District of Columbia Code Division I. Government of District. § 2-109. Exemptions.

Steam boilers and unfired pressure vessels located in or upon boats or vessels or other floating equipment, or boats or vessels owned or operated by the United States, or upon locomotives, street cars, busses, or other vehicles, operated under the regulations of any federal agency or the Public Service Commission of the District of Columbia, shall be exempt from the provisions of this subchapter.