Proposal for an improved approach for the simplified force calculation procedure after rapid valve closure in the European standard EN 13480-3

摘要

The European standard EN 13480-3 addresses the design and calculation of metallic industrial piping. In annex A of this standard simplified calculation procedures for dynamic loadings are given, among others for the event "rapid valve closure". Because a definition of the so-called effective valve closure time that is used in the equations of the standard is missing, in praxis often the total closure time is applied that is the parameter, which is known by the user of the standard. By means of a test case and comparative dynamic pressure surge analyses it is shown that in this case the forces are evaluated much too low especially for short pipe segments. Furthermore, it is criticized that application limits, e.g. for gas flow or in case of column separation and rejoining, are not clearly specified. A new approach for a simplified force calculation for one-phase liquid flow is proposed, in that the total valve closure time can be applied.