6.1.1 The design,
construction and operational capability of valves is to be in accordance
with an acceptable National or International Standard appropriate
to the piping system. Where valves are not in accordance with an acceptable
standard, details are to be submitted for consideration. Where valves
are fitted, the requirements ofPt 5, Ch 10, 6.1 Design requirements 6.1.2 are to be satisfied.
6.1.2 Valves
are to be made of steel, cast iron, copper alloy, or other approved
material suitable for the intended purpose.
6.1.3 Valves
having isolation or sealing components sensitive to heat are not to
be used in spaces where leakage or failure caused by fire could result
in fire spread, flooding or the loss of an essential service.
6.1.4 Where
valves are required to be capable of being closed remotely in the
event of fire, the valves, including their controlgear, are to be
of steel construction or of an acceptable fire tested design.
6.1.5 Valves
are to be arranged for clockwise closing and are to be provided with
indicators showing whether they are open or shut unless this is readily
obvious.
6.1.6 Valves
and cocks are to be fitted with legible nameplates, and, unless otherwise
specifically mentioned in the Rules the valves and cocks are to be
fitted in places where they are at all times readily accessible.
6.1.7 Valves
are to be so constructed as to prevent the possibility of valve covers
or glands being slackened back or loosened when the valves are operated.
6.1.8 Valves
are to be used within their specified pressure and temperature rating
for all normal operating conditions, and are to be suitable for the
intended purpose.
6.1.9 Valves
intended for submerged installation are to be suitable for both internal
and external media. Spindle sealing is to prevent ingress of external
media at the maximum external pressure head expected in service.
6.1.10 The
controls of butterfly and ball valves of the "swing through type"
are to be provided with suitable means (such as a gearbox) to prevent
this.
6.1.13 Where
the valves are of the diaphragm type, they are not acceptable as shut-off
valves at the shell plating.
6.1.14 Resiliently
seated valves are not to be used in main or auxiliary machinery spaces
as branch or direct bilge suction valves or as pump suction valves
from the main bilge line. For exemptions of the above, resiliently
seated valves may be accepted in positions indicated below, and subject
to the following conditions:
-
As pump suction
valve from the main bilge line where the valve is located in the immediate
vicinity of the pump and in series with a metal seated non-return
valve. The non-return valve is to be fitted on the bilge main side
of the resiliently seated valve.
-
As branch suction
valve where the branch is connected to a non-isolated bilge main,
as per Pt 5, Ch 11, 4.3 Branch bilge suction arrangements connected to non-isolated bilge main, and in series
with a metal seated non-return valve. The non-return valve is to be
fitted at the branch side of the resiliently seated valve.
-
When they are used
in other locations and within auxiliary machinery spaces having little
or no fire risk, they should be of an approved fire safe type and
used in conjunction with a metal seated non-return valve.
6.1.15 Resiliently
seated valves are not acceptable for use in the fire water mains unless
they have been satisfactorily fire tested.