What is the minimum thickness of plastic sheathing required between copper piping and concrete?

The minimum thickness of plastic sheathing required between copper piping and concrete is determined based on the need to prevent electrolysis and corrosion caused by the interaction of the copper with the concrete. The correct thickness of 0.008 inch (which is represented by the answer provided) is specified in the International Plumbing Code to ensure adequate protection.

This thickness is sufficient to provide a barrier against aggressive agents found in concrete, which can lead to deterioration of the copper over time. Additionally, the 0.008 inch thickness is considered a practical balance between effective protection and material usage, maintaining the integrity of both the piping and the concrete.

Understanding why other thicknesses do not meet the code is essential. For example, a thickness that is too low may not adequately prevent corrosion, while opting for a thickness that is unnecessarily high may lead to increased costs and material waste without providing additional substantive protection.