How can be dealt with stresses due to internal and external overpressure?
An overload of a pressure pipe system due to internal overpressure results, especially in association with additional heat effects, to a continuous expansion of the pipe until it breaks. The danger of an expansion arises as a result of a too small wall thickness, in which an indiscriminate wall thickness increase is not justifiable. In the presence of heat expansion, a wall thickness enlargement also increases the reactive forces on the pipe fixed points. The engineer must ensure that the wall thickness is designed to meet requirements while the pipe remains elastic in response to any length changes that might arise. A sudden change in structural operating conditions due to internal pressure leads to pressure surges. The distinctive elasticity of the plastic pipe has the advantage that the extreme values of pressure waves are significantly lower than in steel pipes. Despite this fact, pipe systems operated by pumps or containing rapidly closing shut-off valves must be tested for any fo
