The head of each agency, with respect to each full-time employee to whom this subpart applies, shall establish by a written agency policy statement:

A basic workweek of 40 hours which does not extend over more than 6 of any 7 consecutive days. Except as provided in paragraphs (b), (c), and (d) of this section, the written agency policy statement shall specify the days and hours within the administrative workweek that constitute the basic workweek.

A regularly scheduled administrative workweek that consists of the 40-hour basic workweek established in accordance with paragraph (a)(1) of this section, plus the period of regular overtime work, if any, required of each employee. Except as provided in paragraphs (b), (c), and (d) of this section, the written agency policy statement, for purposes of leave and overtime pay administration, shall specify by days and hours of each day the periods included in the regularly scheduled administrative workweek that do not constitute a part of the basic workweek.

When it is impracticable to prescribe a regular schedule of definite hours of duty for each workday of a regularly scheduled administrative workweek, the head of an agency may establish the first 40 hours of duty performed within a period of not more than 6 days of the administrative workweek as the basic workweek. A first 40-hour tour of duty is the basic workweek without the requirement for specific days and hours within the administrative workweek. All work performed by an employee within the first 40 hours is considered regularly scheduled work for premium pay and hours of duty purposes. Any additional hours of officially ordered or approved work within the administrative workweek are overtime work.

(1) When an employee is paid additional pay under section 5545(c)(1) of title 5, United States Code, his regularly scheduled administrative workweek is the total number of regularly scheduled hours of duty a week.

When an employee has a tour of duty which includes a period during which he remains at or within the confines of his station in a standby status rather than performing actual work his regularly scheduled administrative workweek is the total number of regularly scheduled hours of duty a week, including time in a standby status except that allowed for sleep and meals by a written agency policy statement.

When the head of an agency establishes a flexible or compressed work schedule under section 6122 or section 6127 of title 5, United States Code, he or she shall establish a basic work requirement for each employee as defined in section 6121 of title 5, United States Code. A flexible or compressed work schedule is a scheduled tour of duty and all work performed by an employee within the basic work requirement is considered regularly scheduled work for premium pay and hours of duty purposes.