Quality assurance methods demonstrated with the calculation of sound propagation with ISO 9613-2 and with CNOSSOS-EU

摘要

Many methods have been developed and where even implemented in legally binding rules how sound propagation shall be calculated to support the minimization of environmental noise. Especially in the case of such legal requirements it is necessary to ensure that the agreed algorithms are applied in the same way by all experts independent from the software tool they use. With the series of the International Standard ISO 17534 we created a framework to ensure this necessary precision. One of the main pillar of the strategy is to clarify all ambiguous definitions and to close the gaps that will cause different results if programmed by different software developers. With standard ISO 9613-2 examples are shown where even existing definitions had to be modified. It can be stated that all calculation methods have their shortcomings that can only be detected if the method is realized in software and then practically applied. The same is true with the harmonized European calculation method -- here abbreviated as "CNOSSOS-EU". Examples are shown where it was necessary to modify and clarify some definitions before it was possible to create test cases to check the correct implementation of the method. With this work on about 30 Test Cases for ISO 9613-2 and for CNOSSOS-EU we learned a lot about the optimal strategy if a new method shall be implemented or an existing method shall be improved. Some recommendations for future projects of that type will be given.