Lifetime and performance of the PE-RT service pipe Lifetime on a plastic service pipe can, according to EN15632-2 Annex A and prEN17878-2 Annex A, be calculated according to Miner’s rule when knowing the typical temperature and pressure profile of the pipe system. The service pipe in PertFlextra is SDR 7,4 PE-RT, whereas the service pipe on PEX pipes on the market is SDR 11. SDR 7,4 will have a higher wall thickness than SDR 11, and when doing the calculations according to Miner’s rule, PE-RT SDR 7,4 will have better lifetime performance compared to PEX SDR 11. In other words, a system with PE-RT SDR 7,4 can be operated with higher pressure than a system with PEX SDR 11 at the same temperature profile. Low heat loss during the entire lifetime of the system There are three contributors to the low heat loss over a life- time.
Secure low heat loss in the entire lifetime of the pipe system
Develop a system with plastic service pipe with the possibil- ity of having an integrated surveillance system.
The plastic service pipe shall be weldable, leading to the possibility of using electro-fusion couplings when connect- ing the service pipe.
The flexible pipe shall be easy to install with a focus on the work environment.
During this project, LOGSTOR developed PertFlextra, and 1900 m TwinPipe was installed in a project in Høje Taastrup, and 1900 m single- and TwinPipe was installed in Lund.
For further information about the COOL DH project, please see https://www.cooldh.eu/this-is-cool-dh/
PertFlextra in details PertFlextra is a complete range of diffusion-tight, flexible, pre-insulated pipe systems for community heating and district heating, according to prEN17878-1/2. The service pipe in PertFlextra is made of polyethylene PE-RT type II SDR 7,4 featuring an aluminum diffusion barrier that prevents the diffusion of oxygen into the media and water vapor from the water into the PUR foam, thereby ensuring that the foam stays dry over a lifetime and heat loss remains low. The service pipe is insulated with PUR foam, and the outer casing of HDPE has a built-in EVOH diffusion barrier that will ensure that heat loss property will not deteriorate over the life- time.
Low lambda value of the PUR foam
Diffusion barrier for water vapor on the PE-RT service pipe
Diffusion barrier in the corrugated casing for the PUR foam insulation gasses
Low lambda value of the PUR foam: The PUR foam where cyclopentane is the blowing agent.
Cyclopentane is accepted in the REACH regulations and does not conflict with any future additional restrictions, e.g., related to PFAS restrictions. Cyclopentane leads to insulating proper- ties that are far better than, for example, pure CO2-blown PUR foam.
The following describes the outcome of the targets defined in the COOLDH project.
The latest lambda test on FlextraPipe has been carried out at
PertFlextra
Corrugated outer casing and high density polyethylene (HDPE) with built in diffusion barrier (EVOH)
Polyurethane (PUR) with blowing agent Cyclo pentane
PE-RT protection layer
Aluminium diffusion barrier
PE-RT type II SDR 7,4
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