Absolutely no need to remove the tank etc.
A competent welder with the right equipment will weld in the repair sections without the risk of fire.
Oxygen/Acetylene welding techniques are no longer used for this type of welding, so no naked flames, which would be a fire hazard.
I have done this job over half a dozen times in the shop over the years and as a guide it takes around 1.5 hours per side to carry out the welding, using an OEM repair section.
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