ASME Boiler & Pressure Vessel Code
Boilers and pressure vessels hold fluid under pressure, and when they fail they can explode with deadly force. The ASME Boiler and Pressure Vessel Code (BPVC), published by the American Society of Mechanical Engineers, sets rules for designing, building, testing and inspecting them. Most states and many cities adopt it into law, and OSHA and insurers rely on it as a recognized standard.
- Stationary Engineers
- Boiler Operators
- Maintenance Techs
- Inspectors
- Plant Managers
What the Code covers
| Section | Topic |
|---|---|
| Section I | Power boilers (steam boilers and high-temperature water boilers) |
| Section IV | Heating boilers (low-pressure steam and hot water for building heat) |
| Section VIII | Pressure vessels (Divisions 1, 2 and 3: tanks, reactors, heat exchangers, air receivers) |
| Section II | Materials |
| Section V | Nondestructive examination (such as radiography and ultrasonic testing) |
| Section IX | Welding, brazing and fusing qualifications (procedures and welders) |
| Section VII | Recommended guidelines for care of power boilers |
| Section X, XII and others | Fiber-reinforced plastic vessels, transport tanks and related topics |
Piping is covered by the separate ASME B31 series. Boiler controls and safety devices are covered by ASME CSD-1 (controls and safety devices for automatically fired boilers). See Boilers & Pressure Vessels and Steam Systems.
Code stamps and nameplates
- Manufacturers who meet ASME requirements get Certificates of Authorization to apply code symbol stamps such as S (power boilers), H (heating boilers), U (pressure vessels) and V (safety valves) to equipment they build.
- A boiler or vessel built to the Code carries a nameplate with the stamp, manufacturer, serial number, maximum allowable working pressure (MAWP), design temperature and year built. Don't remove or cover it.
- Equipment is registered with the National Board of Boiler and Pressure Vessel Inspectors and given a National Board number, which helps track inspection and repair history.
- Repairs and alterations must be done by qualified firms authorized by the National Board “R” stamp, following the National Board Inspection Code (NBIC).
Inspection and legal requirements
- State and local boiler laws usually require registration, periodic inspection (often annually for power boilers and every 1 to 2 years for others) and certificates of operation, enforced by a chief boiler inspector or insurer's inspectors. Rules differ by jurisdiction. See Permits & Inspections.
- OSHA requires safe operation and maintenance of boilers and pressure vessels and cites ASME and other consensus standards under the General Duty Clause, and has specific rules for unfired pressure vessels (29 CFR 1910.106 and 1910.169) and others. See General Industry (1910).
- Insurers and jurisdictions often require inspections of safety relief valves, low-water cutoffs, gauges and controls.
- Use only licensed operators where the jurisdiction requires them. See Stationary Engineers.
Safety devices to know
- Pressure relief (safety) valves: must be sized, set and stamped to the Code, never plugged, gagged or changed, tested by the schedule and discharge piped safely. Don't isolate a relief valve from its vessel.
- Low-water cutoffs and water gauges: prevent boiler damage and explosions from low water. Test and blow down as the maker and the Code require.
- Pressure gauges and controls: accurate, calibrated and visible. Burner management systems shut off fuel on flame failure and purge the furnace before ignition. See Gas Detectors for gas hazards and CSD-1 for controls.
- Stop valves, check valves, blowdown systems and drains built and maintained properly.
What workers should know
- Never operate a boiler or vessel above its MAWP, bypass safety devices or disable alarms and interlocks.
- Follow operating, startup, shutdown and blowdown procedures, and lockout/tagout when working on them. See Group Lockout and Permit to Work.
- Welding and repairs on pressure parts must follow the Code and be done by qualified, certified welders and authorized firms. Don't weld on a pressure vessel or boiler without approval. See AWS Welding Codes.
- Entering a boiler or vessel is a confined space entry. See Confined Spaces.
- Report leaks, cracks, bulges, corrosion, overheated areas, relief valve discharge and unusual noises, and take defective equipment out of service. Keep records of inspections and repairs.
- Look for inspection certificates posted on or near boilers, and don't use equipment with an expired certificate.
ASME boiler code checklist
- The boiler or vessel has a legible ASME and National Board nameplate
- It's registered and inspected as the jurisdiction requires, with a current certificate
- Relief valves, low-water cutoffs and gauges are tested and never bypassed
- Repairs and welding are done by authorized firms and certified welders
- I report leaks, bulges or abnormal conditions right away and lock out before servicing
Standards & references
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