Three novel passive fire shelters designed to protect the vital control electronics of automatic emergency shutdown and fire suppression systems on offshore gas production platforms in the Arabian Gulf are being supplied by the outdoor enclosure specialist Intertec.
Fabricated using lightweight composite glass reinforced polyester (GRP) materials, the shelters employ patented techniques to resist fire for two hours – allowing critical electronic safety equipment to remain operational. Although there are currently no standards for this application area that cover containment temperatures, Intertec designs, manufactures and tests its fire shelters to a rigorous proprietary specification which demands that their internal temperature must remain below 60 degrees C throughout the rated protection time. The novel shelters are also capable of withstanding both conventional and more severe hydrocarbon fires.
All three fire shelters are floor-mounted, ‘walk-in’ models of a style more usually associated with process analyser shelters and are the largest that Intertec has produced to date. They represent a major advance over many current fire protection technologies used in this area, such as fire safe buildings constructed from concrete or steel and covered with fire resistant ceramic tiles, or conventional shelters covered with intumescent materials – which can hinder access. The weight of the composite GRP materials that Intertec uses is about 25% that of steel – for a similar strength – and only 10% that of concrete, making it especially suitable for offshore applications.
Until now, almost all of the fire resistant enclosures Intertec has produced have been in the form of smaller cabinets designed to protect specific critical process control elements of refineries, petrochemical plants and offshore platforms - typically electromechanical emergency shutdown (ESD) valves and actuators. This is the first time that fire shelters have been specified for the even more demanding role of protecting heat-sensitive control system electronics from the direct and indirect effects of fire.
Intertec produces all its fire shelters using a proprietary composite construction technique, comprising one or more layers of fire-resistant mineral wool insulation ‘sandwiched’ between sheets of special-grade GRP. The overall design of the shelters is patented. By changing manufacturing parameters such as the thickness of the GRP walls and the number and type of insulation layers that they contain, the company is able to tailor the material’s composition to provide specific levels of fire resistance.
The fire shelters that Intertec is supplying for this Middle East offshore gas project are designed to withstand fire for 120 minutes, to afford maximum protection to the control electronics of a platform's ESD and fire suppression systems under all foreseeable circumstances. A large outward-opening door provides personnel with unfettered access for routine equipment inspection and maintenance. For air conditioning and ventilation purposes, the shelters are equipped with special fire-resistant air transfer grilles containing intumescent damper slats, that are expressly designed for use in harsh environments. Under normal conditions the grilles allow an unrestricted flow of air into and out of the shelter. However, in the event of a fire, the heat activates the intumescent material which then creates a very durable and insulating barrier against the ingress of flames and hot gases.
For more information visit www.intertec.info