Load pipe externally

Pipe-Wall Thickness. Once the design pressure and temperature have been established and the pipe material and size selected, the wall thickness is calculated using the appropriate section of the code. In rare cases, a thin pipe must be made thicker to withstand handling. Occasionally the thickness is affected by external loads or vibrations. All codes prescribe essentially the same design formula for metallic hoUow circular cylinders under internal pressure ... 

Another loading condition in underwater applications is the application of external hydrostatic stress to plastic structures (also steel, etc.). Internal pressure applications such as those encountered in pipe and... 

This value is the basic standard that AWWA M-II specifies for steel conduit and pipe, as do the ASTM and ASME. As is obvious, there are a number of factors that contribute to pipe deflection. These are the external loads that will be imposed on the pipe, both the dead load of the overburden as well as the live loads of such things as wheel and rail traffic. The factors affecting RTR pipe deflection can be summarized as follows ... 

External loads imposed by piping and attached equipment. 

There will be no significant loading from piping and external equipment. Earthquake loading need not be considered. 

ASTM, Standard Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel-Plate Loading, ASTM D2412-02, American Society for Testing and Materials, West Conshohocken, PA, 2002. 

Except for piping with a nominal wall thickness of 13 mm (V2 in.) or less, the piping system shall be safeguarded (see Mandatory Appendix III) from external loads, such as maintenance loads, impact loads, and thermal shock. 

Piping joints shall be selected to suit the piping material, with consideration of joint tightness and mechanical strength under expected service and test conditions of pressure, temperature, and external loading. Layout of piping should, insofar as possible, minimize stress on joints, giving special consideration to stresses due to thermal expansion and operation of valves (particularly a valve at a free end). 

An expansion joint that depends on external main anchors to restrain pressure end load shall be tested in place in the piping system. 

Steel pipe used for service lines shall be installed in such a manner that the piping strain or external loading shall not be excessive. 

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