• • • CABLING & CABLE MANAGEMENT • • •


Protecting vital cable infrastructure from corrosion


Failure to protect power and or data cabling in areas with the potential risk of explosion can be catastrophic for safety and operational efficiency, says Alex Smith, technical director at flexible conduit manufacturer Flexicon


H


azardous areas, by their nature, present many risks and depending on the application the hazards faced can


vary enormously. In order to select appropriate systems that


ensure continuous operation, businesses should consider carefully the range of environmental hazards which cabling may be exposed to and specify a protective solution which has been purpose-designed for the application. Exposure to water ingress, UV radiation, and


extreme temperatures are commonplace in hazardous environments and the effects of these can result in premature product failure, which in turn leads to increased downtime and operating costs. If specified correctly, a combination of


liquid-tight, flexible conduit systems and flameproof barrier glands can offer effective cable protection. These systems are available in nickel- plated brass and 316 stainless-steel, with the suitability of the material dependant on the installation environment. But one particular hazard is often


underestimated when specifying for hazardous locations – the corrosive effect of salt water. Marine vessels and offshore platforms are exposed to this hazard for extended periods of time and therefore its effect needs to be factored in to any cable protection system from the outset.


Dezincification In the presence of salt water, incorrectly-specified, flexible conduit systems could suffer from a process known as dezincification. Dezincification is a process of degradation that


occurs in brass with a zinc content of over 12%. It removes the zinc content from the alloy, leaving behind a porous, copper-rich structure with little mechanical strength. Systems subject to dezincification are unable to provide suitable protection against external hazards including water ingress, impact and crushing. The best solution for cable protection in


hazardous areas exposed to salt water would be a liquid-tight, flexible conduit system utilising stainless steel fittings and glands. Specifically, this offers the best combination of high mechanical strength and ingress protection while providing high levels of chemical and corrosion resistance.


Though there are different grades of stainless


steel used for such applications, the most suitable alloy is marine grade 316L stainless steel. It consists of iron combined with 16-18% chromium, 10-14% nickel, and, crucially, 2-3% molybdenum. This comparatively high level of molybdenum allows for higher corrosion resistance.


Adhering to the standards Flexicon standardises on the use of marine grade stainless steel 316L for both its flexible conduit and flameproof barrier gland systems suitable for hazardous locations. Such systems have been subjected to corrosive salt spray testing to ASTM B117-11 and BS EN ISO 9227 standards.


“ Businesses should


consider carefully the range of environmental hazards


These standards are the benchmark for


establishing corrosion resistance and are often quoted by manufacturers when referring to their products. However, it must be noted that these standards do not establish set periods in which systems should be exposed to salt spray testing. This means that in hazardous environments, the performance of products that ostensibly adhere to ASTM B117-11 and BS EN ISO 9227 may actually vary considerably. To ensure its solutions offer the highest levels


of protection, Flexicon has tested a range of products to 1000 hours of salt spray testing, including the FSS and LTPSS flexible conduit ranges. This testing is carried out by an independent, third-party testing laboratory to ensure maximum possible accuracy. Systems that can withstand this level of


hostile testing with only minimal corrosion and without compromise are typically manufactured exclusively using Grade 316L stainless-steel to ensure best possible performance. Flexicon’s range of flameproof barrier cable glands have been tested and certified to ATEX, IEC Ex and Russian EAC standards, providing customers with the ultimate assurance for cable protection in hazardous locations. Flexicon also offers a specification guide,


featuring different cable protection solutions for use in hazardous areas. The guide makes it easy to specify a system of both conduit and gland or fitting to provide the right level of protection.


10 ELECTRICAL ENGINEERING • NOVEMBER 2021 electricalengineeringmagazine.co.uk ”


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