(a) This subpart contains requirements for fluid power transmission and control systems and appurtenances. Except as otherwise provided for in this section, these requirements are applicable to fluid power and control systems where installed for the following equipment:

(1) Steering apparatus, main and auxiliary, including bow thruster systems.

(2) Cargo hatch operating systems unless fitted with an alternate mechanical means of operation and approved by the Commandant as hydraulically or pneumatically fail-safe. A system is considered to be fail-safe if a component failure will result in a slow and controlled release of the loading so as not to endanger personnel.

(3) Watertight door operating system.

(4) Automatic propulsion boiler control systems.

(5) Starting systems for internal combustion engines used for main propulsion, auxiliary power, as the prime mover for any required emergency apparatus, or as the source of propulsion power in ship maneuvering thruster systems.

(6) Centralized control system of main propulsion and auxiliary machinery.

(7) Lifeboat handling equipment.

(8) Controllable pitch propeller system.

(9) Installations used to remotely control components of piping systems listed in § 56.01-10(c)(1) of this subchapter.

(10) All systems containing a pneumatic or hydropneumatic accumulator.

(11) Materials and/or personnel handling equipment systems, i.e., cranes, hydraulic elevators, etc., not approved by the Commandant as fail-safe as defined in paragraph (a)(2) of this section.

(12) Any fluid power or control system installed in the cargo area of pump rooms on a tank vessel, or in spaces in which cargo is handled on a liquefied flammable gas carrier.

(13) All pneumatic power and control systems having a maximum allowable working pressure in excess of 150 psig.

(14) Any other hydraulic or pneumatic system on board that, in the judgment of the Commandant, constitutes a hazard to the seaworthiness of the ship or the safety of personnel either in normal operation or in case of failure.

(b) Other fluid power and control systems do not have to comply with the detailed requirements of this subpart but must meet the requirements of § 58.30-50.

(a) The requirements of part 56 of this subchapter are also applicable to piping and fittings in fluid power and control systems listed in § 58.30-1, except as modified herein. The designer should consider the additional pressure due to hydraulic shock.

(b) The system must be so designed that proper functioning of any unit must not be affected by the back pressure in the system. The design must be such that malfunctioning of any unit in the system will not render any other connected or emergency system inoperative because of back pressure.

(c) Pneumatic systems with a maximum allowable working pressure in excess of 150 psi must be designed with a surge tank or other acceptable means of pulsation dampening.

(d) Each pneumatic system must minimize the entry of oil into the system and must drain the system of liquids.

(a) The requirements of this section are applicable to all fluid power transmission and control systems installed on vessels subject to inspection.

(b) The fluid used in hydraulic power transmission systems must have a flashpoint of not less than 200 °F for pressures below 150 psig and 315 °F for pressures 150 psig and above, as determined by ASTM D92 (incorporated by reference, see § 58.03-1), Cleveland “Open Cup” test method.

(c) The chemical and physical properties of the hydraulic fluid must be suitable for use with any materials in the system or components thereof.

(d) The hydraulic fluid must be suitable for operation of the hydraulic system through the entire temperature range to which it may be subjected in service.

(e) The recommendations of the system component manufacturers must be considered in the selection and use of hydraulic fluid.

(a) The requirements of this section are applicable to those hydraulic and pneumatic systems listed in § 58.30-1.

(b) Materials used in the manufacture of tubing, pipes, valves, flanges, and fittings must be selected from those specifications that appear in table 1 to § 56.60-1 or table 1 to § 56.60-2; or they may be selected from the material specifications of Section I or Section VIII of the ASME BPVC (both incorporated by reference; see § 58.03-1). Materials designated by other specifications must be evaluated on the basis of physical and chemical properties. To assure these properties, the specifications must specify and require such physical and chemical testing as considered necessary by the Commandant. All tubing and pipe materials must be suitable for handling the hydraulic fluid used and must be of such chemical and physical properties as to remain ductile at the lowest operating temperature.

(c) Bolting must meet the requirements of § 56.25-20 of this subchapter except that regular hexagon bolts conforming to SAE J429, grades 2 through 8 (incorporated by reference, see § 58.03-1), or ASTM A193 (incorporated by reference, see § 58.03-1) may be used in sizes not exceeding 1.5 inches.

(d) The maximum allowable working pressure and minimum thickness must be calculated as required by § 56.07-10(e) of this subchapter.

(e) All flared, flareless and compression type joints must be in accordance with § 56.30-25 of this subchapter.

(f) Fluid power motors and pumps installed on vessels subject to inspection must be certified by the manufacturer as suitable for the intended use. Such suitability must be demonstrated by operational tests conducted aboard the vessel which must be witnessed by a marine inspector.

(a) The requirements of this section are applicable to those hydraulic and pneumatic systems listed in § 58.30-1.

