ASME B31.4-2019 pdf download
ASME B31.4-2019 pdf download.Pipeline Transportation Systems for Liquids and Slurries.
Ice Loads. The following effects shall be considered when designing for ice loads: (a) ice frozen on pipelines and supporting structures (b) drifting ice (river ice breakup or in inshore waters) (c) impact forces due to thaw of the ice (d) forces due to expansion of the ice 401.2.3.4 Road and RailTraffic. Earthloadandcyclic rail and truck loads shall be considered. Maximum traffic axle loads shall be established in consultation with the appropriate traffic authorities and others operating in the vicinity of the pipeline. 401.2.3.5 Vibration. Loads resulting from vibration (including Karmon vortex effect) and resonance shall be considered. 401.2.3.6 Waves and Currents. Loads resulting from waves and currents shall be considered in the design of pipelines across waterways. 401.2.3.7 Temperature Effects. The design tempera- ture is the metal temperature expected in normal opera- tion. Itis not necessary to vary the design stress for metal temperatures between −20°F (−30°C) and 250°F (120°C). However, some of the materials conforming to specifica- tionsapprovedforuseunderthisCodemaynothaveprop- erties suitable for the lower portion of the temperature band covered by this Code. Attention shall be given to the low-temperaturepropertiesofthematerialsusedforfacil- ities to be exposed to unusuallylowground temperatures, low atmospheric temperatures, or transient operating conditions. The design temperature should be established consid- ering temperature variations resulting from pressure changes and extreme ambient temperatures. Consideration should be given to possible conditions that may cause low temperatures on pipelines trans- porting liquids that become gases at or near atmospheric conditions. See ASME B31T for more information about evaluating the suitability ofpiping materials that may be subject to brittle failure due to low-temperature service conditions.
When calculating equivalent stresses or strains, the most critical combination of sustained, occasional, construction, and transient loads that can be expected to occur shall be considered. Ifthe operatingphilosophyis to maintain full operation during extreme environmental conditions, the system shall be designed for concurrent action of the expected sustained and occasional loads. Ifthe operating philosophy is such that operations will bereducedordiscontinuedunderextremeenvironmental conditions, the following load combinations shall be considered: (a) the design operating loads plus the environmental loads at the permissible level (b) the reduced operating loads plus the maximum en- vironmental loads Unless they can be reasonably expected to occur together, it is not necessary to consider a combination of transient loads in combination with occasional loads.
Effects ofsustained loads caused by deformations shall betakenintoaccountonlytotheextentthatthecapacityto withstand other loads is affected. When combining environmental loads with construc- tion loads, the environmental loading should be selected to reflectthe mostsevere loadinglikelyto be encountered during the construction phase. When consideringloads duringtests, itis notnecessary to consider occasional or transient loads as occurring concurrently with the sustained and construction loads existing at the time of the test.In no case where the Code refers to the specified minimum value of a physical property shall a higher value ofthe propertybe used in establishingthe allowable stress value. PipelineswithinthescopeofthisCodemaybesubjectto conditions during construction and operation where the external pressure exceeds the internal pressure. The pipe wall selected shall provide adequate strength to prevent collapse, takinginto consideration mechanical properties, variations in wall thickness permitted by material speci- fications, out-of-roundness, bending stresses, and external loads. The forces and moments transmitted to connected equipment, such as valves, strainers, tanks, pressure vessels, and pumps, shall be kept within stress limits specified herein and in other applicable codes. External or internal coatings or linings ofcement, plas- tics, or other materials may be used on steel pipe conforming to the requirements ofthis Code. These coat- ings or linings shall not be considered to add strength unless it can be demonstrated that they do so. All in-line pipe and pipeline components shall be designed to allow passage of instrumented internal inspection devices.
