Practical Process Engineering

Some comments on #Pipe_Schedule👇🏼👇🏼👇🏼👇🏼 Pipe Schedule or Schedule number is a dimensionless number. Schedule Numbers for pipe size/wall thickness combinations are approximated to get a uniform relationship equal to 1000 times the P/S (P=Design Pressure and S=Allowable Stress) expression contained in the modified Barlow formula for pipe wall thickness. The pipe schedule is abbreviated as SCH. For a given size and schedule the thickness of the pipe is fixed and defined in the applicable ASME standard (B 36.10/B 36.19). Even though Pipe thickness can also be specified in mm or inches to the value corresponding to that specified in the ASME standard, The Schedule Numbers are strictly used as a convenient designation system while ordering piping item. For any given pipe size and varying schedule numbers or thicknesses its Outside Diameter (OD) remains constant and Internal Diameter (ID) varies. With increase in thickness the strength increases but its ID decreases. OD is kept constant to help the support hardware design so that the same support hardware can be used for same pipe size (varying thicknesses). In the oil and gas and related downstream industries the most common standards are ASME B 36.10 Welded and Seamless Wrought Steel Pipe, and ASME B36.19 Stainless Steel Pipe #Nominal_Pipe_Size: The size of all pipe is identified by the nominal pipe size. The manufacture of pipe NPS 1⁄8 (DN 6) to NPS 12 (DN 300), inclusive, is based on a standardized outside diameter (OD). This OD was originally selected so that pipe with a standard OD and having a wall thickness that was typical of the period would have an inside diameter (ID) approximately equal to the nominal size. Although there is no such relation between the existing standard thickness — OD and nominal size — these nominal sizes and standard ODs continue in use as ‘‘standard.’’ As For all pipe sizes the outside diameter remains constant. Therefore any variation in schedule i.e. wall thickness, affects only the inside diameter. As the schedule number increases, the wall thickness increases, and the actual bore is reduced. **** Standard (STD) is identical to SCH 40 up to NPS 10. All larger sizes of Standard have 9.53 mm wall thicknesses. ****Extra-Strong (XS) is identical to SCH 80 up to NPS 8. All larger sizes of Extra-Strong have 12.70 mm wall thicknesses. ****Double Extra Strong (XXS) wall is thicker than SCH 160 from NPS 1/8 to NPS 6, and SCH 160 is thicker than XXS wall for NPS 8 and larger. Pipe of sizes and wall thicknesses other than those of Standard, Extra-Strong, and Double Extra-Strong, and Schedule Number were adopted from API Specification 5L.

Above posts are an introduction to ASME B31 and its divisions and extracted from below website. For more information about this invaluable standard, please take a look at below address: https://www.controleng.com/single-article/navigating-asme-b31/69b74b11b99fa1194fca0890f4bf2b1a.html

There are two more files relating to ASME B31.👇🏼👇🏼👇🏼

#ASME_B31_12_Hydrogen_Piping_and_Pipelines: This section covers piping in gaseous and liquid hydrogen service, and pipelines in gaseous hydrogen service. This section was first published in 2008.

#ASME_B31_9_Building_Services_Piping: This section covers piping typically found in industrial, institutional, commercial, and public buildings; and multi-unit residences, which does not require the range of sizes, pressures, and temperatures covered in ASME B31.1. This section is similar to ASME B31.1 and B31.3, but is less conservative (specifically when calculating minimum wall thickness) and contains less detail. It is limited to low pressure, low temperature applications indicated in Paragraph 900.1.2 of ASME B31.9. This was first published in 1982.

#ASME_B31_8_Gas_Transmission_and_Distribution_Piping_Systems: This covers piping transporting products that are predominantly gas between sources and terminals, including compressor, regulating, and metering stations; and gas gathering pipelines.

#ASME_B31_5_Refrigeration_Piping_and_Heat_Transfer_Components: This section covers piping for refrigerants and secondary coolants.

#ASME_B31_4_Pipeline_Transportation_Systems_for_Liquids_and_Slurries: This section covers piping transporting products that are predominantly liquid between plants and terminals and within terminals, pumping, regulating, and metering stations.

#ASME_B31_3_Process_Piping This section covers piping found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. This section is very similar to ASME B31.1, especially when calculating minimum wall thickness in straight pipe.