12 May 2003
Including change 1, 19 January 2007
to relieve strains resulting from differential movement unless the pipe is
shown to have sufficient stress capacity.
Flexible connections should be used between valves and lines for valve
installation on pipes 76 mm (3 in) or larger in diameter.
Flexibility should be provided by use of flexible joints or couplings on a
buried pipe passing through different soils with widely different degrees of
consolidation immediately adjacent to both sides of the surface separating
the different soils.
Flexibility should be provided by use of flexible joints or couplings at all
points that can be considered to act as anchors, at all points of abrupt
change in direction, and at all tees.
Piping containing hazardous materials should contain numerous shutoff
valves and check valves to minimize release of materials if there is a
break. Seismic shutoff valves should be used where necessary to control
a system or process. A secondary containment system should be
incorporated where feasible.
When piping is connected to equipment or tanks, use of braided flexible
hoses is preferable to bellow-type flexible connectors. Bellow-type flexible
connectors have been noted to fail from metal fatigue. Welded joints are
preferable to threaded or flanged joints. If flanged joints cannot be
avoided, the use of self-energizing or spiral wound gaskets can allow a
bolt to relax while continuing to provide a seal. (Reference: Association
of Bay Area Governments, 1990.)
Supports. Piers may contain pipelines for freshwater, saltwater, steam,
compressed air, waste oil, sewer, and fuels systems; and may also contain electrical
power and communication lines. Ship demands dictate the utility system configurations.
In general, design of these lines follows the general provisions discussed herein. It is
essential that the lines be attached to the supporting structure with sufficient rigidity that
the lines are restrained against independent movement. Attachments to a pier may be
analyzed as simple two-degree-of-freedom systems. Resonance amplification can
occur when the natural period of the supported pipe is close to the fundamental period
of the pier structure. Flexible connections/sections should be used to bridge across
expansion joints or other locations where needed.
Cathodic Protection Systems (CPS). Provide special and detailed
considerations for cathodic protection systems (CPS). This applies to pierside utility
systems and the associated landside utility systems. Specific details are required for
storage structures and the interface transition between the landside systems and the
pierside systems. The services of a qualified corrosion engineer must be provided
unless defined otherwise by the cognizant NAVFAC EFD/EFA OR USACE DISTRICT.
For additional information and requirements see MIL-HDBK-1004/10, Electrical