As some organizations repaire tanks
Rules of overhaul tank bottoms are regulated by the project, but in practice, the project is extremely rare. There are repair projects in the "Rules of technical operation of vessels.".
Over 30 years in the construction and repair of tanks had to deal with different ways of replacing the bottoms and roofs. Optimal replacement bottom implies dismantling of the old bottom, tank alignment, installation of a new bottom and reinforcement or without it a lower shell of the tank.
Tanks began to mount with on 50-ies, and sometimes it is necessary to repair the tanks, which had once been repaired. The main danger, which led to the death - a double bottom or roof.
Some craftsmen simply on the bottom of the old mount new one, not even come out bottom chime and joining of bottom and shell weld with the angle. On the roof just lay plates and where necessary tack to the old roof. Over time, resulting in rust between plates accumulates oil. When we come to dismantle the bottom, we do not know, double it or not and there is danger of the double bottom or the roof in the fire and burst.
Such a situation occurred with a company, with the dismantling of the double roof caught fire and cotton, causing the cutter dumped on the ground and from his injuries he died.
Refer to the organizations that have extensive experience of such work, otherwise are possible industrial accidents.