Crimp, compression, expansion, and press sleeve…what do they all imply? There are several varieties of PEX fittings, and we frequently ask what they are and, more significantly, how they operate. Metallic or polymer insert fittings with a stainless steel clamp, or a crimp ring, push fitting, and cold-expansion fittings, are the most common types of PEX fittings.
Without getting too far into extremely technical details on the techniques used to manufacture these various varieties of PEX, here is a simple summary of the most prominent properties of each type of PEX pipe fitting, and why you should pick over another.
PEX fittings come in a variety of styles, each with benefits over other types of polymer plumbing tubing. PEX fittings create mechanical connections and are not solvent-glued in a similar way that CPVC, as well as other plastic pipes, are. There are multiple PEX tube suppliers, each with its own comprehensive range of fittings.
3rd party fittings are also accessible that may be used with just about any company’s PEX pipe, although observing the PEX manufacturer’s guidelines is critical. Use fittings that have been rated by a 3rd party testing and certification organization, such as IAPMO, NSF, IGL, CSA, or UL.
PEX fittings are often produced from one of three materials: brasses, plastics, or stainless steel. A push-fit fitting, on the other hand, employs a mix of these elements. As you can expect, each option has advantages and disadvantages, which we’ll discuss briefly shortly.
Crimp Fittings for PEX
PEX crimp fittings are the most often utilized kind of fitting in PEX systems. There is a wide range of fittings accessible for making PEX-to-PEX connections along with transitioning to other pipe material networks.
The majority of crimp fittings are constructed of brass (to ASTM F1807 specifications), however poly-alloy crimp fittings (also known as poly-plastic) are also accessible (produced according to ASTM F2159 guidelines).
Crimp fittings necessitate the use of copper or coated steel crimp rings as well as a PEX pinch or clamp tool. To form the closure with the tube, some manufacturers employ O-rings on various metal fittings (made to ASTM 2434 specifications).
Except for Reinforced thermoplastic, crimp fittings are congruent with all varieties of PEX tubes. Crimp fittings are suitable for many uses because they are inexpensive and widely accessible and very cost-friendly. A copper crimp ring or stainless steel pinch clamp is by far is among the most preferred and cost-effective alternatives in PEX B systems. A specialized tool is then used to secure the band or clamp to guarantee a perfect fit.
Compression Fittings for PEX
Compression fittings for PEX work similarly to compression fittings for other plastic or copper pipework. A compression screw, a compression band, and a compression insert make up the fittings.
Fitting the compression insert within the end of the PEX tube, slipping the tension ring over the pipework, and fastening it using the compression screw is how the connection is made. The compressed nut forces the ring and tube against the inserts as it compresses, producing an absolute sealing.
Compression fittings are popular among plumbers, contractors, and do-it-yourself homeowners because they are simple to install and dismantle. However, they are more costly than crimp fittings. Compression fittings are ideal when working with several contact points or when dismantling is expected.
PEX Push-Fit Fittings
Push-fit fittings (also known as push-to-connect fittings) are a comparatively new plumbing invention that is becoming increasingly popular for any type of pipework, including PEX. Joining PEX tubing using push-fit fittings does not necessitate the use of any crimp rings or special tools
Pushing the PEX pipe into the fitting, where it is grabbed and secured, is made possible by a sophisticated multicomponent locking system. The same technique allows you to dismantle the fitting, which is normally done with the help of a specific disconnecting tool.
Push-fit fittings are generally made of brass or DZR brass and work with all varieties of PEX tubing, as well as copper and CPVC pipes.
Expansion fittings are distinguished by an external plastic sleeve that goes over the PEX tube. The tube and sleeve are briefly stretched and extended to allow for the insertion of a fitting, which is firmly retained once the device is freed and the sleeve recovers to its previous size. This style of fitting takes considerable practice to master.
Press fittings are similar to crimp fittings, however, they do not necessitate an exterior crimp ring. Rather, after inserting the press-fitting sleeve into the PEX pipe, a pressing tool is often used to compress the tube until it latches to the fitted sleeve.
Press fittings are accessible for PEX plumbing. The mechanisms are unique and should be used in conjunction with the company’s press tool.
Is there a correct or incorrect PEX Fitting solution? No, in most circumstances. However, there are better and worse solutions based on your individual demands in your pipework and also depending on where you source them from.