Questions & Answers
In my old Excel files different test pressure (Pf) values are generated for the multilayer piping systems test according ISO 21003-5. I get one set of values from the ISO 9080 prediction table and a slightly different value, when I use the linearized LPL equation according to ISO 21003-2, which values should I use?
In the ISO 21003-5, fitness for purpose of the piping system pressure, calculations have to be made on the construction for hydrostatic pressure testing and the bending test. For the given formula in the standard, the actual calculated LPL values (from ISO 9080 prediction table) shall be taken and not the derived LPL values from the linearized LPL line. Small differences might occur as the real LPL line is not a perfect linear line. Do not take the 95% values of these LPL values as they are only used for the “control points” testing.
Marco Mekes