Cable protection for rail applications
Ralf Tigges, Sales Manager for West, North and North-East Germanay at Anamet Europe is bending a conduit with a black, extruded cover. “This is a highly flexible metal hose type.”
Conduits of the Anaconda Multitite product group are extruded with thinner walls than the Anaconda Sealtite range and thus fulfill extremely small bending radii. “If the installation specifies or offers the possibility of larger bending radius, Anaconda Sealtite with its thicker wall could be a better solution. Depending on the certification and specification requirements of the application, we extrude the metal hose with polyurethane or polyolefin plastic for various rail applications”.
Anaconda! In the movie of the same name of 1997, it is not only a giant snake, but a bloodthirsty beast that kills humans, which is defeated by Jennifer Lopez at the last moment. Anamet Europe has also „Anacondas“ in its product portfolio – but these do not attack, they protect.
Extrusion, that is the continuous melting of viscous plastics under pressure with the help of a shaping nozzle, a process that bonds the plastic with the bare hose. The choice of materials for extrusion depends on the required hazard level (HL) according to the EN 45545-2 standard for rail in combination with the Operating Category (OC) of the train and circumstances which it runs. The Hazard Level is in essence determined by the duration that passengers in a rail vehicle are exposed in the case of fire. There are three Hazard Levels: HL 1, HL 2 and HL 3. That is the reason that HL 3 – which is achieved by the use of special polyolefins – is required if vehicles are planned to operate in, for example, long tunnels. Thus, the higher the danger, the higher the HL class.
Why are such systems needed? Isn’t it enough to install the different cables in a rail vehicle directly without such a protection? Not at all, explains Anamet expert Ralf Tigges. „We provide robust cable protection systems for the rail industry, certified according to European standards or the specifications of other recipient countries. Such protection is required especially under the bogie of the vehicles. There the cables have to be protected against wide fluctuations in temperature and humidity; under these conditions the protective cover has to retain its flexibility and also has to mechanically protect against stone splash, ice accumulation, wind and sand abrasion etc., as well.“
Mechanical impact resistance, that makes sense. What else has to be taken into account? „If there is no need for a liquid-tight conduit, also a metal conduit can be used. Of course this is a cheaper solution because there is no requirement for a certification in conformity with fire protection standards.“ However, it is not a solution when a higher ingress protection is specified, for example, IP67.
When using plastic, every component, and indeed the entire product itself, has to meet the standards for fire protection, smoke and toxicity. “Take for example cable hose fittings – they are available with a 90 or 45° angle, with PG, ISO or NPT thread… If we install a fitting with strain relief of the hose, then every single seal has to be tested for fire resistance as well.“ And who comes up with this variety? Aren’t the basic versions sufficient for the vehicle manufacturers? “The requirements for the installation inside and outside a vehicle – and depending on the HL-class – are so different, that we will expand our product portfolio to meet the requirements of the application “, stresses Tigges. More and more components have to be installed on the vehicle in the smallest space – but some necessities just arise during the running operation of the vehicles. “This is why we develop special solutions for the applications together with the engineers of the vehicle manufacturers and the operators.“ Heat protection is a topic which grows more and more in importance. Tigges emphasizes this on the example of a flexible hose in reddish colour called Hiprojacket. “Such a cover protects the cable even in extreme heat for a long period of time. In one project we have created a solution that protects important data communication and power cables against molotov cocktail attacks. The user has simulated a 15 minute test at a constantly rising temperature up to 800°C. The functional integrity of the cable was thus ensured.“
Do you have a question about our metal hoses and fittings? Contact our customer service directly by phone: +31-20-5863586 or by email: firstname.lastname@example.org.