scope:

Content and Coverage

(a) This Code prescribes requirements for the materials, design, fabrication, assembly, erection, examination, inspection, and testing of piping. 

(b) This Code applies to piping for all fluids, including:

   (1) raw, intermediate, and finished chemicals;

   (2) petroleum products;

   (3) gas, steam, air, and water;

   (4) fluidized solids; and

   (5) refrigerants;

except as provided in para. 300.1.2 or 300.1.3.

(c) Except as excluded in para. 300.1.3, this Code covers all piping within the property limits of facilities engaged in the processing or handling of chemical, petroleum, or related products. Examples are a chemical plant (including nonradioactive fluids in a nuclear fuel reprocessing plant), petroleum refinery, loading terminal, natural gas processing plant (including liquefied natural gas facilities), bulk plant, compounding plant, and tank farm. See Fig. 300.1.1 for a diagram illustrating the scope of B31.3¹ piping.

Packaged Equipment Piping

Piping which interconnects individual pieces or stages of equipment within a packaged equipment assembly shall be in accordance with B31.3, except that packaged refrigeration piping may conform to either B31.3 or B31.5.

Exclusions

This code excludes the following:

(a) piping systems designed for internal gage pressures at or above zero but less than 105 kPa (15 psi), provided the fluid handled is nonflammable, nontoxic, and not damaging to human tissue as defined in 300.2, and its design temperature is from -29°C (-20°F) through 186°C (366°F);

(b) power boilers in accordance with BPV Code2 Section I and boiler external piping which is required to conform to B31.1;

(c) tubes, tube headers, crossovers, and manifolds of fired heaters, which are internal to the heater enclosure;

(d) pressure vessels, heat exchangers, pumps, compressors, and other fluid handling or processing equipment, including internal piping and connections for external piping;

(e) piping located on company property which has been set aside for pipelines conforming to B3 1.4, B3 1.8, or B31.11, or applicable governmental regulations;

(f) plumbing, sanitary sewers, and storm sewers; and

(g) fire protection systems constructed in compliance with insurance underwriters' or other recognized fire protection engineering standards.

¹B31 references here and elsewhere in this Code are to ASME B31 Code for Pressure Piping and its various Sections as follows:

   B31.1, Power Piping

   B31.3, Chemical Plant and Petroleum Refinery Piping

   B31.4, Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohols

   B31.5, Refrigeration Piping

   B31.8, Gas Transmission and Distribution Piping Systems

   B31.11, Slurry Transportation Piping Systems