- A compartment in which hot work is to be undertaken should be cleaned and ventilated until tests of the atmosphere indicate 21% oxygen content by volume and not more than 1% LFL.
- It is important to continue ventilation during hot work.
- Adjacent cargo tanks, including diagonally positioned cargo tanks, should either have been cleaned and gas freed to hot work standard, or cleaned and hydrocarbon vapour content reduced to not more than 1% by volume and kept inerted, or completely filled with water.
- Other cargo tanks which are not gas free should be purged of hydrocarbon vapour to less than 2% by volume and kept inerted and secured.
- On a vessel without an inert gas system, all cargo tanks except tanks containing slops should be cleaned and gas freed.
- Slops should be placed in a tank as far as possible from the hot work area, and the tank kept closed.
- All interconnecting pipelines to other compartments should be flushed through with water, drained, vented and isolated from the compartment where hot work will take place.
- Vapour lines and inert gas lines to the compartment should also be ventilated and isolated.
- Heating coils should be flushed.
- All sludge, cargo-impregnated scale, sediment or other material likely to give off vapour which is flammable, should be removed from an area of at least 10 metres around the area of hot work.
- Special attention must be given to the reverse sides of frames and bulkheads.
- Other areas that may be affected by the hot work, such as the area immediately below, should also be cleaned.
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