Section
2 General
2.1 Documentation required for design review
2.1.1 A System Design Description indicating the following information is to be
submitted for each piping system:
Design pressure.
Design temperature.
Class of system.
Internal pipe diameter and thickness.
Material specification.
Corrosion protection.
Corrosion allowance.
Pipe connection specifications.
Valve specifications.
Flexible hose specifications.
Expansion piece specifications.
Details of any other pipe fittings.
Pumping unit type and discharge characteristics.
Testing procedures.
System Design Description for heat exchangers as required by Vol 2, Pt 7, Ch 1, 18.1 General 18.1.11.
2.1.2 Where the Owner has specified requirements for the life of a particular
piping system under defined operating conditions, details of enhanced pipe scantlings
and assumptions made are to be submitted for review.
2.1.3 Pipe flow calculations are to be submitted for all mobility and ship type piping
systems, together with validation reports as appropriate for the calculation method. The
responsibility for error free specification and input of program data and the subsequent
correct transposition of output rests with the designer.
2.2 Definitions
2.2.1
Mobility and/or Ship Type piping systems are those systems installed for the
propulsion and safety of the ship (see
Vol 2, Pt 1, Ch 1, 3 Engineering system designation) and include the following:
Air and overflow arrangements.
Sounding arrangements.
Bilge and dewatering systems.
Ballast systems.
Fuel oil systems.
Gas fuel systems.
Lubricating
oil systems.
Thermal oil systems.
Hydraulic
oil systems for:
- steering gears;
- controllable pitch propellers;
- thrust units for propulsion;
- windlass machinery;
- watertight bow, stern, side and
internal doors;
- valve control systems, etc.
Fresh water cooling systems for machinery.
Sea water
cooling systems.
Compressed air systems for starting engines,
control and alarms.
Steam and condensate systems.
Exhaust and flue gas systems.
Control systems for
remote operation of valves and ventilation flaps.
2.2.2
Ancillary piping systems are those systems installed for conditions of
habitability and recreation; they include the following:
Heating systems.
Air conditioning systems.
Domestic sanitary and fresh water systems.
2.2.3
Piping
system includes pipes and fittings such as expansion joints,
valves, pipe joints, support arrangements, flexible tube lengths etc.
and components in direct connection with the piping such as pumps,
heat exchangers, air receivers, independent tanks, etc. It does not
include main and auxiliary machinery such as oil engines, steam and
gas turbines, boilers, reduction gears, etc.
2.3 Classes of piping systems and
components
2.3.1 Pressure piping systems are divided into three classes for the purpose of
assigning appropriate testing requirements, types of joints to be adopted, heat
treatment and weld procedure.
Table 1.2.1 Classes of piping system
| Piping system
|
Class II
|
Class III
|
| P2
|
T2
|
P1
|
T1
|
|
|
bar
|
deg C
|
bar
|
deg C
|
| Steam
|
16,0
|
300
|
7,0
|
170
|
| Thermal
oil
|
16,0
|
300
|
7,0
|
150
|
| Flammable
liquids, see Note 1
|
16,0
|
150
|
7,0
|
60
|
| Other media,
see Note 2
|
40,0
|
300
|
16,0
|
200
|
Note
1. Flammable liquids include: fuel oil;
lubricating oil and flammable hydraulic oil.
Note
2. Including water, air, gases,
non-flammable hydraulic oil.
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2.3.2 Dependent on the service for which they are intended, Class II and Class
III piping are not to be used for design pressure or temperature conditions in excess of
those shown in Table 1.2.1 Classes of piping system. Where either the maximum design pressure or
temperature exceeds that applicable to Class II piping systems, Class I piping is to be
used. To illustrate, see
Figure 1.2.1 Classes of piping system.
Figure 1.2.1 Classes of piping system
2.3.3 In addition to the pressure piping systems in Table 1.2.1 Classes of piping system, Class III pipes may be used for open ended
piping, e.g. overflows, vents, boiler waste steam pipes, open ended drains, sounding
pipes, etc.
2.3.4 Class II and III pipes are not to be used for toxic media.
2.3.5 Class I pipes are generally required for corrosive media. Class II pipes may be used for
corrosive media where special safeguards for reducing the potential for leakage and
limiting its consequences are provided, e.g. the use of pipe ducts, shielding,
screening, etc. in such a way that a leakage will not cause a potential hazard or damage
to surrounding areas. Class III pipes are not to be used for corrosive media. Materials
used for piping for corrosive media are to be specially considered.
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