english – Question of the day: How durable are ‘inliner processes’?
Does it necessarily have to be a new pipe if the old one can be renovated from the inside? Above all, the useful life plays a role in this question.
The following case conforms to the enquiry to the RSV: The drain in a mid-terraced house is getting on in years. New construction or sewer renovation? It makes sense for all owners to decide this question together, as the pipe that leads into the public collector sewer is shared. Some parties favour renewal - the owners who asked us are in favour of sewer renovation. After all, there is a difference of more than 18,000 euros in costs between the two solutions. As an expert has confirmed that the pipe is suitable for renovation, the question now was how economical and durable a renovation using the inliner method - the technical term is ‘cured-in-place pipe lining’ - can be.
Our statement on this:
The curing on site pipe liner systems (also known as the ‘inliner process’) are established construction products in the field of sewer rehabilitation and are used worldwide for public collection pipes to secure the wastewater infrastructure. Municipalities in which the local network operator is also responsible for the sewer renovation of connecting pipes in private drain systems use this procedure as standard.
Information on the application in the area of private property drainage pipes can be found on this page https://rsv-ev.de/hausanschluss (only in German) .
The technology is regulated in the international standard EN ISO 11296-4 and defined in numerous national standards with regard to its additional requirements, for example in DWA-A 143-3 and DWA-M 144-3. In addition, the pipe liner systems have general national technical approval from the German Institute for Building Technology (DIBt), which includes extensive suitability tests and internal and external monitoring. On behalf of the federal states, the DIBt is responsible for providing official proof of the safety of construction products. Further information can be found at https://rsv-ev.de/dibt-zulassungen.
In principle, a technical useful life of at least 50 years is assumed for hose lining technology. EN ISO 11296-4 requires the determination of a long-term creep factor in the 10,000 h test, which allows extrapolation to a 50-year service life. The suitability tests of the systems with regard to high-pressure flushing resistance and abrasion resistance also simulate 50 years of pipework operation. The results of the long-term tests form the basis for the static calculation of the cured-in-place pipes and thus ensure the minimum requirements for achieving a useful life of at least 50 years.
A liner laminate manufactured in accordance with the system specifications of a tested and approved cured-in-place pipes refurbishment system has a calculated useful life of at least 50 years.
The fact that cured-in-place pipe lining is a renovation process and not a renewal process initially has nothing to do with the question of longevity. It is a technical categorisation according to DIN EN 15885:2019-10. It is now common practice for local authorities to include the costs of sewer renovation in the investment budget and not to finance them via the current fees budget, as these are investments that will benefit future generations.
Further information can be found in factsheet 1.1 Hose lining https://rsv-ev.de/merkblaetter-detailansicht/merkblatt-schlauchlining