A modular apparatus for electric induction heating or coating of an exterior surface of a pipe, or for the combination of electric induction heating and coating of the exterior surface of the pipe, the modular apparatus comprising: an interchangeable central main frame assembly, the interchangeable central main frame assembly comprising a central top drive frame assembly and a coil main frame assembly, the central top drive frame assembly disposed above the coil main frame assembly, the central top drive frame assembly comprising a coating system driver and a coil main frame assembly driver system for moving the coil main frame assembly between a closed coil main frame assembly position when the coil main frame assembly forms an encircling closed coil main frame assembly around an axial section of the pipe in a pipe treatment region and an opened coil main frame assembly position when the coil main frame assembly forms an opening for the entry or exit of the axial section of the pipe to or from the pipe treatment region; a coil assembly mounting structure located on the coil main frame assembly; a first and a second side outer drive frame assemblies, the first and second side outer drive frame assemblies respectively and removably connected to a first and second sides of the interchangeable central main frame assembly whereby the axial section of the pipe can pass through the first side outer drive frame assembly, the pipe treatment region of the encircling closed coil main frame assembly and the second side outer drive frame assembly, the first and second side outer drive frame assemblies detachable from the interchangeable central main frame assembly for replacement of the interchangeable central main frame assembly for use with the first and second side outer drive frame assemblies to form a modified pipe treatment region; and a first and second coating head mounting structures located respectively in the first and second side outer drive frame assemblies, the first and second coating head mounting structures connected respectively to a first and second coating head drive assembly (406, 408) located respectively in the first and second side outer drive frame assemblies, the first and second coating head drive assemblies connected to the coating system driver. an interchangeable central main frame assembly, the interchangeable central main frame assembly comprising a central top drive frame assembly and a coil main frame assembly, the central top drive frame assembly disposed above the coil main frame assembly, the central top drive frame assembly comprising a coating system driver and a coil main frame assembly driver system for moving the coil main frame assembly between a closed coil main frame assembly position when the coil main frame assembly forms an encircling closed coil main frame assembly around an axial section of the pipe in a pipe treatment region and an opened coil main frame assembly position when the coil main frame assembly forms an opening for the entry or exit of the axial section of the pipe to or from the pipe treatment region; a coil assembly mounting structure located on the coil main frame assembly; a first and a second side outer drive frame assemblies, the first and second side outer drive frame assemblies respectively and removably connected to a first and second sides of the interchangeable central main frame assembly whereby the axial section of the pipe can pass through the first side outer drive frame assembly, the pipe treatment region of the encircling closed coil main frame assembly and the second side outer drive frame assembly, the first and second side outer drive frame assemblies detachable from the interchangeable central main frame assembly for replacement of the interchangeable central main frame assembly for use with the first and second side outer drive frame assemblies to form a modified pipe treatment region; and a first and second coating head mounting structures located respectively in the first and second side outer drive frame assemblies, the first and second coating head mounting structures connected respectively to a first and second coating head drive assembly (406, 408) located respectively in the first and second side outer drive frame assemblies, the first and second coating head drive assemblies connected to the coating system driver.