Every job an installer undertakes is likely to be different in some way and we can often be pushed for time, especially if things haven’t gone to plan or as smoothly as we’d hoped. However, even when the pressure is on, it’s critical that we don’t forget the importance of testing.
Testing is exactly what led to the discovery of the issue experienced by Bruce Rothery that we discussed in our last column. Bruce found that the way in which the pipework had been installed was causing two different types of dry-trap tundish to fail in exactly the same way.
This is just one of the reasons we encourage installers to test and verify the correct operation of our dry-trap tundish at the point of installation. We also detail the correct procedure in our comprehensive Manufacturing Instructions to assist installers, something which isn’t provided with other similar products on the market.
The rationale for testing our products in every situation is to verify that the downstream system can cope safely with the flows expected from the safety relief valve. We advise on undertaking a trickle test using a small amount of water to ensure the valve opens – this is called the trigger point – as well as testing the full volume flow.
Testing to establish full flow is particularly critical to ensure that both the tundish and downstream pipework are able to cope safely and ensure that the product is able to perform as intended.
It’s vital that the valve is manually operated in a similar way to how it would normally operate in a failure scenario. Pressure Relief Valves are designed to open slowly so during testing it must be opened gradually until a small flow is established, then slowly opened further until full flow is established. Keeping the valve open for about 10- 20 seconds will show whether both the tundish and downstream pipework can handle full flow.
Testing enables us to guide the installer through a troubleshooting process should it reveal any issues. For example, in the trickle test the valve should open with between 5ml and 30ml of water. If the valve fails to open and overfills, we advise disconnecting the D2 pipework and testing again. If it then operates as intended, this suggests an issue with the D2/drain pipework running at a slightly positive pressure.
When testing full flow, if the tundish immediately overfills there may be an issue with the volume flow rate being greater than the rated capacity of the tundish. If water discharges at full volume for a few seconds and then overfills, this indicates that there could be a problem with the D2 waste pipe not allowing the water to flow freely enough.
We know that these issues aren’t unique to only our product but by encouraging installers to test their applications and taking the time to provide clear Manufacturing Instructions, we believe we can help them to easily overcome any issues they will face.