(a) Standards. The design, construction, workmanship and tests of gas turbines and their associated machinery must be at least equivalent to the standards of the ABS Marine Vessel Rules (incorporated by reference, see § 58.03-1).

(b) Materials. The materials used for gas turbine installations must have properties suitable for the intended service. When materials not conforming to standard ASTM specifications are employed, data concerning their properties, including high temperature strength data, where applicable, must be furnished.

(c) Exhausts. (1) Where piping is used for gas turbine exhaust lines, Class II is required as a minimum. (See subpart 56.04 of this subchapter.) Where the exhaust pressure exceeds 150 psig, such as in closed cycle systems, Class I must be used. Where ducting other than pipe is employed, the drawings and design data must be submitted to substantiate suitability and safety for the intended service.

(2) Where considered necessary, gas turbines and associated exhaust systems must be suitably insulated or cooled, by means of lagging, water spray, or a combination thereof.

(3) Gas turbine exhausts must not be interconnected with boiler uptakes except for gas turbines used for emergency power and lighting or for emergency propulsion. Dampers or other suitable means must be installed to prevent backflow of boiler exhaust gases through the turbine. Interconnected exhausts must be specifically approved by the Commandant.

(4) A gas turbine exhaust on a mobile offshore drilling unit must not discharge in a classified location. (See note 1 to this section.)

(d) Air inlets. Air inlets must be designed as follows:

(1) Each air inlet must have means to protect the safety of life and to prevent the entrance of harmful foreign material, including water, into the system.

(2) A gas turbine air inlet must not be in a classified location. (See note 1 to this section.)

(e) Cooling and ventilation. Means must be provided for circulating air, either natural or forced, through the engine compartment for cooling and ventilation.

(f) Automatic shutdown. (1) The control system must be designed for automatic shutdown of the engine with actuation of audible and visible alarms at shutdown. The visible malfunction indicator must indicate what condition caused the shutdown and remain visible until reset. Automatic shutdown must occur under the following conditions:

(i) Overspeed.

(ii) Low lubricating oil pressure. Consideration will be given providing alarm only (without shutdown) in those cases where suitable antifriction bearings are fitted.

(2) Audible or visible alarms must also be provided for:

(i) Excessive gas temperature, measured at the turbine inlet, gas generator, interstage turbine or turbine exhaust.

(ii) Excessive lubricating oil temperature.

(iii) Excessive speed.

(iv) Reduced lubricating oil pressure.

(3) A remote, manually operated shutdown device must be provided. Such device may be totally mechanical or may be electrical with a manually actuated switch.

(g) Drawings and design data. Drawings and design data of the following components must be submitted to substantiate their suitability and safety for the service intended:

(1) Combustion chamber.

(2) Regenerator or recuperator.

(3) Casing or piping conveying the gas from the combustion device to the gas turbine.

(h) Fuel systems. Gas turbine fuel systems must meet the requirements of part 56 of this subchapter.

(i) Fire extinguishing systems. A special local fire extinguishing system may be required for gas turbine installations if considered necessary by the Commandant. Such a system would be in addition to any other required in the compartment in which the gas turbine is located.

Note 1 to § 58.10-15:

Sections 108.171 to 108.175 of this chapter define classified locations for mobile offshore drilling units.