Becoming more common in our industry these days, due to our occasional freak weather conditions, is the installation of anti-flood or non-return valves. These valves are generally fitted below ground on an outgoing pipe from a property usually within the last manhole chamber prior to the main sewer. The valve will shut under pressure should a main sewer surcharge and prevent flooding upstream through the connecting line. Unfortunately, even though London's (for example) sewer system was over engineered when constructed and although it has generally stood the test of time, the increase in the load required of it and misuse could not have been anticipated.
Anti-flood valves are by no means a new concept, original valves such as Eureka trunk valves or Tidal valves were used years ago and many still exist today, although you would struggle to find one that is fully operational. Eureka trunk valves are constructed out of cast iron and operate on a rising float to shut a flap, these suffer from corrosion and damage rendering them useless. A Forge anti-flood valve is a replica of these and has been on the market for some time, these are made of lightweight polypropylene and are more durable and reliable than the cast iron versions. Tidal valves are commonly made of vitrified clay and operate by a copper float rising to fit a rubber seating which closes the incoming pipe. These do not corrode to the same extent as cast iron but are never maintained and are usually also found non-operational. Both of these valves can be found fitted to lines entering a main sewer at a low invert level, proving even years ago main sewers not coping with a heavy load were still a concern.
Non-return valves can also be fitted to above ground pipework and branches preventing similar situations from occurring in communal stacks. They can basically be fitted anywhere, as long as there is easy access to them for servicing.
As well as the 2 mentioned above there are many other types of valve available, Kessel valves, Hunter valves, Capricorn or Redi valves and they all have advantages and disadvantages. Ranging from size, operational characteristics and required load. We can advise and recommend based on circumstances.
MG Drainage can assist you with anti-flood valve installations to; prevent backflow through drainage systems, sewer surcharging, back-up during heavy rain, property flooding, basement flooding, sewer flooding, back surge prevention, system isolation, flood defence and pump station failure. Prevention of flooding from rivers, brooks, culverts and streams.
We can install and maintain the following types of anti-flood valve / non-return valve; Hunter, Eureka Trunk, Multi-Kwik non-return, Tidal ball interceptor, Kessel, Forge, Redi, Aquaflow, Wavin, Fernco. ACO Junior M back flow gully, ACO ARA in-line automated anti-flood system, ACO SERA in-line passive anti-flood system.
There are many types of valve available, single flap, double flap, stainless steel flap, manual or automatic and the above is just a selection. Anti-flood valves should be chosen specifically to suit each case and requirement and we can advise based on circumstances.
Please call us on 01442 211967 to discuss your requirements.