Diffley-Wright Corporation
1891 Porter Lake Drive Suite 106
Sarasota, Florida 34240

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All about end connections

| written by twg

Valves are our thing here at Diffley-Wright, but what good are valves without end connections to go along with them? Today, we’re going to talk a little bit about some of the various End Connections out there on the market – what they are, what they do how they’re used.

Let’s jump right in!

ANSI Flanges

ANSI Flanges are connections that don’t have threads but instead have rims at the end that hook into another pipe or valve. They’re most well known for being very easy to remove from their lines. They come in a variety of difference rating classes and are capable of operating under a wide range of operating pressures and temperatures.


FNPT stands for ‘Female National Pipe Tapered’. They’re best used in steam applications because they are especially adept and not leaking. Generally speaking, their connection sizes are for applications 2” and smaller.


Buttweld chamfers are machined on the ends of the valve with the purpose of ‘butting’ up against match chamfers on the pipe in the system. As such, the chamfered ends on both pipe and valve form a V so they can accommodate welding. Buttwelds are almost always used with large valves or high-pressure applications. The one major drawback is that they’re not easy at all to remove from a line, which might add to a little added downtime.

RTJ Flanges

RTJ stands for ‘ring type joint’. These End Connections are a little more mechanical in nature than most- as they have a groove in the raised face that uses a soft metal ring that acts as a quasi gasket and seals off the entry. RTJ Flanges are particularly useful in high pressure applications.

Union Ends

Union Ends are great for quick installation and removal. They’re particularly well-suited for that function because there’s no pipe rotating required – it’s simply easy-on, easy off.

So there you have it – the basic differences and a quick rundown of what’s out there. If you have any questions or would like our team to help advise you on what technology might fit your company the best, simply give us a call!