封ふう水すい

noun

water seal; sealing water

Technical term used in plumbing, engineering, and similar fields to refer to water that forms a seal to prevent gas or odor from passing through.

• 排はい水すい管かんの封ふう水すいが蒸じょう発はつすると、悪あく臭しゅうが上あがってくることがある。

  If the water seal in the drain pipe evaporates, bad odors can sometimes rise up.