What is essential for changes in diameter greater than two pipe sizes in drain pipes?

When changes in diameter greater than two pipe sizes occur in drain pipes, it is crucial to incorporate restraints. Restraints are necessary because they help maintain the integrity and stability of the piping system during shifts in pressure and flow, which can occur with significant changes in size. When a pipe diameter is significantly altered, it can lead to increased turbulence, vibrations, and potential lateral movement. Restraints mitigate these risks by anchoring the pipes securely, preventing movement that could cause leaks, damage, or failure of the drainage system.

This requirement is rooted in the need for structural integrity, ensuring that the transitions in pipe size do not compromise the overall function and safety of the plumbing system. Proper restraints help ensure the long-term reliability of the drains by accommodating the mechanical stresses that arise from flow variations and thermal expansion in larger, more varied pipe sizes.