1 March 1997
8-1. PIPE MATERIALS, FITTINGS, AND JOINTS.
(1) Factors to be considered in the selection of pipe materials and piping systems for
sewers or force mains are:
-Flow characteristics or friction coefficient.
-Life expectancy and history of use.
-Resistance to acids, alkalis, high temperature, or corrosive wastes, and corrosive soils.
-Ease of handling and installation.
-Physical strength and pressure ratings.
-Joint water tightness and ease of installation.
-Availability of pipe in required sizes, strengths. etc.
-Availability of fittings, connections, and adapters.
Pump suction and discharge piping inside the station will normally be ductile iron or steel.
However, other pipe materials covered in this paragraph are not precluded from use. Pipe,
fittings, and joints serving as force mains will be selected to withstand the maximum internal
operating pressures, including transient surges. The project specifications will indicate the
appropriate pressure class and rating for each pipe application. No pipe manufactured is suitable
for all installation requirements and conditions. The pipe materials covered in this paragraph are
the ones most often used for sewers and force mains carrying sanitary and industrial wastes.
Each type of pipe will be evaluated to determine its suitability for the particular design. Pipe
materials found inappropriate for use will be deleted from the project specifications. Asbestos-
cement pipe shall not be installed.
(2) Where iron or concrete pipe are to be considered, special attention will be paid to
subsurface and soil conditions. The characteristics of the soil in which a pipe is placed affect the
rates of corrosion, with the most corrosive soils being those having poor aeration and high values
of acidity, electrical conductivity, dissolved salts, and moisture content. The relative potential for
corrosion is best estimated by evaluating the degree of corrosion of existing metallic or concrete
pipelines previously buried in the soil. Facility engineer personnel will normally have knowledge
of these matters. When this information is not available, or is nonconclusive, resistivity tests of
the soil will be conducted at several locations within the system and compared to data from pipe
manufacturers. Typically soil with a resistivity above 30,000 ohm-cm is not likely to cause
corrosion in steel pipe. More information on controlling corrosion can be found in TM 5-811-7
and the National Association of Corrosion Engineers Standard PR0169, Control of External
Corrosion on Underground or Submerged Metallic Piping Systems.