Definitions.

In this subpart: Administrative workweek means a period of seven consecutive calendar days. Basic workweek for full time employees means the days and hours within an administrative workweek which make up the employee's regularly scheduled 40-hour workweek. Environmental differential means a differential paid for a duty involving unusually severe hazards or working conditions. Irregular or occasional overtime work means overtime work which is not part of the regularly scheduled administrative workweek. Night shift differential means the differential paid the employee when the majority of regularly scheduled nonovertime hours worked fall between 3 p.m. and 8 a.m. Overtime work means authorized and approved hours of work performed by an employee in excess of eight hours in a day or in excess of 40 hours in an administrative workweek, and includes irregular or occasional overtime work and regular overtime work. Premium pay means additional compensation for overtime, or Sunday work, and standby duty. Sunday work means work performed during a regularly scheduled tour of duty within a basic workweek when any part of that work which is not overtime work is performed on Sunday. Regular overtime work means overtime work which is a part of the regularly scheduled administrative workweek. Regularly scheduled administrative workweek means: (1) For full-time employees, the period within an administrative workweek within which employees are scheduled to be on duty regularly. (2) For part-time employees, it means the days and hours within an administrative workweek during which these employees are scheduled to be on duty regularly. Tour of duty means the hours of a day, i.e., a daily tour of duty, and the days of an administrative workweek, i.e., a weekly tour of duty, that are scheduled in advance and during which an employee is required to perform on a regularly recurring basis.