21 JANUARY 2003
18.104.22.168. API 570 Inspections. Besides routine pipeline inspections, periodic inspections by an
expert certified to the standards of API 570 will provide documentation of remaining pipeline life
and any need for replacement. This may be funded by DESC.
2.5. General Pipeline System Components.
2.5.1. Expansion Joints. Pipelines are arranged to allow for expansion and contraction caused by
changes in ambient temperature. Where possible, accommodate expansion and contraction by
changes the direction of piping runs, offsets, loops, or bends. When this is not practicable, use
flexible ball joint offsets. Do not use expansion devices that use packings, slip joints, friction fits, or
other non-fire-resistant arrangements. Ball-type offset joints are used to accommodate possible
settling of heavy structures such as storage tanks if piping design cannot provide enough flexibility.
Expansion bends, loops, and offsets are designed within stress limitations of American Society of
Mechanical Engineers (ASME) B31.3, Process Piping, and ASME B31.4, Liquid Transportation
Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohols.
2.5.2. Manual Valves. Manual valves are used on pipelines to control flow and to permit isolating
equipment for maintenance or repair.
22.214.171.124. Full port valves are installed on pipelines to allow pigging.
126.96.36.199. Do not use gate valves in aircraft fueling systems, except where the pipeline is
pigable and absolute shut-off is not required.
188.8.131.52. For specific valve types and locations, see MIL-HDBK-1022A.
2.5.3. Surge Suppressors. If the flow of liquid in a pipeline is suddenly stopped, an excessively high
pressure is instantly created because the kinetic energy of flow is converted to pressure energy. The
resulting shock often causes leaks and damage to connected equipment. A common device designed
to decrease shock in pipelines is a surge suppressor of the diaphragm or bladder type. It is equipped
with a top-mounted liquid-filled pressure gauge, isolation valve, limited bleed-back check valve, and
drains. The surge suppressor will be as close as possible to the point of shutoff that is expected to
cause the shock. Surge suppressors can reduce shock pressure but will not end it entirely.
2.5.4. Miscellaneous. Miscellaneous equipment found in pumping stations include control panels,
gauges, fire-fighting equipment, water detectors, sump pumps, compressed air systems, and
electronic measuring devices. These components vary with the type of system and are considered
accessory equipment for the major components of the system.
2.6. General Pipeline System Repairs.
2.6.1. General Pipeline Leaks. Most pipeline leaks are caused by interior or exterior corrosion. Less
frequent causes of leaks include cracked welds, split seams and joints, separation at collars, buried
flanges, and threaded pipe. Initial repairs can be made by placing clamps over the damaged area and
using sealing epoxy components or gaskets to seal the leak. These repairs are usually temporary and
modern practice is to weld all leaks (API RP 1107). The LFM should make sure that schematics are
annotated to show where major breaks and leaks have occurred in the pipeline.
2.6.2. Pits and Small Leaks. Pits on the exterior of a pipeline are caused by corrosion. If discovered
before a leak develops, repair them by arc welding. Welding a circular patch over the hole may repair