Unique Considerations. In piping design, consider
fuel characteristics as they may be affected by the sea water
temperature, particularly in cold water. For diesel fuel,
aviation turbine fuel, or other light fuels, small individual
lines are preferable as follows:
a) Minimum nominal pipe size of 6 inches (150 mm).
b) For transfers of fuels exceeding 3,000 gpm (189
L/s), use 12-inch (300 mm) to 16-inch (400 mm) diameter pipe.
c) Instead of pipes larger than 16 inches (400 mm)
in diameter, consider using two smaller pipes.
d) At an accessible upland location, as close to the
water entry as practical, provide a double block and bleed
valve and a manually operated check valve or bypass to allow
reversal of flow when required.
between the vessel in the offshore berth and the shore
Corrosion Protection. Wrap, coat, and cathodically
protect underwater pipelines in accordance with Section 2 of
Depth of Burial. Provide sufficient burial depth of
underwater pipelines to prevent damage by dredging of the
waterway, by ships' anchors, trawls, or by scouring action of
the current. Specifically, ensure depth conforms to the
requirements of 49 CFR 195. Where lines cross ship channels
or anchorages, ensure the top of the pipe is at least 12 feet
(3.7 m) below the theoretical, present or planned future
bottom elevation, whichever is deeper. Recommended backfill
in such areas is 2 feet (0.6 m) of gravel directly over the
pipe, followed by stones weighing 50 to 60 pounds (23 kg to 27
kg) up to the bottom elevation.
Pipe Thickness and Weight. Provide sufficient pipe
wall thickness to keep stresses due to maximum operating
pressure and other design loads within design limits. Include
full consideration to extra stresses which may occur in laying
the pipe. It is common practice to use heavier wall pipe for
water crossings of more than 200 feet (60 m) from bank to bank