Product Manual

Appendix A. Diesel Fuel Piping 2-2017

A.0 Diesel Fuel Piping Requirements

• Diesel fuel lines should be constructed from black iron pipe. Cast iron

and aluminum pipe and fittings must not be used because they are

porous and can leak fuel. Galvanized fuel lines, fittings, and tanks

must not be used because the galvanized coating is attacked by the

sulfuric acid that forms when the sulfur in the fuel combines with tank

condensate, resulting in debris that can clog fuel pumps and filters.

Copper lines should not be used because fuel polymerizes (thickens)

in copper tubing during long periods of disuse and can clog fuel

injectors. Also, copper lines are less rugged than black iron, and thus

more susceptible to damage.

NOTICE

Never use galvanized or copper fuel lines, fittings or fuel tanks.

Condensation in the tank and lines combines with the sulfur in

the diesel fuel to produce sulfuric acid. The molecular structure

of the copper or galvanized lines or tanks reacts with the acid

and contaminates the fuel.

• Approved flexible fuel hose must be used for connections at the

engine to take up generator set movement and vibration.

• Piping from a day tank to the engine should run “downhill" all the way

from the tank to the engine, with no overhead loops that can allow air

to be entrained in the system.

• Fuel system piping should be properly supported to prevent vibration

and breakage due to vibration. The piping should not run close to

heating pipes, electrical wiring, or engine exhaust system

components. The piping system design should include valves at

appropriate locations to allow isolation of system components for

repair without draining the entire fuel system.

• Piping systems should be regularly inspected for leaks and general

condition. The piping system should be flushed before operation of

the engine to remove dirt and other impurities that could damage the

engine. Use of plugged “T" connections rather than elbows allows for

easier cleaning of the piping system.

• The engine manufacturer's data indicates the maximum fuel inlet and

return restrictions, the maximum fuel flow, supply and return, and the

fuel consumption. The table below indicates minimum hose and pipe

sizes for connections to a supply tank or day tank when it is within 50

feet (15 meters) of the set and at approximately the same elevation.

Hose and pipe size should be based on the maximum fuel flow rather

than on the fuel consumption. It is highly recommended that the fuel inlet

and return restrictions be checked before the generator set is placed in

service.