46 C.F.R. §§ 34.25-5–34.25-20

The capacity and arrangement shall be such as to effectively blanket the entire area of the space protected. The rate of discharge and the arrangement of piping and spray nozzles shall be such as to give a uniform distribution over the entire area protected.

The spacing of the spray nozzles shall be on the basis of the spray pattern provided by the lowest pressure at any spray nozzle in the system. In no instance shall a system be designed for any spray nozzle to be operated at a pressure less than that for which it was approved. The maximum permissible height of the spray nozzle above the protected area shall not exceed that specified in its approval. Whenever there are obstructions to coverage by the spray patterns, additional spray nozzles shall be installed to provide full coverage.

The water supply shall be from outside the space protected and shall in no way be dependent upon power from the space protected. The pump supplying water for the system shall either be reserved exclusively for the system or it may be one of the fire pumps, provided the capacity of the fire pump as set forth in subpart 34.10 is increased by the required capacity of the system, so that this system may be operated simultaneously with the fire main system.

There shall be one control valve for the operation of the system located in an accessible position outside the space protected. The control shall be located as convenient as practicable to one of the main escapes from the space protected, and shall be marked as required by § 35.40-18 of this subchapter. It shall not be necessary to start the pumps from the control space.

Complete, but simple instructions for the operation of the system shall be located in a conspicuous place at or near the controls.

The valve to the space protected shall be marked as required by § 35.40-18 of this subchapter.

All piping, valves and fittings shall meet the applicable requirements of subchapter F (Marine Engineering) of this chapter.

Distribution piping shall be of materials resistant to corrosion, except that steel or iron pipe may be used if inside corrosion resistant coatings which will not flake off and clog the nozzles are applied. Materials readily rendered ineffective by heat of a fire shall not be used. The piping shall be subject to approval for each installation.

All piping, valves, and fittings shall be securely supported, and where necessary, protected against injury.

Drains, strainers, and dirt traps shall be fitted where necessary to prevent the accumulation of dirt or moisture.

Threaded joints shall be metal to metal, with no thread compound used.

Distribution piping shall be used for no other purpose.

All piping shall be thoroughly cleaned and flushed before installation of the water spray nozzles.

Spray nozzles shall be of an approved type.