29 CFR § 778.320 - Hours that would not be hours worked if not paid for.
In some cases an agreement or established practice provides for compensation for hours spent in certain types of activities which would not be regarded as working time under the Act if no compensation were provided. Preliminary and postliminary activities and time spent in eating meals between working hours fall in this category. Compensation for such hours does not convert them into hours worked unless it appears from all the pertinent facts that the parties have treated such time as hours worked. Except for certain activity governed by the Portal-to-Portal Act (see paragraph (b) of this section), the agreement or established practice of the parties will be respected, if reasonable.
(a) Time treated as hours worked. Where the parties have reasonably agreed to include as hours worked time devoted to activities of the type described in the introductory text of this section, payments for such hours will not have the mathematical effect of increasing or decreasing the regular rate of an employee if the hours are compensated at the same rate as other working hours. The requirements of section 7(a) of the Act will be considered to be met where overtime compensation at one and one-half times such rate is paid for the hours so compensated in the workweek which are in excess of the statutory maximum.
(b) Time not treated as hours worked. Under the principles set forth in § 778.319, where the payments are made for time spent in an activity which, if compensable under contract, custom, or practice, is required to be counted as hours worked under the Act by virtue of section 4 of the Portal-to-Portal Act of 1947 (see parts 785 and 790 of this chapter), no agreement by the parties to exclude such compensable time from hours worked would be valid. On the other hand, in the case of time spent in an activity which would not be hours worked under the Act if not compensated and would not become hours worked under the Portal-to-Portal Act even if made compensable by contract, custom, or practice, such time will not be counted as hours worked unless agreement or established practice indicates that the parties have treated the time as hours worked. Such time includes bona fide meal periods, see § 785.19. Unless it appears from all the pertinent facts that the parties have treated such activities as hours worked, payments for such time will be regarded as qualifying for exclusion from the regular rate under the provisions of section 7(e)(2), as explained in §§ 778.216 through 778.224. The payments for such hours cannot, of course, qualify as overtime premiums creditable toward overtime compensation under section 7(h) of the Act.