CPV Unveils Pioneering District Heating Pipe

CPV Ltd has unveiled the next generation of district heating pipe systems, with the launch of an innovative product that offers a service pipe that has none of the corrosion risk associated with steel systems, yet it’s able to cope with higher temperatures and pressures that would be beyond the normal safe limits of polymer-based pipe systems.

Called Hiline GRE, the new pipe system incorporates a service pipe constructed from a rigid composite glass reinforced epoxy (GRE) that’s encased with an efficient layer of bonded polyurethane (PUR) foam and a protective outer casing of HDPE.

Available with service pipe dimensions from DN50mm up to DN500mm, it’s suitable for operating temperatures up to 120°C at 10 bar – making it ideal for both LTHW and MTHW heating along with lower temperature applications such as cooling. Being a bonded system, the tough HDPE outer casing is bonded to the GRE service pipe by a layer of closed-cell polyurethane foam insulation – allowing the pipe to expand and contract as one. This, unlike systems with an air gap, offers greater reliability and much improved thermal efficiency – which results in lower operating costs and significantly reduced carbon emissions.

Mark Whettall, managing director commented: “With the district heating sector expanding so rapidly, system owners and developers are looking for greater levels of reliability and choosing a pre-insulated pipe system with a GRE service pipe will do just that.”

“Although if designed, installed, operated and maintained correctly, a steel pipe system will offer long service life, the risk of corrosion is always present – especially if the outer casing gets damaged and ground water ingresses into the insulation. Using alternative such as a composite glass reinforced epoxy, the corrosion risk is eliminated and reliability levels significantly increased.

“We’ve found that when using Hiline GRE in sizes DN200/250mm and above, the materials actually start to show a cost advantage over similar sized pre-insulated steel systems, which further adds to their appeal.

“As long as they are designed and installed correctly and operated within their safe temperatures and pressures, it’s pretty-much a ‘fit-and-forget’ solution.”

Hiline GRE Joint CutawayThe new pipe system is easy to join and uses an adhesive-bonded tapered spigot and socket method that provides secure joints that will outlast the long operational life of the pipe system. The outer casing and insulation are joined with the proven range of Hiline casing joints that include wrap-around heat shrink or electro-fusion couplings to ensure the tightest of joints to maintain the integrity of the foam insulation.

With the GRE pipe being lighter than its steel equivalent, both safety and ease of handling is improved during transportation and installation. Both the weight and method of manufacturer also have a positive impact on the carbon footprint for the service pipe when compared to steel.

In addition to the new Hiline GRE system, CPV has also developed a number of other service pipe options that offer an alternative to steel, such as Hiline Flex – a flexible cross-linked polyethylene (PEX) system and Hiline Aqua – a bonded rigid polymer composite pre-insulated pipe system that’s been specifically designed to replace steel systems in networks operating up to 95°C.

Installation is also much easier with Hiline Aqua than with steel systems as, not only is the pipe lighter, but it is simple to cut and being a thermoplastic it’s joined with a selection of fusion welding techniques, including electro-fusion, butt welding and socket-fusion methods.

“We’re getting a lot of interest for these systems, particularly from network owners and developers that have previously had bad experiences with corrosion of steel systems. With our additional support services, such as design and engineering support, we are able to ensure that quality levels remain high and the recently introduced CIBSE Code of Practice for heat networks is adhered to” concluded Whettall.