(a) Common vapor headers for polymerizing cargoes must be constructed with adequate means to permit internal examination of vent headers.
(b) Vapor piping systems and pressure-vacuum valves that are used for polymerizing cargoes must be inspected internally at least annually.
(c) Pressure-vacuum valves and spill valves which are used for polymerizing cargoes must be tested for proper movement prior to each transfer.
source: USCG-1999-5150, 78 FR 42642, July 16, 2013, unless otherwise noted.
cite as: 46 CFR 39.2014