29 C.F.R. § 4.155
The Act, in section 8(b), makes it plain that the coverage of service employees depends on whether their work for the contractor or subcontractor on a covered contract is that of a service employee as defined in section 8(b) and not on any contractual relationship that may be alleged to exist between the contractor or subcontractor and such persons. In other words, any person, except those discussed in § 4.156 below, who performs work called for by a contract or that portion of a contract subject to the Act is, per se, a service employee. Thus, for example, a person's status as an "owner-operator" or an "independent contractor" is immaterial in determining coverage under the Act and all such persons performing the work of service employees must be compensated in accordance with the Act's requirements.
29 C.F.R. §4.155