Operating hours means:
(1) For engine and equipment storage areas or facilities, times during which people other than custodians and security personnel are at work near, and can access, a storage area or facility.
(2) For other areas or facilities, times during which an assembly line operates or any of the following activities occurs:
(i) Testing, maintenance, or service accumulation.
(ii) Production or compilation of records.
(iii) Certification testing.
(iv) Translation of designs from the test stage to the production stage.
(v) Engine or equipment manufacture or assembly.
40 CFR § 1068.30
The following definitions apply to this part. The definitions apply to all subparts unless we note otherwise. All undefined terms have the meaning the Clean Air Act gives to them. The definitions follow: