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The Bullet-Proof Choice for District Heating

CPV Ltd, a leading district heating pipe manufacturer, has launched an innovative new range of flexible pre-insulated pipe systems with reinforced polymer service pipes that improve thermal efficiency and provide higher factors of safety.

With the ability to increase the operating temperature and pressure closer to that of traditional steel systems – as high as a constant 95°C at 16 bar pressure and with excursions up to 115°C – a greater factor of safety can be introduced which will give district heating network owners and operators greater confidence in their systems’ reliability, with the added benefit of improved thermal performance and no risk of corrosion.

FibreFlexPro 600x400bThese new reinforced options, known as Hiline FibreFlex and FibreFlex Pro, form a key part of an update to the existing Hiline range, a system of district heating pipe systems offered by the UK’s longest-serving pre-insulated pipe manufacturer, CPV Ltd.

With three flexible polymer service pipe options now available, all feature a composite polymer service pipe that is encased inside a highly-efficient bonded layer of polyurethane foam insulation, which in turn is protected by a tough corrugated outer casing of LDPE.

Hiline e-Flex is the entry-level system with a composite PE-Xa service pipe and oxygen diffusion barrier suitable for constant operation at 80°C and 6 bar pressure. The two reinforced service pipe options, Hiline FibreFlex and FibreFlex Pro, cleverly incorporate an aramid mesh – a material commonly used in bullet-proof vests - in a composite service pipe construction that not only enable the systems to withstand higher temperatures and pressures, than conventional PEX systems, but also, they have a reduced wall thickness that provides additional space for an increased thickness of insulation. This has the dual benefit of improving thermal performance and making the systems more flexible than their PE-Xa-only counterparts.

All Hiline Flex systems can be supplied in dimensions ranging from 25mm up to 160mm OD - with both single and twin service pipe configurations, delivered to site in continuous lengths on coils, to minimise on-site jointing and speed-up installation times.

Hiline e-Flex, Hiline FibreFlex and FibreFlex Pro pipe options are offered with a complete range of joints, fittings, valves and accessories that ensure not only a speedy installation, but a long lifetime of efficient and reliable operation.

fibreflex assorted fittings 900x600Mark Whettall, CPV’s managing director, commented: “Whilst a traditional steel pre-insulated pipe system can offer reliable performance if installed, operated and maintained correctly, there is always the inherent risk of corrosion and deterioration of the systems’ efficiency over time.”

“Alternatively, the Hiline FibreFlex and FibreFlex Pro options provide a perfect complement to conventional pre-insulated steel pipe networks as a hybrid solution, offering greater routing flexibility, reduced installation costs and lower heat losses.

“Pre-insulated, flexible polymer pipe systems have, in recent years, become the norm for most smaller district heating networks – largely for their non-corrosive service pipes and simple installation, but the conventional polymer service pipes such as PEX are working at the higher end of their safe limits in terms of the typical temperatures and pressures employed.

“By introducing a service pipe with a reinforced composite construction that brings together the advantages of a PE-Xa pipe with outstanding performance characteristics of the aramid fibres – a super-strong material that’s renowned for its ability to withstand heat – we can produce a district heating pipe system that has the very best of both worlds and afford system owners with the highest levels of reliability.”

With the closed-cell bonded PUR foam insulation having a lambda value of around 0.0210 W/mK and a greater thickness permitted by the reduced wall thickness, the level of heat loss from the reinforced FibreFlex and Fibre Flex Pro systems will be significantly lower than alternative systems using a conventional polymer service pipe material.

fibreflexPro S1 3GraphWhettall continued: “When comparing our FibreFlex pipes to that of typical pre-insulated PEX systems, the FibreFlex pipes were found to have at least a 17-per-cent lower heat loss. It also outperforms pre-insulated steel with Series 2 insulation and is comparable to Series 3 up to 80mm diameter – which over a system’s operating life extending to decades, the impact in both financial and environmental terms is huge and can make all the difference to a system’s viability.” 


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