When is it permissible to use chains or cables around the tank shell to move the tank?

Using chains or cables around the tank shell to move the tank is never permissible due to safety and structural integrity concerns. This method can potentially damage the tank, leading to leaks, environmental contamination, or structural failure. Proper procedures for tank handling emphasize the need to use equipment specifically designed for lifting and moving tanks, which avoids applying stress to the shell that chains or cables might cause.

Additionally, regulations governing underground storage tanks prioritize the protection of both the tank and the environment. Using inappropriate methods like chains or cables poses serious risks, not only undermining the tank’s structural integrity but also increasing the likelihood of accidents during transport. Therefore, the safest approach is to avoid any method that could jeopardize the tank's condition, which reinforces the rationale behind the response that such actions are never permissible.