Steve Richmond, Head of Marketing and Technical at REHAU Building Solutions, delves into the challenges and considerations for contractors in using polymer pipework and high-quality insulating foam for low-carbon district heating networks.
Free of context, 17 is not a big number. But for UK district heating networks, it represents a significant challenge. As a percentage, this is the figure that must be bridged to meet country-wide ambitions for more sustainable heating. According to government statistics, district heating represented a 3% share of the total heat market in 2022 – far behind the 20% share planned for 2050.
Yet the UK district heating market will be key to the Net Zero transition, with significant investment expected to achieve this goal, especially with the government also dramatically raising housebuilding targets. Similarly, the introduction of the Future Homes Standard banning gas boilers in newbuilds will also move developers towards low-carbon heating and hot water alternatives, including fourth-generation district heating networks.
Polymer pipes are increasingly being used in fourth-generation heat networks, due to their ease of installation and reduced jointing needs. Unlike steel, which is durable but prone to corrosion, polymer systems like REHAU’s RAUVIPEX are non-corrosive, therefore offering long-term reliability. Featuring an integrated water barrier and compatible with jointing systems such as REHAU’s EVERLOC, RAUVIPEX also helps avoid delays linked to the construction skills shortage by eliminating the need for specialist welders.
Mixing safety into every step
As district heating is a relatively new industry compared to gas mains installation, it is vital that all heat network projects are installed to high quality and safety standards. Polymer pipes offer a key advantage in this area, as they are naturally lighter than equivalent steel alternatives, so are easier to handle on site. Additionally, REHAU’s CLIP-FLEX shrouds and EVERLOC jointing system eliminate the need for hot works.
These shrouds are a key element of any district heating system, as they play a significant role in the network’s reliability and thermal performance. As part of the development of the CLIP-FLEX shroud, REHAU were keen not to overlook the importance of the insulating foam itself.
This polyurethane (PU) foam is inserted into the shroud during the installation process, providing the high-quality thermal insulation required. Traditionally, foam’s two components have been supplied in either foam bottles or foam bags of an equivalent size.
In the case of bottles, on-site mixing typically involves pouring one component into the other. Alternatively, a divider can be unsealed within a storing foam bag to mix these substances together. Both methods carry a risk of spills during handling, which can cause on-site complications.
The length of the chemical reaction involved when mixing the PU foam varies depending on the outside temperature, so added care is required during installation. Consequently, with the need for a larger rollout of district heating networks in mind, it is vital contractors look for solutions that enhance safety and practicality when insulating shrouds on polymer pipework.
Yes we can
It is with this in mind that REHAU has developed 2K-D foam cans, which have been designed to improve safety and handling on-site. As the two components are mixed inside the can rather than in the open air, the risk of any individual chemical components being spilled is eliminated. Crucially, these cans still use the same high-quality PU foam, with its excellent insulation properties.
These cans are also designed for ease-of-use, with activation triggered by rotating its base before shaking the can upside-down. The injection nozzle may then be inserted fully into the shroud, ensuring an even distribution of foam – another element that is harder to achieve with bottle or bag foam systems. Additionally, instead of using numerous different foam bottle or bag sizes for each shroud size as would usually be required on-site, REHAU’s solution has been designed with just one can size in mind, used in multiples as needed.
In conclusion, the UK district heating market faces significant challenges but holds immense potential for contributing to the Net Zero transition. With the introduction of the Future Homes Standard and increased housebuilding targets, the demand for efficient, low-carbon heating solutions will rise, and heating professionals need to adapt accordingly.
Innovations in polymer pre-insulated pipe technology, such as REHAU’s RAUVIPEX and 2K-D foam cans, offers practical benefits that enhance safety, efficiency, and reliability on district heating projects as demand increases. With the market continuing to evolve, informed material choices will be crucial in ensuring the success and sustainability of fourth-generation networks, paving the way for a greener future.
Learn more about REHAU’s district heating pipework technologies here.
For more on heat networks, visit elementalLONDON, the UK’s leading event for advancing the efficiency of buildings, on 19-20 November at Excel, London. To register for your free ticket, click here.
