Pounding out is not considered an acceptable form of what in repairing steel pipes?

Pounding out refers to the process of hammering or striking a dented area on a steel pipe to restore its shape. However, this method is generally not regarded as a proper or effective way to repair steel pipes, as it does not address potential underlying structural issues or compromises the integrity of the material. Effective pipe repair should involve methods that ensure the long-term functionality and safety of the pipe, which pounding out does not guarantee.

In contrast, other options such as maintenance, replacement, and cleaning utilize more accepted practices and procedures that ensure the pipe's reliability and safety. Maintenance might involve routine checks and minor repairs that keep the system functioning well without altering the pipe's integrity through methods like pounding. Replacement involves substituting the damaged pipe with a new one, which is a definitive solution. Cleaning typically refers to the removal of deposits or buildups, ensuring that the pipe functions optimally. Thus, while pounding out may seem like a quick fix, it does not suffice as a proper repair technique for steel pipes.