FAQ - WaStop® Inline Check Valve

Common questions and answers

Can WaStop in used in sand applications? 

Yes, WaStop functions well in sand. If the pipe gets completely filled with sand we recommend a solution with multiple smaller WaStops to release the flow on a more frequent basis ensuring that sand is removed from in front of the valve. The pulsating flow also ensures the sand is kept away from the valve.


What sizes are available?

DN80-1800mmNPS 3-72


How long does WaStop last?

Approx 20 years depending on the installation site.


What is the lead time?

We have sizes DN75-1000 in stock ready for immediate dispatch and over DN1000 or special items approx 4-6 weeks.


Does WaStop work in salt water?

Yes, WaStop has been tested since 2002 in salt water applications. The material used in WaStop is resistant to the drying effects of salt water, and being UV stable is perfectly suited to tidal applications.


Can WaStop be used in sewer applications?

Yes, WaStop is often used in sewer applications to stop backflow, and also odour spreading.


How long has WaStop been sold?

WaStop has been sold in 56 countries since the year 2000. We have sold over 55 000 valves in a variety of applications. Many of these can be found in our case studies.


What materials are available?

WaStop is available in stainless 304 och 316. We recommend 316 for salt water applications or where there is higher levels of H2S.


What backpressure can WaStop withstand?

We have three membrane durometers available. The standard membrane withstands 5m (16') of back pressure, the soft 3m (12') and the hard membrane 8m (26') of back pressure.


Does WaStop have a low 'cracking pressure'?

WaStop has a unique pulsating flow which eliminates the problems associated with cracking pressure. The term 'cracking pressure' relates to the point at which the valve starts to release a little water. Flap valves and duckbills in particular exhibit a cracking pressure which is the point at which they start letting a little water out. The problem with this is that releasing a little water means debris upstream cannot pass through the valve. WaStop has a pulsating flow, which means that we have a pre-determined opening pressure and closing pressure. When the upstream pressure reaches the opening pressure level, the valve will open releasing the upstream flow including the debris. When the upstream level reduces to the closing pressure point the WaStop will snap shut and close firmly.


Can WaStop be used for air/odour applications?

Yes. WaStop seals tightly can effectively stops air flow and therefore odours spreading through pipe networks.


Can WaStop be installed in existing infrastructure?

WaStop is frequently installed in existing infrastructure and often where other forms of backflow protection have failed. WaStop inserts inside the existing pipe and bolts on to the headwall or the pipe itself. No other civil works are required.


My chamber/vault is small, can WaStop be adapted?

WaStop can be adapted to different installation scenarios. WaStop can be supplied with a 1/3 shorter body to fit into small chambers or vaults. Please contact Wapro for more information


What happens if the recommended max backflow is exceeded?

WaStop is built with a safety factor of 1.2. If the pressure exceeds this point the membrane material in WaStop will be stretched to the point of fatigue. 


My pipe is VCP - will WaStop fit?

Yes. WaStop is designed to fit into any pipe type. With a tapered gasket and unique design WaStop can used in a wide variety of pipes such as RCP, PVC, PE, HDPE, VCP, corregated metal pipe, cast iron pipe etc all with different pipe ID's.  If your pipe has been lined or is particularly special please contact Wapro for advice. 


Can Wapro provide elliptical outlets?

Yes. Wastop is provided with an elliptical flange mount that can be attached to the inside pipe diameter or flush mounted.


Since the valves are made in Sweden what is the average delivery time?

Wapro utilzes warehouse availabilty of the most popular sizes from 4" to 36" and can usually deliver in 5 to 7 days. Custom end fittings and short body valves will require 30 to 45 days to ship. 


Is it possible to decrease the OD of the inlet-side of WaStop and for the valve to still be suitable for 5MwC back pressure? 

Yes, we can produce a bespoke WaStop with one collar to decrease the OD of the inlet-side and for the valve to still be suitable for 5MwC back pressure. 

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