(b) Hose and fittings must meet the requirements of subpart 56.60 of this subchapter.

(c) Hose assemblies may be installed between two points of relative motion but must not be subjected to torsional deflection (twisting) under any conditions of operation and must be limited, in general, to reasonable lengths required for flexibility. Special consideration may be given to the use of longer lengths of flexible hose where required for proper operation of machinery and components in the hydraulic system.

(d) Sharp bends in hoses must be avoided.

(a) An accumulator is an unfired pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic fluid. Accumulators must meet the applicable requirements in part 54 of this subchapter.

(b) If the accumulator is of the gas and fluid type, suitable separators must be provided between the two media, if their mixture would be dangerous, or would result in contamination of the hydraulic fluid and loss of gas through absorption.

(c) Each accumulator which may be isolated, must be protected on the gas and fluid sides by relief valves set to relieve at pressures not exceeding the maximum allowable working pressures. When an accumulator forms an integral part of systems having relief valves, the accumulator need not have individual relief valves.

(a) The requirements of this section are applicable to those hydraulic and pneumatic systems listed in § 58.30-1 and to all pneumatic power transmission systems.

(b) Fluid power cylinders consisting of a container and a movable piston rod extending through the containment vessel, not storing energy but converting a pressure to work, are not considered to be pressure vessels and need not be constructed under the provisions of part 54 of this subchapter.

(c) Cylinders must be designed for a bursting pressure of not less than 4 times the maximum allowable working pressure. Drawings and calculations or a certified burst test report must be submitted to show compliance with this requirement.

(d) Piston rods, except steering gear rams, must be either of corrosion resistant material or of steel protected by a plating system acceptable to the Commandant.

(e) Materials selection must be in accordance with the requirements of § 58.30-15(b).

(a) All fluid power and control systems and components thereof must be tested as required by this section.

(b) Accumulators constructed as pressure vessels under the provisions of part 54 of this subchapter must be tested and retested as required by parts 54 and 61 of this subchapter.

(c) Fluid power and control systems and piping assemblies must be given an installation test as follows:

(1) Fluid power and control systems and piping assemblies and associated equipment components, including hydraulic steering gear, in lieu of being tested at the time of installation, may be shop tested by the manufacturer to 1.5 times the maximum allowable pressure of the system. The required test pressure must be maintained for a sufficient amount of time to check all components for strength and porosity and to permit an inspection to be made of all connections.

(2) Fluid power and control systems and associated hydraulic equipment components which have been tested in conformance with paragraph (c)(1) of this section and so certified by the manufacturer, may be tested after installation as a complete assembly by stalling the driven unit in a safe and satisfactory manner and by blowing the relief valves. Otherwise, these systems must be hydrostatically tested in the presence of a marine inspector at a pressure of 1.5 times the maximum allowable pressure.

(3) Fluid power and control systems incorporating hydropneumatic accumulators containing rupture discs may be tested at the maximum allowable working pressure of the system in lieu of 1.5 times this value as prescribed in paragraphs (c)(1) and (2) of this section provided the accumulators have been previously tested in accordance with paragraph (b) of this section and welded or brazed piping joints are not employed in the system. If welded or brazed joints are employed, the system must be tested in accordance with the requirements of paragraphs (c)(1) and (2) of this section except that the accumulators may be isolated from the remainder of the system.

(d) Fluid power and control systems must be purged with an inert gas or with the working fluid and all trapped air bled from the system prior to any shipboard testing.

(e) Fluid control systems, such as boiler combustion controls, containing components with internal parts, such as bellows or other sensing elements, which would be damaged by the test pressure prescribed in paragraphs (c)(1) and (2) of this section may be tested at the maximum allowable working pressure of the system. In addition, all fluid control systems may be tested using the system working fluid.

(a) Diagrammatic plans and lists of materials must be submitted for each of the fluid power and control systems listed in § 58.30-1(a) that is installed on the vessel. Plan submission must be in accordance with subpart 50.20 of this subchapter and must include the following:

(1) The purpose of the system.

(2) Its location on the vessel.

(3) The maximum allowable working pressure.

(4) The fluid used in the system.

(5) Details of the system components in accordance with § 56.01-10(d) of this subchapter.

(b) [Reserved]

(a) All fluid power and control systems installed on a vessel, except those listed in § 58.30-1(a), must meet the following requirements:

(1) Diagrams of the system providing the information required by § 58.30-40(a)(1) through (4) must be submitted. These are not approved but are needed for records and for evaluation of the system in accordance with § 58.30-1(a)(14).

(2) The hydraulic fluid used in the system must comply with § 58.30-10.

(3) The installed system must be tested in accordance with § 58.30-35(c)(2).

(4) All pneumatic cylinders must comply with § 58.30-30.

(5) Additional plans may be required for “fail-safe” equipment and for cargo hatch systems with alternate means of operation.

(b) [Reserved]