What is required for water supply and drain pipes under lavatories and sinks?

Water supply and drain pipes under lavatories and sinks must be insulated or configured in a manner that prevents contact with other surfaces to ensure safety and proper functioning. This requirement is essential for several reasons.

First, insulation protects the pipes from temperature fluctuations that can lead to condensation and water damage. Secondly, minimizing contact between pipes and structural elements helps to reduce noise and vibration, which can be generated by flowing water. This consideration is particularly important in living spaces where such disturbances can be disruptive.

Moreover, configuring pipes to prevent contact helps to mitigate potential corrosion that can occur when different materials interact or rub against each other. Overall, the correct option highlights the importance of installing plumbing components in a way that promotes longevity, safety, and effective water management in a household setting.