Protectoseal Series No. 17800, Pipe-Away Pressure Conservation Vent, is intended for use where pressure relief is required and the relieving vapors must be piped away and not emitted into the atmosphere. May also be used for vacuum relief. A pallet in the vent housing opens and closes permitting relief necessary to avoid tank damage. A flanged side connection is provided for easy pipe-away of vapors eliminating the emission of vapors to the atmosphere.