IPS, the way that faucet, and in most cases, uses it means Iron Pipe SIZE. I do not think I have ever seen it refer to “iron pipe straight”. Even when the thread is “straight” such as faucet shanks, they still refer to it as iron pipe size.Click to see full answer. Also to know is, what is an IPS fitting?According to the Googles, IPS is Iron Pipe Straight thread. It’s meant to seal on a washer-shaped gasket (like the threads the hose for your toilet or faucets attach to). Which is weird, because I’d think those arms would be designed to thread into a brass NPTF fitting in the wall/ceiling.Additionally, what is IP thread size? The United National Fine thread standard for quarter-inch bolts and nuts is 28 threads per inch. The standard thread for 1/8 IP pipe, however, is 27 threads per inch. Additionally, what does IPS in plumbing stand for? Iron Pipe Size (IPS) refers to an old pipe sizing system still in use by some industries, including major PVC pipe manufacturers, as well as some legacy drawings and equipment. The iron pipe size standard came into being early in the 19th century and remained in effect until after World War II.Are NPT and IPS the same thread size?According to the Googles, IPS is Iron Pipe Straight thread. NPT is a tapered thread, designed to seal on the threads, which is why you put pipe tape on them – to lubricate them and help the threads deform and create a seal. So, while having no personal experience, I would say no, they will not thread together.