DrainsAid were contracted by a Council to undertake a drainage rehabilitation scheme using a variety of techniques including Excavation, CIPP Lining and M-Coating Manhole Rehabilitation.

The manhole requiring rehabilitation was 4m deep with 1800mm diameter concrete rings and was suffering from infiltration which increased during adverse weather and heightened ground water levels. We were tasked with sealing the manhole in order to stop the infiltration and therefore bring the manhole up to adoptable Yorkshire Water standards.

Manhole access was reasonably good although it was located on the road of a cul-de-sac so we have to ensure our TM was correctly laid out and the site footprint was kept as small as possible to allow ingress and egress from the street and not disrupt the residents. It was our intention to complete the works in one day on site, again keeping disruption to a minimum.

In order to seal this manhole DrainAid decided to employ the innovative Hermes M-Coating technique. This rehabilitation procedure is ideal for round and rectangular manholes with widths between 500 mm – 3,000 mm and depths up to 25 m. The technology uses a centrifugal spray and winch to coat the walls of the manhole with up to 100 mm of ERGELIT mortar. The centrifugal spray runs at 5000 rotations per minute and operates until the predetermined coating thickness is reached. The Ergelit mortar is specifically designed to halt infiltration.

When compared to traditional repair methods this process is a much more efficient and cost effective solution and would also have less impact on the environment, it also drastically reduces the need for man entry.

Firstly, the manholes were cleaned using dual rotating high pressure water jets on an automated winch, which leaves a clean, firm surface for the KS1 Ergelit mortar to bind to.

The next stage is to apply the mortar using the centrifugal application spray head. This spray head operates under a computerised control system. The operator will input the manhole dimensions and thickness of coating required (10mm in this case) into the system to allow it to calculate the number of automated passes that are required to achieve the specified finish.

The built in mixer produces the necessary mortar consistency and pumps this to the centrifugal spray head on the automatic winch. Throughout the operation, the control system produces continuous readings including the remaining time and mortar required.

Once the mortar is applied it begins to set immediately and the manhole can be back in use within 1 hour of curing. The result is a manhole which is fully sealed, resistant to water infiltration and H2S corrosion.

If you require any of our lining or manhole rehabilitation services, ring us now on 08000180123 or use our online contact form