will NPT fitting work with IPS fitting?

**rick.a** · 04-13-2011, 02:20 PM

Are these 2 standards the same? Or do they have different taper, or thread count or pitch? I tried to look this up but got more confused than ever. I now know what they stand for, but will they fit together properly and not leak. Using 3/4" brass fittings.
thanks,

hj · 04-13-2011, 05:38 PM

You have to define whether "IPS" means "iron pipe size" or "iron pipe straight" thread

**jimbo** · 04-13-2011, 05:41 PM

In most contexts, we are talking about the same thing. NPT refers to National Standard Pipe Thread Tapered. IPS is not a stricly technical term, or at least it doesn't refer to threads. It stands for IRON PIPE SIZE, so really refers to pipe ID and OD. In most contexts, we use IPS in referring to NPT ( tapered) threads, although there are plenty of applications in daily use where the threads are NPS ( National Standard Pipe Thread Straight).

Now you know why plumbers mumble to themselves in their sleep!

**BenWara** · 04-13-2011, 08:07 PM

Originally Posted by jimbo

In most contexts, we are talking about the same thing. NPT refers to National Standard Pipe Thread Tapered. IPS is not a stricly technical term, or at least it doesn't refer to threads. It stands for IRON PIPE SIZE, so really refers to pipe ID and OD. In most contexts, we use IPS in referring to NPT ( tapered) threads, although there are plenty of applications in daily use where the threads are NPS ( National Standard Pipe Thread Straight).

Now you know why plumbers mumble to themselves in their sleep!

per the 27th edition of the Machinery's Handbook, NPT refers to American National Standard Taper Pipe Thread.