In this Chapter, unless the context otherwise requires,
(39a) "erection, commissioning or installation" means any service provided by a commissioning and installation agency, in relation to,-
(i) erection, commissioning or installation of plant, machinery equipment or structures, whether pre-fabricated or otherwise ; or
(ii) installation of-
(a) electrical and electronic devices, including wirings or fittings therefor; or
(b) plumbing, drain laying or other installations for transport of fluids; or
(c) heating, ventilation or air-conditioning including related pipe work, duct work and sheet metal work; or
(d) thermal insulation, sound insulation, fire proofing or water proofing; or
(e) lift and escalator, fire escape staircases or travelators; or
(f) such other similar services;