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4.2.5.3 Exceptional operating conditionsExceptional operating conditions shall be rarely occurring events.For the calculation under exceptional operating conditions, in addition to normal loadings given in4.2.5.1, each of the following conditions shall be examined: possible exceptional climatic effects, e.g. exceptional snow and wind corresponding to the localconditions; seismic conditions (Safe Shut‐down Earthquake).4.2.5.4 Test conditionsFor the calculation under test conditions, all static, dynamic and kinematic boundary conditions shall betaken into account.Each of the following conditions shall be examined: internal pressure (test gauge pressure and static head); dead weight of piping, including internal structures and attached equipment; weight of insulation (partially or completely applied); weight of test fluid;
A.1 GeneralIn addition to the static conditions and cyclic pressure and temperature loadings covered by 4.2, pipingmay be subjected to a variety of dynamic loadings. Dynamic events should be considered in the designof the piping. However, unless otherwise specified, such consideration may not require detailedanalysis. The effects of significant dynamic loads should be added to the sustained stresses in the designof the piping. Continuous dynamic loads should be considered in a fatigue analysis.Where the dynamic event produces reverse forces, it may be acceptable to derive maximum loadings bycombining those forces whose direction makes them additive to the static loads. However, care shouldbe taken regarding the displacements as both plus and minus movements may be needed for layout andsupporting detail design.There are a number of methods for the calculation of the effect of dynamic events, such as:a) simplified static equivalent;b) quasi‐static equivalent;c) shock response spectra modal analysis;d) force time history.
Experience has shown that for properly supported piping, the use of simplified methods generally leadsto acceptable engineering solutions for the prevention of damage during dynamic events. Wherecomplex analysis is to be undertaken, care should be exercised in the selection of suitable programmesand consistent data for the derivation of forces and allowable loads.Piping and piping components may also be analysed by subjecting full or part scale models to avibratory regime comparable to the expected dynamic loading.
