5. Piping Design, Treatment and Installation
This chapter provides general guidelines for the design, construction and planning of piping systems,
however, not excluding other solutions of at least equal standard. Installation related instructions are included
in the project specific instructions delivered for each installation.
Fuel, lubricating oil, fresh water and compressed air piping is usually made in seamless carbon steel (DIN
2448) and seamless precision tubes in carbon or stainless steel (DIN 2391), exhaust gas piping in welded
pipes of corten or carbon steel (DIN 2458). Sea-water piping should be in Cunifer or hot dip galvanized
steel.
Gas piping between Gas Valve Unit and the engine is to be made of stainless steel.
NOTE! The pipes in the freshwater side of the cooling water system must not be galvanized!
Attention must be paid to fire risk aspects. Fuel supply and return lines shall be designed so that they can
be fitted without tension. Flexible hoses must have an approval from the classification society. If flexible
hoses are used in the compressed air system, a purge valve shall be fitted in front of the hose(s).
It is recommended to make a fitting order plan prior to construction.
The following aspects shall be taken into consideration:
• Pockets shall be avoided. When not possible, drain plugs and air vents shall be installed
• Leak fuel drain pipes shall have continuous slope
• Vent pipes shall be continuously rising
• Flanged connections shall be used, cutting ring joints for precision tubes
• Flanged connections shall be used in fuel oil, lubricating oil, compressed air and fresh water piping
• Welded connections (TIG) must be used in gas fuel piping as far as practicable, but flanged connections
can be used where deemed necessary
Maintenance access and dismounting space of valves, coolers and other devices shall be taken into con-
sideration. Flange connections and other joints shall be located so that dismounting of the equipment can
be made with reasonable effort.
5.1 Pipe dimensions
When selecting the pipe dimensions, take into account:
• The pipe material and its resistance to corrosion/erosion.
• Allowed pressure loss in the circuit vs delivery head of the pump.
• Required net positive suction head (NPSH) for pumps (suction lines).
• In small pipe sizes the max acceptable velocity is usually somewhat lower than in large pipes of equal
length.
• The flow velocity should not be below 1 m/s in sea water piping due to increased risk of fouling and
pitting.
• In open circuits the velocity in the suction pipe is typically about 2/3 of the velocity in the delivery
pipe.
Product Guide Wärtsilä 34DF - 3/2012 29
Product Guide
5. Piping Design, Treatment and Installation
To Next Page
Loading...
Need help?
General