Rigid support shall be provided at changes in direction for horizontal pipes of what sizes?

Rigid support is essential for maintaining the integrity and function of horizontal piping systems, particularly at points where the pipes change direction. According to the International Plumbing Code, horizontal pipes that are 4 inches and larger require rigid support at each change in direction. This requirement ensures that the pipes remain stable and prevents undue stress on joints and fittings that could lead to leaks or failures.

Using rigid support for larger pipe sizes is necessary because as the diameter of the pipe increases, so does the weight and momentum when the flow changes direction. Proper support helps distribute the load evenly and prevents sagging or misalignment that can occur over time, particularly in environments with temperature fluctuations or vibrations. Hence, pipes of this size must adhere to the code to ensure long-term durability and reliable operation of plumbing systems.