CFR > Title 33 - Navigation and Navigable Waters > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER O—POLLUTION (parts 151 to 159) > PART 157—RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK > SUBPART D—Crude Oil Washing (COW) System on Tank Vessels (§157.100 to §157.172) > 157.122—Piping, valves, and fittings.

157.122—Piping, valves, and fittings.

(a) Except as allowed in paragraph (o) of this section, the piping, valves, and fittings of each COW system must:
(1) Meet 46 CFR Part 56; and
(2) Be of steel or an equivalent material accepted by the Commandant.
(b) The piping of each COW system must be permanently installed.
(c) The piping of each COW system must be separate from other piping systems on the vessel, except that the vessel's cargo piping may be a part of the COW piping if the cargo piping meets this section.
(d) The piping of each COW system must have overpressure relief valves or other means accepted by the Commandant to prevent overpressure in the piping of the COW system, unless the maximum allowable working pressure of that system is greater than the shut-off head of each pump that meets § 157.126(b).
(e) Each overpressure relief valve must discharge into the suction side of a pump that meets § 157.126(b).
(f) The piping and equipment of a COW system may not be in machinery spaces.
(g) Each hydrant valve for water washing in the piping of a COW system must:
(1) Have adequate strength to meet 46 CFR Part 56 for the working pressure for which the system is designed; and
(2) Be capable of being blanked off.
(h) Each sensing instrument must have an isolating valve at its connection to the piping of the COW system, unless the opening to that connection is 0.055 inches (1.4 millimeters) or smaller.
(i) If the washing system for cargo tanks has a steam heater used when water washing, it must be located outside the engine room and must be capable of being isolated from the piping of the COW system by:
(1) At least two shut-off valves in the inlet piping and at least two shut-off valves in the outlet piping; or
(2) Blank flanges identifiable as being closed (e.g., spectacle flanges).
(j) If the COW system has a common piping system for oil washing and water washing, that piping system must be designed to drain the crude oil into a slop tank or a cargo tank.
(k) The piping of a COW system must be securely attached to the tank vessel's structure with pipe anchors.
(l) When COW machines are used as pipe anchors, there must be other means available for anchoring the piping if these machines are removed.
(m) There must be a means to allow movement of the COW system piping as a result of thermal expansion and flexing of the tank vessel.
(n) The supply piping attached to each deck mounted COW machine and each COW machine that is audio inspected under § 157.155(a)(4)(ii) must have a shut-off valve.
(o) On combination carriers, piping of the COW system installed between each COW machine located in a cargo tank hatch cover and an adjacent location just outside the hatch coaming, may be flexible hose with flanged connections that is acceptable by the Commandant.