The Director is authorized, subject to the civil service laws, to appoint such clerical and other personnel as may be necessary for the execution of the functions of the Service, and shall fix their compensation in accordance with chapter
51 and subchapter
III of chapter
53 of title
5, and may, without regard to the provisions of the civil service laws, appoint such conciliators and mediators as may be necessary to carry out the functions of the Service. The Director is authorized to make such expenditures for supplies, facilities, and services as he deems necessary. Such expenditures shall be allowed and paid upon presentation of itemized vouchers therefor approved by the Director or by any employee designated by him for that purpose.