29 C.F.R. § 553.103

(a) The 1985 Amendments provide that employees may volunteer hours of service to their public employer or agency provided “such services are not the same type of services which the individual is employed to perform for such public agency.” Employees may volunteer their services in one capacity or another without contemplation of pay for services rendered. The phrase “same type of services” means similar or identical services. In general, the Administrator will consider, but not as the only criteria, the duties and other factors contained in the definitions of the 3-digit categories of occupations in the Dictionary of Occupational Titles in determining whether the volunteer activities constitute the “same type of services” as the employment activities. Equally important in such a determination will be the consideration of all the facts and circumstances in a particular case, including whether the volunteer service is closely related to the actual duties performed by or responsibilities assigned to the employee.

(b) An example of an individual performing services which constitute the “same type of services” is a nurse employed by a State hospital who proposes to volunteer to perform nursing services at a State-operated health clinic which does not qualify as a separate public agency as discussed in § 553.102. Similarly, a firefighter cannot volunteer as a firefighter for the same public agency.

(c) Examples of volunteer services which do not constitute the “same type of services” include: A city police officer who volunteers as a part-time referee in a basketball league sponsored by the city; an employee of the city parks department who serves as a volunteer city firefighter; and an office employee of a city hospital or other health care institution who volunteers to spend time with a disabled or elderly person in the same institution during off duty hours as an act of charity.