material before starting. | Move the object, or take movable fire hazards to a safe place; guard what cannot be moved; if neither is possible, no welding or cutting. | Move the object to a designated safe location when practical, or take movable fire hazards to a safe place or protect them. |
| Distance for combustibles | No fixed distance in HSE’s guidance; sparks and slag can travel a considerable distance. Use your site rule or insurer’s. | Relocate at least 35 feet (10.7 m) where practicable, otherwise flameproofed covers or shields; sweep combustible floors for 35 feet. | No distance given: confine the heat, sparks and slag where hazards cannot be removed. |
| Openings and the other side | Sparks and slag can start fires in adjacent rooms. | Protect material below floor openings and cracks and beyond wall holes, doorways and windows; on metal walls, prevent ignition on the other side, with a fire watch there if combustibles stay. | The same precautions on the opposite side of walls, floors and ceilings as on the side being worked on. |
| Sprinklers, atmospheres and containers | DSEAR: identify areas where explosive atmospheres may occur and avoid ignition sources there. HSE’s INDG314 covers small tanks and drums. | Not permitted in sprinklered buildings while protection is impaired (the sprinklers go back into service before the work), in explosive atmospheres, or on used containers until thoroughly cleaned. | No rule on impaired sprinklers. Not where flammable paints, compounds or heavy dust create a hazard; containers filled with water, or cleaned, ventilated and tested. |
| Fire watch during the work | Where hot work cannot be done in a safe area or combustible material cannot be removed. | Where more than a minor fire might develop, or in four listed conditions, such as appreciable combustibles closer than 35 feet. | Extra personnel when normal fire prevention precautions are not sufficient. |
| Fire watch after the work | At least 30 minutes, which may need to be 60 where an ignition may be difficult to detect or slow to develop. | At least half an hour after welding or cutting is completed. | A sufficient period after the work to ensure no possibility of fire exists. |