Ehdotuksen tiedot

In general terms, Miner’s rule is a common approach to calculate how the accumulation of a specific load that varies over time effects the time until failure. This international standard specifies the application of Miner’s rule for calculating the design time until failure of plastics pipes and piping systems of plastics materials under varying, but known, load conditions. Miner’s rule can also be applied reciprocally to calculate the tolerable load levels along a desired design time. This international standard specifies particularly the application of Miner’s rule to calculate stress or pressure regimes, respectively, that are tolerable during a targeted design time for plastics or composite pipes. Further, the application of Miner’s rule on the effect of accumulated damage on polyolefins caused by oxidative attack under varying temperatures and times on the design life is specified. It is necessary to apply Miner's rule to each failure mechanism separately. Thus, for mechanical failure due to internal pressure, other failure mechanisms, such as oxidative or dehydrochlorinative degradative failure mechanisms, are to be neglected (assuming, of course, no interaction). A material may be used only when it is proven to conform to all failure mechanism criteria. NOTE Miner's rule is an empirically based procedure and is only a first approximation to reality.