Inch (also termed Imperial) pipe sizes ARE
NOT size compatible with metric pipe systems, plumbing or
waste pipe sizes.
The inch size refers to an "approximate bore" of the
pipe (it's an old system that has
been adopted from one which originated with steel pipe in the 1800's!), not the actual measurement of either
in internal or external diameter of the pipe or fitting. For tables giving details on the exact sizes see
our technical document.
Plain Fittings - All our PVC pipe fittings are fully compatible with all other
industrial PVC pipework. This is with the possible exception of union fittings, as some manufacturers use their
own thread design for the union nut connector.
Threaded Fittings - All our fittings, like most PVC manufacturers, have BSP tapered threads; please note that
these ARE NOT compatible with North American NPT threads. Please note however that our tank connectors/ bulkheads do not as they require a backnut to
thread evenly along the full length. Male tapered threads are compatible with femal parallel and tapered threads. Female tapered threads are not compatible
with male parallel threads. Please contact us for advice if you require to attach a male parallel thread into a female thread.
Ball Valves - Ball valves are not generally cross compatible from the point of
view of taking the body out of one make, and replacing it with another make. Often the union threads are
different and the body of the valve may also differ in length. If you need to replace a ball valve, our advice
would be, if there is space, to cut the pipe and install a whole new valve.
Unless otherwise stated (variations can apply to some PVC fittings of 8 inches and
over), all fittings and valves have a minimum continuous pressure rating of 10 bar (147psi)
Our inch PVC fittings are all manufactured to ASTM and BS standards.