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What is the difference between pipe schedule and class?

Jeffrey Rodriguez

in Homework Help

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Tara Andrews on July 8, 2019

There are a number of misunderstandings and misconceptions regarding the classification of the pipe – and most of these originate primarily because some engineers simply do not use common sense. Some would like to think that there is an almighty, all-powerful body at some place that dictates what a pipe is, will be, and will be established and fulfill "the law," codes, or "rules". There is No animal that exists.\n. \nif it is not said that the wrong information if you are told "pipe class refers to the maximum internal pressure a pipe can safely sustain". The important point to note here is that the pipe itself may not (and in most cases, not) to set the maximum safe allowable pressure in the ENTIRE piping system involved. In most cases, the flanges are the weakest point, and this should be the guide factor of design with respect to the allowable pressure in the piping class(ification).\n. \nA pipe class is a document (normally prepared by an operating or engineering company) for use within their boundaries, and that contains the definition of pipe and all related components that are used in a specific pressure, temperature condition – including sometimes the service they are in. A typical definition contains the material specification, type, rating and dimensions of the data. Serves as a CLASSIFICATION of piping systems and their application in the design process in the hand. A certain pipe of programming is often established for certain services. This is determined by the classification, based on the need and application.\n. \nA tube programming and serves as the basis of the specification for the pipe thickness and dimensions. You should know that the hoop stress equation is what determines the thickness of the pipe, so that you will not be wondering if the thickness of the pipe determines the pressure range of work. You SHOULD KNOW that not – and under what conditions.\n. \nIndustrial pipe thicknesses follow a formula, expressed as the "schedule number" as established by the American Standards Association (ASA) now re-organized as ANSI - American National Standards Institute). Eleven schedule numbers are available for your use: 5, 10, 20, 30, 40, 60, 80, 100, 120, 140, & 160. The more popular the programming, for the moment, is 40. Schedules 5, 60, 100, 120, & 140 rarely, if ever, has been employed by me in more than 48 years as a practicing engineer. The schedule number is defined as the approximate value of the expression:\n. \nSchedule Number = (1,000)(P/S)Where,\nP = the internal working pressure, psig\nS = is the allowable stress (psi) for the material of construction in the conditions of use.\n. \nfor example, the schedule number of ordinary steel pipe having an allowable stress of 10,000 psi for use at a working pressure of 350 psig would be:\n. \n. \n. \nSchedule Number = (1,000)(350/10,000) = 35 (approx. 40)\n. \nI can understand your confusion and ignorance from a student's point of view. The students are not exposed to this methodology and are initiated into when they go into the real world on your first job(s).

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