How to select the right type of ball valve for a pvc pipe system

Selecting the right ball valve for a plastic pipe system can be critical. In this video, we explain how to decide whether a single or double union ball valve should be used.

In most applications, a double union ball valve is the most appropriate valve to use. The advantage of a double union ball valve is the valve body can be completely separated from the pipeline, even if the pipeline is fixed either side. This allows for the valve to be inspected for blockages, seals to be checked, cleaned and replaced and then put back into service very rapidly. To perform the same with a single union ball valve, would require the pipe to be cut, as only one side of the valve can be removed using the union nut.To refit the valve a  socket  will have to be glued inline. This will mean that the system needs to be down for many hours, whilst the cement dries.

Single union ball valves are only really of use at the end of a pipeline, where there is nothing attached or permanently fixed, to the other end. Such situations  include  the ends of scour lines and drain lines or entry into an open tank or other vessel.

Ball valves are the lowest cost of any type of valve used in plastic pipe systems. They are very good where you need either a fully open of fully closed valve. When fully open they run at full bore, with very little headloss or restriction, making them very energy efficient. The nature of the ball however, combined with only a 90 degree turn of the handle between fully closed and fully open, makes flow control, using a partially open valve, very difficult to accurately set. Applications where a control of the flow rate is required is best served by either our fine control gate valves or diaphragm valves.