Articles & Case Studies

Highways Agency approve Flexseal products for surface water run off

Posted: Tuesday 12th May 2009

After a successful trial as part of the M1 motorway widening project, the use of Flexseal Lateral Connections has been officially approved by the Highways Agency.

Two lateral connections have been approved; the UA saddle and the PA saddle. As part of the Highway Agency’s approval process, twenty of them were used between J25 and J26 of the M1. They were installed to attach lateral pipes into the 600mm twin wall ribbed surface water drainage pipe, and each was installed in around 7 minutes from pipe exposure. The increase in impermeable surface area after the widening will lead to vastly increased volumes of surface waste water, largely contaminated with oils and hydrocarbons.

The use of Flexseal Lateral Connections was preferred to using an expensive factory welded junction which could be easily damaged when re-excavating, or cutting an entire section out of the pipe and using a standard junction as a joint.

Another key factor was the WRc Approval of these saddles, achieved through an intensive programme proving the integrity of the seals; between the main pipe and the saddle, and the saddle with the lateral pipe.

After these initial successes, the Birmingham-based contractor will now be installing over 100 UA and PA saddles between J25 to J28 into pipes ranging from 450mm to 3000mm diameter.

Twelve of Flexseal’s market leading large diameter couplings have also been used, in conjunction with twenty-eight Flexseal bushes – these are used when connecting pipes of significantly different outside diameters. There is also likely to be several Flexseal FA150B saddles used on the concrete pipes at the site.

The design of the drainage has been to Highways Agency Design Standards.

Carriageway run-off is collected by surface water channels before discharging in to a sealed piped system. In agreement with the Environment Agency the pipe networks have been designed so there will be no increase in the existing discharge rate at outfalls into water courses. This has been managed by providing retention in the pipe networks to temporally store the additional surface water run-off generated by the widening as well as an additional 20% rainfall intensity as an allowance for future climate change.

Pollution and spillage control measures are being provided prior to discharge to outfalls.

Search online for “Flexseal Lateral Connections” for details on the full range, or call 01226 340 888 to hear more.

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