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Sprinkler and Water Mist Extinguishing Systems





APPROVAL GUIDANCE & INFORMATION:  Water spray nozzles approved under this category are intended for installation in the pump rooms of domestic tankers in accordance with 46 CFR 34.25.  The type approval denotes the location and spacing of the spray nozzles in accordance with approved drawings.

This approval category is based on testing the water spray nozzles to a unique fire test in a 30-foot by 30-foot test room with two simulated gratings that act as obstructions.  Because of the limited application for this approval category, anyone desiring an approval of water spray nozzles in this category should first contact this office (CG-ENG-4) to discuss the testing and approval of the system.

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APPROVAL GUIDANCE & INFORMATION:  Water mist systems are approved for installation on U.S. Flag ships as a substitute for automatic sprinklers in accommodation and service areas and control stations, and as a substitute for total flooding fixed gas systems in machinery spaces and cargo pump rooms.  The testing requirements for the water mist equipment are contained in the following test protocols:

Protected Area Test Protocol Type of System
Accommodation and service areas and control stations IMO Res. A 800 (19) Area-wide protection
Machinery spaces of Category A and
cargo pump rooms
MSC/Circ. 1165 Area-wide protection
Machinery spaces of Category A MSC/Circ. 913 Fixed local application

Water mist systems must be tested to the above guidelines at a Coast Guard accepted independent testing laboratory to receive a type approval. The IMO fire test protocols require both component testing and fire testing of the water mist nozzles.  The fire testing must be conducted in mock-up spaces of the maximum size requested for approval.  Not all of the Coast Guard accepted laboratories have fire testing facilities that are suitable for approvals for very large spaces.  In that case, the component testing may be done at the accepted laboratory while the fire testing is conducted at another facility, and the accepted laboratory participates in the planning and conduct of the fire testing program.

Each approved system is required to have a marine design, installation, operation and maintenance manual (DIOM) that is evaluated as part of the type approval.   The manual must include as a minimum:

  1. A detailed technical description of the system.

  2. A description of the allowable types of hazards that can be protected by the system.

  3. System design limitations and dimensioning criteria, such as the maximum area that can be protected, nozzle spacing, maximum ceiling height, minimum required water supplies, etc.

  4. Detailed description and drawing of each system component, including material specifications and performance data.

  5. A typical marine system design and layout along with supporting design calculations.

  6. Engineering data, such as hydraulic flow / pressure curves, friction loss in fittings, etc.

  7. Required types of piping and fittings that must be used on vessels, including approved details for the shipyard installation of piping and fittings.

  8. Installation, operation, testing, maintenance, and recharge instructions.

  9. Piping flushing and hydrostatic testing instructions.

  10. Description of system interface with electrical components such as tamper switches and water flow alarms.

The system manual should contain complete information on the design and installation of the system for the equipment as-tested.  The system water supply pumps, controls valves and pressure vessels may be included in the laboratory testing program; alternatively, the components should be recognized by a classification society as meeting U.S. Coast Guard Marine Engineering regulations.  The manual should also include drawings of key components such as nozzles, valves, filters, strainers, etc.  A sample design for each application should be included that allows an understanding of the dimensioning requirements and nozzle spacing for each type of protected space.

ACCEPTED INDEPENDENT LABORATORIES:  Underwriters Laboratories Inc., Factory Mutual, and Underwriters Laboratories of Canada are recognized as independent testing laboratories for type approval testing of water mist systems. 

SUBMITTAL PACKAGE:  Please submit the following information in the Submittal Package:

Please send the Submittal Package and other related information to the following address:

Commandant (CG-ENG-4)
U.S. Coast Guard Stop 7509
2703 Martin Luther King Ave Jr SE
Washington, DC 20593-7509

Once the equipment has been approved by this office, it will receive Coast Guard Type Approval and a Certificate of Approval (COA).  The COA will be issued for 5 years and will remain valid during that time period if the product meets the testing of the Quality Control Program.

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APPROVAL GUIDANCE & INFORMATION:  Conventional sprinkler systems and related equipment required by 46 CFR 34.30, 46 CFR 76.05, 46 CFR 76.25, 46 CFR 95.30, 46 CFR 108.430, 46 CFR 116.440 (c), 46 CFR 118.400 (g), 46 CFR 181.400, SOLAS Regulations II-2/10.6 and the FSS Code Chapter 8 do not require type approval by the Coast Guard.

The above cited regulations require the system to be designed and installed in compliance with the marine section of NFPA 13-1996.  (If the vessel is required to have a SOLAS certificate, SOLAS Regulations II-2/10.6 and the FSS Code Chapter 8 may require specific features or water application rates that exceed those in NFPA 13.)

Sprinkler system components approved for use in shore side buildings have been determined acceptable for the protection of accommodation and service spaces on ships and marine facilities without further specialized approval testing. The standard laboratory approval testing procedure for sprinkler heads includes adequate corrosion and vibration testing elements.

Typical marine sprinkler systems consist of a sprinkler pump, a fresh water storage tank, an air compressor or other source to pressurize the fresh water tank, system piping and valves, alarms and automatic sprinkler heads. The piping and fittings used in automatic sprinkler systems are basic components that are covered by Subchapter F, Marine Engineering.  NFPA 13 requires automatic sprinkler heads and related sprinkler system components to be tested by an independent laboratory.  The Coast Guard accepts Underwriters Laboratories, Inc. (UL) listing or Factory Mutual (FM) approval of the components as meeting this requirement.

ACCEPTABLE INDEPENDENT LABORATORIES:  Underwriters Laboratories Inc., Factory Mutual and Underwriters Laboratories of Canada.

SUBMITTAL PACKAGE:  Questions regarding application for approval should be made directly to Underwriters Laboratories, Inc. (UL) listing or Factory Mutual (FM).

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Last Modified 1/12/2016