Trades License Verification
How to Verify a Boiler Operator or Stationary Engineer License
Boiler operators and stationary engineers who operate high-pressure boilers and pressure vessels must hold state-issued licenses in most jurisdictions. License grades vary by boiler pressure capacity and plant complexity. Here is how to verify.
Quick answer
Boiler operator and stationary engineer licenses are state-issued. Verify through the state boiler or pressure vessel inspection program — typically within the state Department of Labor or Department of Public Safety. There is no national database. Contact the state boiler program directly or use the state's online license lookup if available.
How boiler operator licensing works
Boiler and pressure vessel operation is regulated under state law in most U.S. jurisdictions. States that follow the ASME Boiler and Pressure Vessel Code require operators of high-pressure boilers to hold a state license issued after passing written exams and demonstrating boiler operating experience.
License grades vary by state but generally follow this pattern:
| Grade / Class | Typical Scope |
|---|---|
| Low-pressure or Class D / Grade 4 | Low-pressure steam and hot water heating boilers; entry-level |
| High-pressure or Class C / Grade 3 | High-pressure steam boilers up to a certain horsepower or BTU rating |
| First Class or Grade 1 / Unlimited | Unlimited horsepower; required for large industrial plants and power stations |
| Special / Refrigeration | Refrigeration systems, HVAC chillers, and ammonia systems — required in some states |
Grade naming conventions differ significantly by state. Minnesota uses “First Class,” “Second Class,” etc. New York uses “High Pressure” and “Low Pressure.” Confirm the license grade terminology for the specific state before verifying.
State boiler program verification
Each state's boiler inspection program is the authoritative source for operator license verification. Most provide phone or online verification:
State boiler program contacts
- Minnesota: Dept. of Labor and Industry, Boiler Section — dli.mn.gov/boiler (online license lookup)
- New York: Dept. of Labor, Bureau of Boiler and Pressure Vessel — labor.ny.gov
- New Jersey: Dept. of Community Affairs, Bureau of Boiler and Pressure Vessel Compliance — nj.gov/dca/divisions/codes
- California: Dept. of Industrial Relations, Division of Occupational Safety and Health (Cal/OSHA) — dir.ca.gov
- Pennsylvania: Dept. of Labor and Industry, Bureau of Occupational and Industrial Safety — dli.pa.gov
- All states: National Board of Boiler and Pressure Vessel Inspectors (NB) at nationalboard.org maintains state boiler program contacts
National Board commission
The National Board of Boiler and Pressure Vessel Inspectors (NB) is not a licensing body for operators — it issues inspector commissions to boiler inspectors (the people who inspect boilers, not who operate them). However, the NB is the authoritative body for boiler codes (NBIC) and maintains a directory of state boiler programs at nationalboard.org.
If you are verifying a boiler inspector (rather than a boiler operator), the NB commission is the relevant credential — verify through the NB directly.
IUOE and union certifications
Many stationary engineers are members of the International Union of Operating Engineers (IUOE). Union membership and IUOE training completion are separate from state licensing — both may be relevant for unionized facility roles. Union training completion records are held by the IUOE local union, not publicly searchable.
Red flags
- Operator cannot provide a state license number for the state where the boiler is located
- License grade insufficient for the boiler capacity at the facility — verify the license grade covers the boiler horsepower or BTU rating
- Expired state license — renewal periods vary by state (typically 1–3 years)
- No state license when operating in a state that requires operator licensure for the boiler type in use
Verification checklist
- 1. Identify the state where the boiler is located and the boiler's pressure class or horsepower rating
- 2. Contact the state boiler inspection program and request license verification for the operator
- 3. Confirm the license grade is sufficient for the boiler type and capacity at the facility
- 4. Confirm the license is current and not expired
- 5. For refrigeration or chiller systems: confirm separate refrigeration operator license if required by the state
Verify stationary engineering program accreditation
Stationary engineers and boiler operators often complete vocational programs at community colleges or trade schools. Use VerifyED to confirm whether a training program is accredited.
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