A leaking drain which was causing waste water to enter the basement pool complex of a luxury Kensington town house was successfully sealed off by Dyno-Rod using the DRAINBLOCK BAG™ technique developed by Steve Vick International.
Dyno-Rod franchisee, Candid Services Ltd of Staines, Middlesex, were called in when the home owners found water on the floor around their underground swimming pool. A CCTV camera survey was carried out, using as access a manhole in the utility area. It was found that a drain from garden level descended to the pool level where it joined a pipe running from the basement to the exterior of the house, and ultimately to a local pumping station.
It was thought that waste was flowing back along this pipe which had previously been sealed off with a mechanical stopper but this had dislodged, allowing waste to flow out around the pool. It was decided that this redundant pipe had to be permanently sealed off, which is when Dyno-Rod contacted Steve Vick International, a company which specialises in developing flowstopping techniques for the gas and waste water industries.
With a Steve Vick International technician on hand to assist, Allan McRae of Candid Services inserted a DRAINBLOCK BAG™ into the redundant 4” salt glazed clay pipe, pushing it into position via the manhole in the utility area above, using a CCTV camera to monitor the operation.
The DRAINBLOCK BAG™ system uses a twin fabric bag and two-part expanding polyurethane foam. The resin and hardener are mixed together in a sealed sachet and zipped inside the porous retaining bag together with a piercing knife. This bag is then zipped inside an outer bag made of non-porous and semi-porous materials. The prepared DRAINBLOCK™ BAG is immediately pushed into place with the aid of drain rods attached to a tube on the bag.
As the foam begins to expand, the knife pierces the sachet allowing the foam to expand into the inner bag. As expansion continues, it seeps through this bag into the outer bag. At full expansion, the foam fills the outer bag and small quantities pass through the semi-porous panels to adhere to the walls of the pipe forming a permanent plug.
DRAINBLOCK™ BAG starts to act as a seal against water and odours in approximately 30 minutes depending on the ambient temperature. A full cure will be achieved in 12 hours. The major advantage of the DRAINBLOCK BAG™ is that it is inserted from an access point up to 15 metres away from the point which needs to be sealed.
In the Kensington home, once the DRAINBLOCK BAG™ had expanded and fully cured, the system was tested for leaks. The pipe on the other side of the drain was temporarily sealed off using an airbag and the drain and pipe was then filled with water and a dye was introduced. After testing the system in this way for 15 minutes with no leakage, the airbag was removed.
The whole operation took around two hours. Allan McRae says, “The job was a complete success and was carried out with ease. Using CCTV we were able to monitor the process throughout and see exactly how the DRAINBLOCK BAG™ expanded to seal off the pipe. We were able to assure the home owner that there would be no further waste leaking into his pool complex.”
Date published – 11th October 2011