What is the minimum thickness required for cement mortar lining in pipes sized 20 inches and above?

For pipes that are 20 inches in diameter and larger, the minimum thickness required for cement mortar lining is specifically set at 1/2 inch. This thickness is established as a standard to ensure adequate protection against corrosion and to maintain the structural integrity of the pipe line.

Cement mortar lining serves multiple purposes including providing a protective barrier against the corrosive substances that might be present in the water being transported, enhancing the smoothness of the interior surface to reduce flow resistance, and aiding in joint sealing. A minimum thickness of 1/2 inch is necessary to achieve these goals effectively. It ensures that the lining is robust enough to withstand hydraulic pressures and potential wear from the transported materials.

Thinner linings, such as 1/4 inch or 3/8 inch, would not provide enough durability or protection against abrasion and chemical reactions, which could lead to premature failure of the lining and, ultimately, the pipe itself. A thickness of 5/8 inch is generally more than what is required in most instances for pipes of this size, potentially leading to unnecessary costs and material usage.