Which dimension is used to specify condensate line sizes?

Which dimension is used to specify condensate line sizes?

• A. Inside diameter (ID)
• B. Outside diameter (OD)
• C. Diameter is not specified
• D. Both ID and OD allowed

Answer: (A)

Sizing condensate lines is about the interior bore that carries the water. The amount of condensate that can drain relies on the cross-sectional area inside the pipe, so the inside diameter directly determines the flow capacity and ensures fittings, slopes, and traps align correctly. The outside diameter varies with material and wall thickness and does not reflect how much condensate can flow, which is why it isn’t used to specify line sizes. Some contexts do use outside dimensions for other types of tubing, but for condensate drainage, standard practice is to specify the size by inside diameter, such as 3/4 inch or 1 inch. Hence, inside diameter is the appropriate dimension to specify condensate line sizes.

Sizing condensate lines is about the interior bore that carries the water. The amount of condensate that can drain relies on the cross-sectional area inside the pipe, so the inside diameter directly determines the flow capacity and ensures fittings, slopes, and traps align correctly. The outside diameter varies with material and wall thickness and does not reflect how much condensate can flow, which is why it isn’t used to specify line sizes. Some contexts do use outside dimensions for other types of tubing, but for condensate drainage, standard practice is to specify the size by inside diameter, such as 3/4 inch or 1 inch. Hence, inside diameter is the appropriate dimension to specify condensate line sizes.