ISO/TS 10986:2021 pdf download – Plastics piping systems — Glass-reinforced thermosetting plastics (GRP) pipes — System design of above ground pipe and joint installations without end thrust.
5.2 Supporting of pipes 5.2.1 General A range of joint designs are manufactured for which a variety of support configurations are recommended. Generally, pipes are supported on either side of the joint, but some systems allow direct support under the joint. To minimize the loads induced in pipes and supports, the supports should not restrain longitudinal expansion of the pipes. However, it is essential that the pipe movements be guided and controlled in such a way that all pipe sections are stable and that acceptable longitudinal movement of the pipe in the couplings is not exceeded. As non-restrained couplings are flexible, it is very important for the stability of every pipe component to be ensured by the supports. Each pipe should therefore be supported by at least two cradles and anchored by a pipe anchor at one of these cradles, while the remaining cradles should be designed as guides, allowing longitudinal expansion of the pipe but restraining lateral movements. With direct support under the joints, the coupling clamp can act as anchor, see Figure 6 (1) and Figure 8. For pipes supported in more than two cradles, the cradle closest to the middle of the pipe should be used as an anchor. The anchors should be located with regular spacing to ensure even distribution of longitudinal pipe expansion on the joints. However, the maximum distance between two anchors shall not result in exceeding the draw limits specified for the joint given in ISO 23856. Figure 6 shows typical support arrangements for pipes.
5.2.3 Loads on supports The supports should be rigid and designed to withstand the loads caused by: — external and environmental loads, — weight of pipe and fluid, — reaction forces caused by internal pressure, — friction induced in couplings and against guides in case of temperature and/or pressure variations. — head loss in pipe. It is the responsibility of the owner’s engineer to determine the actual design loads for the supports. NOTE The reaction forces, caused by the weight of water, act perpendicular to the pipe. For pipe installations on steep slopes this results in a significant horizontal load component acting on the pipe foundations. A common error is to regard the reaction from water as vertical since it is a gravitational force. Table 3 provides approximate axial forces that should be considered in the design of support cradles. These loads result from contraction and elongation of pipes during operation and frictional resistance in the gasketed joint. Table 3 assumes simultaneous expansions and contractions of the neighbouring pipes. If non- simultaneous expansions and contractions can be expected, contact the pipe supplier for adequate axial forces.