The majority of stationary engineers are trained through a mixture of on-the-job training and apprenticeship instruction, according to the Bureau of Labor Statistics. Subjects covered by apprenticeship programs offered by the International Union of Operating Engineers include boiler operation and maintenance, energy conservation, and indoor air quality.
To become a state certified stationary engineer, candidates usually must be 18 years of age or older and reside in the state in which they are applying for licensure. The majority of states have work experience requirements and require that candidates pass a written exam.
States offering stationary engineer certification offer a number of grades of certification in specific types and sizes of equipment. For example, the Maryland Department of Labor offers five grades of licensure from grade 1 for 500 horsepower equipment in any building to grade 5, which allows engineers to operate equipment between 30 and 99 horsepower in buildings not for public use.