According to research carried out by the Home Builders Federation, sustainability is now a key driver in people’s home buying choices.

The survey reveals that 73% of respondents are worried about the energy performance of their current home, and 24% say that energy efficiency will be “crucial” to their next home move.

This survey is released in the build-up to the long-awaited amendments to Part L of the Building Regulations which will come into force in June, and increases the pressure on traditional heating sources already under scrutiny.

To meet the building regulation standards, new properties will need heating systems that have a flow temperature of 55°C or below, suggesting low temperature heat sources, heating systems, and heat networks will become integral to the government’s plans to achieve reductions in carbon emissions.

The increase in heat network projects will mean more contractors will have to become familiar with the technology.

If you are looking for advice for a district heating project, talk to a trusted manufacturer who should be able to advise you on the ideal products for the job, and also the key points that need to be considered during installation.

Polypipe, for example, can advise on which pre-insulated pipes are needed for each part of a project, as well as any testing that needs to be done.

Available options

Single, double, and quadruple insulated pipes come in a wide range of sizes and are made specifically for district heating.

The single medium heating pipe is primarily intended for the transport of heating water in buried distribution networks. 

Whereas the double pipes, which combine both the flow and the return medium pipes in the same jacket pipe, are primarily intended for the transport of heating water in buried distribution networks. 

Additionally, both heating and sanitary pipes are available in a combined jacket pipe known as a quadruple pipe.

There are cross-linked polyethylene PE-Xa pipes, which are flexible, and heating pipes are colour coded to enable easy identification of flow and return during installation; some even come equipped with mounted dust or shrink end caps.

The multilayer thermal insulation is typically made from cross-linked, microcellular polyethylene PE-X foam with a water-repellent closed cell structure, characterised by its durable, non-ageing insulation performance, and its permanent elasticity, maximising and maintaining the thickness of the insulation layer, even after bending multiple times.

And high grade, UV-resistant, double-walled, corrugated HDPE jacket pipe shields the pre-insulated piping system against mechanical impacts and moisture, while maintaining maximum flexibility.

Laying pipework

A pre-insulated pipe can be laid into a trench directly from the coil but, to avoid damaging its outer HDPE jacket, always remove all sharp objects from the ground, and lay the pipe in a sand bed.

When laying pipes of larger dimensions and lengths, pulling devices such as winches or tail-end rollers may be used. Always connect these devices to the medium pipe.

Roll the pipe alongside or straight into the trench, ensuring that you keep the stated bending radius. For double pipes, the flow and return must be laid on top of each other. 

We recommend that you install identification markers on the pipe network and all branches, and you must conduct a pressure test and fill in a report before backfilling. 

Partially fill the trench with a first layer and backfill only after fully covering the pipes with sand, all the while respecting the minimum layer dimensions indicated in the trench dimension drawing. The filling material must be compacted layer per layer until it is 500mm deep, at which point the coverage may be compacted by machine.

All pipe systems intended for potable (drinking) water and other sanitary domestic tasks, such as washing and showering applications, should always be thoroughly rinsed before they are commissioned, in accordance to WRAS requirements. 

The installation of adequately anchored fix points at the system’s extremities (typically at wall penetrations) is mandatory. This is to secure the connected plumbing against the potential impact of the systems dilatation forces (thermal expansion/retraction).