Exemptions from part.

Nothing in this part shall be construed to affect or prevent the following:

(1) The practice of engineering by any person who, within 1 year after September 19, 1950, has filed with the Board an application for registration under this part. This exemption shall continue only for such time as the Board may require for consideration of said application;

(2) The practice of engineering for not exceeding 30 days in the aggregate in 1 calendar year by a nonresident not having a place of business in the District of Columbia, if such person is licensed or registered to engage in the practice of engineering in a state or territory in which the requirements and qualifications for obtaining a license or registration are reasonably equivalent to those specified in this part;

(3) The practice of engineering for more than 30 days by a nonresident not having a place of business in the District of Columbia, or by a person who has recently become a resident of or has recently entered the practice of engineering in the District of Columbia, and who has filed with the Board an application for registration, if such person is registered or licensed to engage in the practice of engineering in a state or territory in which the requirements and qualifications for obtaining a license or registration are reasonably equivalent to those specified in this part. Such practice shall be permitted only for such time as the Board requires for the consideration of the application;

(4) The performance of engineering work by any person who acts under the supervision of a professional engineer, or by an employee of a person lawfully engaged in the practice of engineering, and who, in either event, does not assume responsible charge of design or supervision;

(5) The practice of engineering as a consultant, officer, or employee of the government of the United States or the government of the District of Columbia while engaged solely in such practice for said governments;

(6) The practice of any other legally recognized profession;

(7) The practice of engineering exclusively as an officer or employee of a public utility corporation by rendering to such corporation such service in connection with its facilities and property which are subject to supervision with respect to safety and security thereof by the Public Service Commission of the District of Columbia and so long as such person is thus actually and exclusively employed and no longer; provided, however, that each such public utility corporation shall employ at least 1 registered professional engineer who shall be in responsible charge of such engineering work;

(8) The practice of architecture by a person authorized to use the title of architect or registered architect under the provisions of Chapter 16 of Title 3 , and his doing such engineering work as is incidental to his architectural work;

(9) The construction or alteration of a building that does not cover over 1,000 square feet of ground area and does not have a height of over 20 feet to the uppermost ceiling, or 2 habitable floors above a basement;

(10) The execution of construction work as a contractor, or the superintendence of such construction work as a foreman or superintendent, or the work performed as a salesman of engineering equipment or apparatus;

(11) The operation or maintenance of boilers, machinery, or equipment when the operators are duly licensed under the provisions of Chapter 27 [repealed] of Title 3; or

(12) The usual supervision of construction or installation of equipment within a plant under his immediate supervision by a person ordinarily designated as supervising engineer or chief engineer of power.