ASME B31 Code Outlines
The ASME B31 Code for Pressure Piping is a set of standards developed by the American Society of Mechanical Engineers (ASME) that provides guidelines and requirements for the design, materials, construction, assembly, inspection, and testing of piping systems. The code is divided into several sections, each addressing different types of piping systems.
ASME Code B31.1 Power Piping
Includes:
1. Power and auxiliary service piping systems for electric generating plants.
2. Industrial and institutional plants (also see ANSI Code B31.9).
3. Central and district heating plants (also see ANSI Code B31.9).
4. All piping and parts within or part of plants as previously specified, unless specifically excluded.
5. Boiler external piping, covered under the ASME Code, Section I, stamping requirements.
6. Geothermal steam and hot water piping.
7. Oil or gas piping downstream of the meter within the plant identified in 1, 2, or 3 above.
8. Air and hydraulic distribution system.
Excludes:
1. Piping covered explicitly by other ANSI/ASME sections.
2. Components covered by ASME B and PV Code.
3. Fuel gas in industrial and institutional plants.
4. Building heating and distribution steam piping for 15 psi (100 kPa) gauge or less or hot water systems for 30 psi (200 kPa) gauge or less.
5. Roof drains, floor drains, plumbing, sewer or fire protection systems.
6. Piping for hydraulic or pneumatic tools.
7. Piping for nuclear power plants.
ASME Code B31.2: Fuel Gas Piping
Includes
1. Natural gas.
2. Manufactured gas.
3. LPG - air mixtures above the combustible limit.
4. LPG - in the gaseous state.
Excludes:
1. Fuel gas piping where the metal temperature is above 450°F (232°C) or below -20°F (29°C).
2. Fuel gas piping covered by the ASME Codes B31.1, B31.3, 831.8, 221.30, or Z106.1
3. Pressure vessels covered by the ASME B and PV Code.
4. Gas gathering, transmission, and distribution systems covered by ANSI Code 831.8.
5. LPG in the liquid state.
6. Fuel gas-air mixtures in the combustible or flammable range.
ANSI Code B31.3: Chemical Plant and Petroleum Refinery Piping
Includes
All piping within the property limits of facilities engaged in the processing or handling of chemical, petroleum, or related products.
Excludes
1. Nonhazardous fluid piping with pressure between 0 and 15 psi ( 100 kPa) and temperatures ranging from -20°F (-29°C) to 366° F (186°C).
2. Piping covered by the ASME B and PV Code, Section I. or ASME Code B31.1, which requires Section I, Inspection and Stamping (B.E.P. Piping).
3. Pressure vessels, heat exchangers, pumps, etc., including internal piping and connections for external piping.
4. Piping within the property limits designated for design according to the ASME Code 831.4 or B31.8 or to government regulation (pipeline rights-of-way).
5. Plumbing or sewers.
6. Piping for fire protection systems (covered by insurance underwriter's requirements).
ANSI Code 831.4: Liquid Petroleum Transportation Piping Systems
Includes
1. Piping transporting liquid petroleum and petroleum products between the producer's facilities arid delivery and receiving points.
Excludes
1. Water, air, steam, lube oil, gas, and fuel piping.
2. Pressure vessels, heat, exchangers, pumps, meters, etc., including internal piping and connections to external piping.
3. Piping systems designed for internal pressure less than 15 psi (100 kPa).
4. Piping systems designed for internal pressures greater than 15 psi (100 kPa) where the design temperature is below -20°F (-29°C) or above 250°F (120°C).
5. Casing, tubing, or pipe used in oil wells, wellhead assemblies, and piping connecting those assemblies.
6. Piping covered by the ASME Code 831.3 or B31.8.
7. Ammonia refrigeration piping systems.
ASME Code B31.5: Refrigeration Piping
Includes
1. Refrigeration and brine piping systems down to -350°F (-196°C) either erected on the premises or factory assembled unless specifically excluded.
Excludes
1. Self-contained refrigeration systems covered by requirements of Underwriter's Laboratories or other nationally recognized testing laboratories.
2. Water piping systems.
3. Piping systems with internal or external pressure of 15 psi (100 kPa) or less.
ASME Code B3'1.8: Gas Transmission and Distribution Piping
Includes
1. Gas transmission pipelines.
2. Gas compressor stations.
3. Gas metering and regulation stations.
4. Gas mains.
5. Service lines to the outlet of customer's meter set.
6. Gas storage lines and storage equipment of the closed-pipe type.
Excludes:
1. Pressure vessels and piping covered by the ASME B and PV Code.
2. Piping systems with metal temperatures above 450°F (232°C) or below - 20°F (-29°C)
3. Piping in a chemical plant or refinery property limits, natural gasoline extraction plants, etc., covered by ASME Code B31.3.
4. Atmospheric vent piping for waste gases.
5. Low-pressure gas, which is covered by ASME Code 831.4.
6. Wellhead assemblies.
7. Proprietary items of equipment.
ASME Code B31.9: Building Services Piping
Includes:
1. Piping systems for building services for industrial, commercial public, institutional, and multi-unit residential buildings.
Examples:
A. Dual temperature water for heating and cooling.
B. Chilled water.
C. Condensing water.
D. Hot water.
E. Steam and condensate return.
F. Compressed air and other nonflammable gases.
G. Fuel gas over 60 psi (415 kPa) (fuel gas under 60 psi is covered by the new ANSI Code Z223. 1)
Excludes:
1. Pressure limit exclusions:
A. Steam: 125 psi (860 kPa) Gauge
B. Nonfuel gas: 125 (860 kPa) Gauge
C. Liquids: (300 (2,070 kPa) Gauge
D. Full vacuum for all fluids
2. Other exclusions:
A. Piping system covered by ASME Code B31.1
B. Sanitary, potable water, and storm drain piping
C. Fire protection systems
D. Acetylene, hydrogen, oxygen, and medical gas piping
E. Fuel oil piping
ASME Code B31.10: Cryogenic Piping
Includes:
1. Liquid-solid mixtures (or slush), operating at temperatures ranging from
-244 °F (-153°C) to -459°F (-273°C), either erected on the premises or factory assembled.
Excludes:
1. Vessels, heat exchangers, condensers, pumps, compressors, expanders, scrubbers, and other equipment.
2. Vacuum piping systems supply insulating vacuum to vacuum jackets of cryogenic piping systems.
3. Piping systems specifically covered by ASME Codes B31.5 or B31.3 (wording of draft).
ASME Code B31.11: Slurry Piping Systems
Includes:
1. Initial coverage will be coal transported in water.
2. Future coverages will include slurries of other solids transported in nonhazardous liquids.
In industrial piping systems, snubbers, also known as shock absorbers, play a critical role in preventing excessive movement caused by dynamic forces like seismic activity and operational vibrations.