Solving the Mystery of Plumbing Abbreviations

what does FIP mean FCM mean FGH mean

Know the code to buy with confidence

FIP? MIP? FGH? MGH? FCM? One of the hardest things for consumers to grasp is what all those puzzling plumbing acronyms mean. Are they important? You bet. They accurately indicate the particular kind of ends on every hose or adapter.

That’s why we’ve put together an easy-to-understand overview with photos of the key plumbing abbreviations you’ll find mentioned on Certified Appliance Accessories hoses and connectors.

What does FIP mean in plumbing? MIP?

FIP means Female Iron Pipe. MIP is Male Iron Pipe. As the Pure Water Gazette points out, sometimes FIP is called FPT or Female Pipe Thread. And MIP is called MPT or Male Pipe Thread. To make matters worse, sometimes they are referred to as NPT or National Pipe Thread. And they aren’t necessarily made of iron—they could be made from copper or steel.

Here at Certified we use the more common FIP and MIP terms. FIPs have threads on the inside, MIPs on the outside. These connections usually require plumber’s tape around the male threads to ensure a tight seal.

Common usage is to connect a gas line to a gas dryer, range, water heater, or furnace—systems that are pressurized or carry hazardous materials like natural gas. You can also find a brass compression to MIP elbow on the end of water hoses used in dishwasher kits. Adapters are included in those kinds of kits case another kind of fitting is required. FIPs do come in various sizes, so one size does not fit all.

The top image is a MIP. The bottom image is a FIP.

FIP endFIP

What does FGH mean in plumbing? MGH?

FGH means Female Garden Hose. MGH means Male Garden Hose. If you use an outdoor watering hose, you are quite familiar with these ends, even if you’re not familiar with their technical names.

You’ll find FGH connectors on washing machine water hoses, steam dryer water hoses, dishwasher water hoses, and Y connectors. The FGH end does require a washer.

The top photo is FGH. The bottom photo is MGH.

FGH

MGH

What does FCM mean in plumbing?

The CM stands for Compression. So FCM is Female Compression. Often these ends are referred to simply as compression rather than FCM. They can be a bit trickier to identify as they are not so obvious.

So how do they get their name? And how do compression fittings work? They get their name because the join is made by compressing tubes or pipes together—often with a wrench. The wrench tightens the outer nut which then squeezes an inner ring.

We like the explanation given by The Natural Handyman

“A compression fitting is a type of coupling used to connect two pipes or a pipe to a fixture or valve. It consists of three parts...the compression nut, the compression ring, and the compression seat. The nut is slid onto the pipe, followed by the compression ring. The pipe is slid into the fitting and the nut is tightened down. As the nut is tightened, the compression ring is pressed into the seat, causing it to compress against the pipe and the compression nut, providing a watertight connection.”

Compression fittings are also used to connect pipes of different materials, like PVC and copper. They also eliminate soldering and leave the original ends intact for future disassembly.

You’ll see these used in hooking up water lines in tight spaces and connections that are used a lot—like the ice maker water line, dishwasher water line, and even under the toilet and sink. One hazard during installation is overtightening the nut. If it’s too tight, it deforms the interior and can cause leaking. No plumber’s tape or pipe dope is required but some experts recommend a little light oil on the threads of larger fittings to make tightening easier.

Petra dishwasher hoses come with a brass MIP elbow already attached to one of the FCM ends. The elbow is designed to simply screw on/off from the compression end—no wrench is required.

The top photo is FCM. The bottom photo shows the MIP adapter placed on an FCM end.

FCM

MIP end

Mystery solved

It’s unfortunate that plumbing connectors are not universally the same across the board. So, it’s important that you understand those puzzling plumbing abbreviations. The acronyms identify the kind of fitting end, provide clues as to the application, and let you know what you can expect when it comes to installation.

Know the code to buy right!