ISO 13760 pdf download

ISO 13760 pdf download.Plastics pipes for the conveyance of fluids under pressure – Miner’s rule一Calculation method for cumulative damage 1 Scope This International Standard specifies a method for calculating the maximum allowable hoop stress applicable to pipes exposed to varying internal pressures and/or temperatures during their expected lifetime. This method is generally known as Miner’s rule. 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. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of the publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 1 0508:1 995, Thermoplastics pipes and fittings for hot and cold water systems. An illustrative example is provided by the calculation of the expected service life of hot-water pipes, viz: class 2 as defined in ISO 1 0508. This International Standard specifies, during a 50-year service life, a temperature profile consisting of 49 years at the standard operating temperature T o of 70 °C, 1 year at the maximum operating temperature T max of 80 °C and 1 00 h at the malfunction temperature T m of 95 °C to allow for heater control faults. To derive the proper wall thickness (or rather the ratio SDR, i.e. the diameter/wall thickness ratio), it is necessary to know the maximum permissible hoop stress in the pipe wall that will withstand the given conditions. However, the proposed class specifications state that, in the case of polybutylene for instance, a safety factor of 1 ,5 is to be applied to the stress at T o , a safety factor of 1 ,3 to the stress at T max and a safety factor of 1 ,0 to the stress at T m (this already being a safety factor in...