Hello ncamilli,
The ASME B31 Code for Pressure Piping:
The original ASME B31 Code for Pressure Piping was tentatively introduced in 1935 as a single all inclusive document for piping design. Beginning in 1955, various sections were "split-off" to address the designs of specific piping systems. The group that is now ANSI has in the past been know as ASA and USASI. For a number of years the terminology was ASA/ASME B31 and ANSI/ASME B31 and now just ASME/B31.
B31.1 Power Piping is intended for piping associated with power plants and district heating systems. It also covers geothermal heating systems. Generally it addresses the steam-water loop in the generation application.
B31.2 was the Fuel Gas Piping Code until it was withdrawn in 1988 and responsibility for that piping was assumed by ANSI Z223.1. It was a good design document and although it has been withdrawn ASME makes it available as a reference.
B31.3 Process Piping (once was called the Chemical Plant and Petroleum Refinery Piping Code) is perhaps the Code with the broadest coverage. Because the B31.3 coverage is so broad it has several "fluid categories" to assure the proper degree of rigor is assigned to various types of piping.
B31.4 Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia and Alcohols holds the record for the B31 Code with the longest title. Basically it is a buried pipeline transportation Code for liquid products.
B31.5 Refrigeration Piping is rather self explanatory.
B31.6 was at one time going to be the Chemical Plant Piping Code but the 1974 draft document was so parallel to the existing B31.3 that the decision was taken by B31 Main Committee to fold it into B31.3 before it was published.
B31.7 Nuclear piping was withdrawn after two editions and responsibility was assumed by ASNR B&PV Code, Section III, Subsections NA, NB, NC and ND.
B31.8 Gas Transmission and Distribution Piping Systems addresses the transportation of gasses and it too is largely a buried piping Code. The Code of Federal Regulations (49CFR) has assumed the force of law for these types of piping systems.
B31.9 Building Services Piping addressed typical pressure piping systems that are designed to serve commercial and institutional buildings. Basically it addresses systems that require less design and fabrication rigor than does, for example, B31.1. There are various limits on the design parameters (e.g. temperature, pressure, pipe size, etc.) that this Code includes in its scope.
B31.10 Cryogenic Piping Systems was also (like B31.6) in the process of development when the Committee recognized that the 1981 draft was very parallel to B31.3 and the decision was taken to also "fold it into" the B31.3 Code. You can see haw the B31.3 Code grew to have such broad coverage.
B31.11 Slurry Piping Systems is another transportation pipeline Code that applies for the most part to buried piping systems that transport slurries.
B31.12 will be the new Hydrogen Piping System Code when it is released by ASME.
Each of the surviving B31 Pressure Piping Codes includes a scope of what is included and what is explicitly excluded (e.g., B31.1 excludes pulverized coal fuel piping)
I hope this helps.
Regards, John.
