- Pipe supports shall be designed to provide adequate lateral, longitudinal, and vertical sway bracing.
- The design shall account for the degree of bracing, which varies with the route and operation of the vessel.
- Bracing shall be designed to ensure the following:
- Pipe supports shall be welded to the structure.
- Hangers that can loosen during ship motion or vibration, such as screw-down-type hangers, shall not be permitted.
- Hangers that are listed for seismic use shall be permitted to be used in accordance with their listing.
- Vessels shall have two spare detection devices or fusible elements when operating voyages are normally less than 24 hours.
- Vessels shall have four spare detection devices or fusible elements when operating voyages are normally more than 24 hours.
- Piping shall be of non-heat-sensitive type from the sea suction up through the penetration of the last A-Class barrier enclosing the space(s) in which the heat-sensitive piping is installed.
- B-Class draft stops shall be fitted not more than 45 ft (14 m) apart between the marine thermal barrier (see definitions in Chapter 3 and 30.1.3) and the deck or shell.
- Portions of a system that are constructed from heat-sensitive materials shall be installed behind a marine thermal barrier, unless the provisions of item (4) are met.
- *Piping materials with brazed joints shall not be required to be installed behind a marine thermal barrier, provided the following conditions are met:
- The system is of the wet pipe type.
- The piping is not located in spaces containing boilers, internal combustion engines, or piping containing flammable or combustible liquids or gases under pressure, cargo holds, or vehicle decks.
- A relief valve in compliance with 8.1.2 is installed in each section of piping that is capable of being isolated by a valve(s).
- A valve(s) isolating the section of piping from the remainder of the system is installed in accordance with 220.127.116.11 and 18.104.22.168.
- The tank shall contain a standing charge of freshwater equal to that specified by Table 22.214.171.124.
- The pressure tank shall be sized in accordance with 5.2.4.
- A glass gauge shall be provided to indicate the correct level of water within the pressure tank.
- Arrangements shall be provided for maintaining an air pressure in the tank such that, while the standing charge of water is being expended, the pressure will not be less than that necessary to provide the design pressure and flow of the hydraulically most remote design area.
- Suitable means of replenishing the air under pressure and the freshwater standing charge in the tank shall be provided.
- Tank construction shall be in accordance with the applicable requirements of 46 CFR, Subchapter F, "Marine Engineering."
|System Type||Additional Water Volume|
Wet pipe system
Flow requirement of the hydraulically most remote system demand for 1 minute
Flow requirement of the hydraulically most remote system demand for 1 minute of system demand plus the volume needed to fill all dry piping
- The pump is listed for marine use and is sized to meet the required system demand.
- The suction for the fire pump is located below the suction for the freshwater system so that there shall be a minimum water supply of at least 1 minute for the required system demand.
- Pressure switches are provided in the system and the controller for the pump that automatically start the pump within 10 seconds after detection of a pressure drop of more than 5 percent.
- There shall be a reduced pressure zone backflow preventer to prevent contamination of the potable water system by saltwater.
- This pump has at least two sources of power. Where the sources of power are electrical, these shall be a main generator and an emergency source of power. One supply shall be taken from the main switchboard, by separate feeder reserved solely for that purpose. This feeder shall be run to an automatic changeover switch situated near the sprinkler unit, and the switch shall normally be kept closed to the feeder from the emergency switchboard. The changeover switch shall be clearly labeled, and no other switch shall be permitted in these feeders.
- * Pump controls and system sensors shall be arranged such that the secondary pump will automatically operate if the primary pump fails to operate or deliver the required water pressure and flow. [Figure A.126.96.36.199.2(1) is an example of an acceptable dual pump arrangement.]
- Both pumps shall be served from normal and emergency power sources. However, where approved by the authority having jurisdiction, the secondary pump shall be permitted to be nonelectrically driven.
- Pump failure or operation shall be indicated at the central safety station.
- The pump is adequately sized to meet the required fire hose and sprinkler system pressure and flow demands simultaneously.
- The fire main system is segregated from the sprinkler system by a normally closed valve that is designed to automatically open upon failure of the designated fire pump.
- The fire pump that supplies the fire main is automatically started in the event of dedicated fire pump failure or loss of pressure in the sprinkler main. (See Figure A.188.8.131.52.)