When concealed piping requires protection against physical damage, the steel shield plates shall be not less than _____- inch thick.

In plumbing installations, particularly when dealing with concealed piping, it's crucial to ensure that these pipes are protected from potential physical damage. This is especially true in areas where the piping might be exposed to impacts from tools, equipment, or other objects that could compromise the integrity of the pipe.

The specification for the thickness of steel shield plates used for this purpose is determined by building codes and standards, which establish that the plates need to be a minimum thickness to effectively absorb impacts and prevent damage to the piping behind them. The minimum thickness of 0.0575 inches is sufficient to provide this level of protection, making it the correct answer.

Having proper thickness in the shielding material is vital in preventing pinhole leaks or ruptures in the piping system, which can lead to costly repairs or extensive water damage. Therefore, adherence to the minimum thickness standard is essential for ensuring the longevity and safety of the plumbing system.