Some four decades ago, we developed a low-cost flow stopping system called FOAMBAG™, based on the use of expanding resin foam. This effective yet simple technique works on all types of pipe material including cast iron, steel and PE. FOAMBAG™ is extremely versatile and can be used on vertical or tapering pipes, bends and non-standard diameters.

The major advantage of using FOAMBAG™ over conventional flow stopping bags is that far less pipe needs to be exposed resulting in considerably smaller excavations and reduced reinstatement costs. FOAMBAG™ has become an industry standard technique in the UK and has been used in many areas overseas including mainland Europe, the USA, Scandinavia and the Far East.

The technique works by inserting a semi-porous bag into the pipe to hold the foam in place as it expands. At full expansion, some of the foam seeps through the semi-porous material to adhere to the pipe wall.

Although developed for flow stopping natural gas pipes, FOAMBAG™ can also be used to seal pipes carrying other gases and fluids.

Nuclear Applications 

The FOAMBAG™ system is often used to seal off entry and exit points so that the entire void may be injected with expanding foam or in certain circumstances, a cement grout or epoxy resins.

The procedure has been adapted and successfully implemented to seal contaminated pipes, ducts and voids of varying sizes, shapes and orientations at a number of sites including Sellafield and Chapelcross.

SVI manufacture FOAMBAG™ kits suitable for sealing diameters from 5mm to 36” and these kits are available for purchase where appropriate. Alternatively we can design bespoke FOAMBAGS™ for individual projects, to seal larger diameters and non-standard shapes.

It is possible to position individual bags at strategic positions and inject foam or grout from a remote location (up to 75m away) with the use of CCTV cameras and injection equipment.

The National Nuclear Laboratory has carried out tests on the cured foam used in Steve Vick International’s FOAMBAG™ and associated systems and have rated it as having an 8-10 year lifespan in an area with a background radiation level of 7–9Sv.