GMC HVAC (GH) provides heating, ventilation and air-cooling (HVAC) systems to the offshore industry, as well as installs ventilation systems for rigs and modules in the Norwegian construction industry.

The company also builds HVAC solutions and bulk materials, and together with the rest of the GMC Group, it offer all related services to deliver complete EPCI projects.

Ductwork systems for the offshore industry

The SIMDUCT® system is developed in-house by GMC HVAC and are available in stainless-steel AISI 316 L in duct classes A, B, C, P and F. It comprises components that are acid and fireproof according to an A0-rating, leading to a long service life and significant savings in spare and replacement parts.

The system and its in-line equipment form a much lighter product than those ordinary galvanized steel sheet structures and carbon steel (Class D) previously / often used offshore, are mounted locally on the rig or platform, and placed directly into the structure carrying the HVAC ductwork.

GMC HVAC installs and supplies climate control solutions, including compact air-handling units, for the offshore industry.
The company creates related components such as heavy-duty diffusers.dampers, hatches, intake hoods, jet hoods, bulk penetration and other in-line equipment.
GMC HVAC’s Class F duct is approved to an A0 fireproof rating.
The firm supplies Data AC units for air-cooling applications.
GMC HVAC’s range of stainless-steel components includes specially designed bends with hatches.

SIMDUCT offers much more flexibility as the duct can easily be adjusted on-site, which leads to less waste of duct, more installation options to the client, and prompt and precise delivery.

Flexible climate control solutions for enclosed spaces

GH develops the flexible SIMVENT® solution, which controls the climate conditions in drilling cabins, adjacent local equipment rooms (LER) and local instrument rooms (LIR) on onshore and offshore facilities.

The company produces ventilation ducts and in-line equipment in AISI 316L stainless-steel, creating an acidproof, Spiro ventilation system, according to NORSOK and ISO 15138. It is fire and pressure-tested to comply with IMO standard res. A.754 (18), and verified by DNV and ABS.

Benefits of using Class A, B, C, P and F ducts

GMC HVAC offers a number of advantages of using these ducts, which include:

  • Significant weight reduction, up to 70% more than conventional systems
  • Lower installation time and costs, with a reduction of up to 40%
  • No lifecycle cost: lasts for the entire lifetime of the module / platform
  • Less pressure drop than conventional systems (energy reduction)
  • Less vibrations and noise, and better airflow / air velocity in the duct system (HSE)
  • More sturdy and robust compared with rectangular duct in the same duct class
  • Standardised support system to be used together with Øgland MultiGrid / support system

The company’s latest innovations are a new type of duct called the Class P (Pressure), rated on 7 bar internal / external water pressure. The duct system is intended to be used in shafts, hull and pontoons on semi-submersible platforms, as well as marine and petrochemical installations.


GMC HVAC’s technical department contains a workforce of engineers and technicians that form project teams for each different order.

The company is capable of executing small and medium-sized engineering, procurement, construction and installation (EPCI) projects, handling all aspects of design and engineering, material selection, construction design, procurement, project management and project execution.