6.1 Materials used for piping should be steel
or as follows:
-
.1 where located above a 15 minute-rated fire
resisting ceiling and comprising either a dry or combination pipe
system associated with a fire detection system, or a wet pipe system:
-
.1.1 materials complying with requirements of
Level 3 under resolution A.753(18) on
Guidelines for the Application of Plastic Pipes on Ship; or
-
.1.2 metals other than steel, having properties
of good conduction of heat, such as aluminium or copper;
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.2 other dry pipe systems and systems not continuously
filled with water; materials complying with the requirements of Level
2 of A.753(18).
6.2 Piping should be secured to the craft's structure
using engineering practices that account for both static and dynamic
loads imposed by swaying pipe, the moving craft and moving fluid inside
the pipe.
6.3 The means for fastening the sprinkler piping
to the structure of the craft and should be suitable for use in the
marine environment. Pipe hangers incorporating threaded fasteners
should provide a means for the fasteners to remain secure while subjected
to vibration from the craft.
6.4 The means of connecting the pipe system to
the structure of the craft and piping connections should taken into
account the long-term properties of the material and the interactions
of all the materials used in the means of connection with due regard
to preventing corrosion by contact between dissimilar metals.
6.5 Friction loss calculations should utilise
the Hazen-Williams formula. Calculation of flows in carbon steel piping,
including galvanised piping, should be based on C = 100. Calculations
for flows in wet pipe sprinkler systems employing carbon steel piping
should be based on C = 120. For all systems, flow calculations for
corrosion resistant piping such as copper, copper alloys, stainless
steel and plastic piping should be based on C = 150.