Mixed Material Plumbing

Today, let’s dive into a topic that’s super important but often overlooked - threads. And no, I’m not talking about the latest social media buzz; I mean the kind that keeps your pipes nice and leak-free.

So, here’s a question I hear all the time: Are copper fittings NPT, or National Pipe Thread?

Quick answer? Some are, but honestly, most aren’t.

Let’s unpack this, thread by thread.

What Is NPT Anyway?
NPT stands for National Pipe Tapered Thread. It’s basically a standard we use here in the U.S. for threaded fittings in plumbing, gas lines, and air systems.

These threads are tapered, which means they get tighter as you screw them together. They’re designed to create a mechanical seal, often using good ol’ pipe tape or some thread sealant. You’ll typically find them in steel, brass, and plastic fittings.

Just a few keywords to keep in mind: NPT fitting, NPT pipe, NPT threads, check valve, globe valve, plug valve.

But here’s the kicker...

Most Copper Fittings Are Not NPT
Copper fittings? Well,