2 Definitions
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1315 – Guidelines for the Approval of Fixed Dry Chemical Powder Fire-Extinguishing Systems for the Protection of Ships Carrying Liquefied Gases in Bulk – (10 June 2009) - Annex – Guidelines for the Approval of Fixed Dry Chemical Powder Fire-Extinguishing Systems for the Protection of Ships Carrying Liquefied Gases in Bulk - 2 Definitions

2 Definitions

  2.1 Caking is a chemical reaction between dry chemical powder and moisture that causes individual particles of the medium to bind together to form an aggregate mass.

  2.2 Dry chemical powder is an extinguishing medium consisting of very fine particles of sodium or potassium bicarbonate treated or supplemented with additional materials to prevent packing and caking (moisture absorption) and to ensure consistent flow characteristics.

  2.3 Dry chemical powder unit is a complete system including dry chemical storage container(s), pressurizing gas storage container(s), controls, piping and hand hose lines.

  2.4 Gas point is a defined point in the discharge of a dry chemical powder unit when the discharge of dry chemical powder ends, and is marked by a change in the nozzle stream to the discharge of primarily pressurizing gas.

  2.5 Hand hose line is a hand-held dry chemical powder nozzle covering cargo areas not covered by a monitor.

  2.6 Monitor is a fixed dry chemical powder nozzle protecting cargo loading and discharge manifold areas.

  2.7 Packing is a phenomenon that occurs when dry chemical powder stored in a container is subjected to vibration causing the smaller particles to move to the bottom of the container and the larger particles to travel to the top.

  2.8 Pressurizing medium is the gas used to expel the dry chemical from the system, usually dry nitrogen.


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