Definition(s)
Liquid Seal or Water Seal
Device that directs the flow of relief gases through a liquid (normally water) on the path to the flare burner, used to protect the flare header from air infiltration or flashback, to divert flow, or to create back pressure for the flare header.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global Standards