What piece of equipment provides a seal to avoid air and gas emissions in plumbing systems?

A P-trap is crucial in plumbing systems as it serves to create a water seal that prevents the escape of sewer gases into living spaces. It is typically located under sinks, bathtubs, and other drainage fixtures. The design of a P-trap allows it to hold a small amount of water, which acts as a barrier against air and gas emissions, effectively maintaining a sanitary environment and preventing foul odors.

The P-trap’s water seal is integral for proper functioning. If the water in the trap evaporates, it may expose the interior of the plumbing system to harmful gases, which can be detrimental to health. This is why P-traps are required by plumbing codes to ensure safety and sanitation within buildings.

While other options may pertain to functions in plumbing or air management, they do not fulfill the specific role of creating a seal to prevent air and gas escape as effectively as a P-trap does.