An Australian-manufactured electrical and safety conduit that is many times lighter and easier to install than metal conduit has achieved one of its first major infrastructure uses.
CalAir’s HFT polymer conduit, with halogen-free flame retardant properties, has been selected by the United Group for the Epping to Chatswood rail line in Sydney.
About 2.5 kilometres of the new product is being used to carry electrical services from one side of the tunnels to the other, with the tough flexible conduit conforming to the semi-circular arc of the tunnel crown.
The difficulty with metal pipe in tunnels is that it has to be bent to conform with the radius, presenting installation difficulties as well as OH and S issues, where personnel have to cope with the greater weight of the material being manoeuvred. Naturally there are also corrosion issues where steel is used, particularly in aggressive environments.
CalAir introduced its halogen free flame retardant polymer conduit as an alternative to imported systems typically costing more than twice as much. In addition to carrying electrical cabling, it can be used within safety equipment such as aspiration systems and air sampling systems that to protect against smoke and toxicity.
Now available in diameters from 20 – 110mm in response to demand in Australia and New Zealand, the conduit is especially formulated to meet high fire safety requirements in surface and sub-surface applications. Two sizes are involved in the rail link project:
* 90mm outside diameter (80mm inside diameter) 1.34km
* 63mm outside diameter (55mm inside diameter) 1.19km
Producing no corrosive or toxic flue gases in the event of a fire, the halogen free low smoke, range of polymer conduit is designed for use in situations where there are high concentrations of people, high concentrations of assets or risk of high costs due to production interruption.
The halogen free low smoke applications include advanced technology industrial and manufacturing plants, mines, tunnels, airports, subway systems, power plants, oil refineries, lifts, emergency plants, ships, aircraft, trains, computer and telecommunication installations. The halogen free low smoke can also be used in hospitals, schools, hotels, museums, theatres, shopping centres and conference centres.
The new conduit is the result of an extensive research and development programme designed to overcome hurdles in producing flame-retardant pipe and conduit without degrading their overall performance, including impact resistance or pressure capability. The HFT conduit is complemented by both standard glued type fittings or high performance IP67 fittings.
What is particularly important in applications such as the Epping to Chatswood rail line tunnel is ease of use in situations that can sometimes offer limited access within fairly restricted production schedules. With this system there is no need to have to bring in a variety of trades to handle it, the whole system is designed for radically simplified erection, disassembly and recycling within a fraction of the time taken to construct and change traditional metal alternative conduits.
Weighing just one eighth the weight of galvanised steel, for example, it can be easily installed with far fewer OHS issues than heavier materials. Also, its flexibility enables it to confirm readily to irregular contours, such as those encountered in tunnels and trenches. This flexibility and ease of installation can produce considerable savings.
Properties of the new HFT range include:
* No fire transmission or fire propagation
* Low density and minimal formation of flue gases in the event of a fire
* High temperature resistance
* Low toxicity, non corrosive
* High impact properties and stiffness
* Excellent electrical and dielectrical properties
* Available in sizes 20-110mm
The range is manufactured to the same standards of durability and quality as CalAir gas and liquid pipe systems used in 6,500 applications in Australia and internationally.