Do All Fittings Have to Go Inside the Pipe?

When it comes to plumbing and pipe installations, there is often some confusion about where fittings should be placed. Do all fittings have to go inside the pipe, or can they be installed on the outside? The answer, as with many things in plumbing, is not a simple yes or no and depends largely on the specific application and type of fitting.

Compression Fittings

One of the most common types of fittings does indeed feature an external design. Compression fittings (also known as compression couplings) have a distinctive feature: they have a collar, nut, and washer that are placed outside the pipe.

By tightening the nut, you compress the seal, making the connection tight and secure. These fittings are particularly popular in applications that require regular maintenance or reconfiguring because of their ease of assembly and disassembly. They are commonly used in water supply lines, gas lines, and air conditioning systems.

Plumbing Applications

When discussing plumbing specifically, many fittings also reside outside the pipe. For example, garden hoses and PEX (cross-linked polyethylene) crimp-on fittings typically go inside the pipe they connect. However, other fittings like copper,iron, compression flare, and flange fittings, as well as PVC (polyvinyl chloride) and sharkbite fittings, go outside. These fittings are designed for durability and are often used for outdoor applications where weather resistance is crucial.

The Importance of Installation Location

The location of fittings is critical for ensuring the proper function and longevity of your plumbing system. Proper installation increases safety and efficiency while reducing the risk of leaks and other issues. While these fittings differ in design and application, they share the common goal of providing a secure and leak-free connection.

Fitting Placement and Considerations

So, why do some fittings go inside the pipe, and others outside? This choice is often based on the material, compatibility, and intended use of the fitting. Inside fittings offer easy access for maintenance and are ideal for applications where visibility and accessibility are important. External fittings, on the other hand, are great for outdoor installations, such as yard irrigation systems, where they can be better protected from the elements.

Conclusion

In summary, the placement of fittings inside or outside the pipe depends on specific application needs. Compression fittings, commonly used in various piping systems, always feature an external design. For plumbing applications, most fittings are placed outside the pipe unless the application specifically requires an internal placement. Understanding the proper fitting location is essential for maintaining a safe and efficient plumbing system.