UNE 53331:2020

The purpose of this standard is to establish the criteria for testing of PVC-U, PVC-O, PE and PP tubes, compact and of uniform density, in the section of the tube, to be used in buried pipes, with or without pressure, subjected to external loads.



This standard covers the field of application of buried facilities, including the different types of ditch, pipe arrangement and supports most commonly used for plastic materials. When the pipe is installed on discontinuous supports, hung or in other special conditions, appropriate calculation methods shall be used, depending on the expected efforts.



When applying this standard, a series of parameters and values that have been empirically established shall be selected, so that the results obtained by calculation coincide substantially with those obtained in the tests carried out, with the designer choosing the appropriate ones.



The structure of the standard is as follows:



Once the appropriate pipe for the considered conduit has been selected, as well as the type and support of the trench, the factors acting on the pipe are determined, due to external and internal loads, analyzing whether the deformation of the pipe is admissible according to the established limit of 5%. In positive case, the calculation of the solicitations to which the conduction is subjected is continued, determining the maximum tangential stresses of the material, which shall exceed the established safety criteria, as well as those related to the critical collapse pressure, the pressure water outside and the simultaneous action of both. If the deformation exceeds 5%, another assumption should be considered, modifying the characteristics of the installation or the type of tube.



Annex K gives a list, not exhaustive, of the documents describing the pipes to which this standard applies.