The Ultimate Guide To Press Fitting

Despite its introduction to the market over 40 years ago, press-fit is still considered a relatively new method of joining pipework. As the saying goes, old habits die hard, and many plumbers and heating engineers still prefer to use traditional brazing methods. There is definitely a place for this way of working, however, adopting press-fit technology can have a number of benefits for installers says Richard Harvey, Commercial Director at Wolseley.


What is press fitting?

Unlike traditional brazing methods, press-fit involves no heat and no need to weld or solder joints and connections. It is this lack of skilled labour which seemingly puts experienced plumbing and heating professionals off — after all our industry is one that prides itself on engineering excellence and technical know-how. Rothenberger press fitting tool and accessories

Press fittings almost make the job easy enough for your average Joe to join two lengths of pipe and can make an installer’s training and hard-earned experience seem defunct. The technology, however, is an engineering feat in itself. The efficiency, safety and flexibility advantages it brings to plumbing and heating businesses make it difficult to ignore.

Press-fit works with virtually any pipe system and can be used in numerous applications ranging from the delivery and drainage of potable water, gas and even steam. The major press-fit manufacturers, such as Geberit and Pegler Yorkshire, supply carbon steel press fittings and stainless steel press fittings, as well as the standard copper press fittings.

Is press fitting safer than brazing?

Without the need for brazing torches, installers reduce the risk of causing a fire or sustaining burn injuries. This can be particularly useful in poorly ventilated areas of a building or when working in tight spaces such as cupboards, underneath floorboards or inside wall cavities. Some press-fit guns also include LED lights, making it easier to work in poorly-lit environments.

Press-fit removes the need to use consumables such as flux or propane, resulting in additional savings on replacing materials. The technology also reduces the amount of safety equipment needed to be worn on site and the amount of brazing by-product to clean after the job is complete. Naked flames are also banned on a number of sites, particularly in London, making press fit an ideal solution.

Some sockets such as the Geberit Mapress stainless steel are sealed with a plug that protects the them from dust and dirt on site, keeping the connection free from bacteria and contamination.

Is press fitting faster than brazing?

One of the drivers for growth of the press-fit market is the reduction in installation times compared to brazing. Some manufacturers of press-fit fittings claim installation times can even be reduced by up to two thirds. Press fitting works by inserting the pipe into the fitting which is then sealed by pressing the fitting socket and the pipe using the jaws of an electric press-fitting tool.

By reducing the time required brazing, installers can make room for additional work while providing the same level of quality and making the same amount of money on fixed price jobs. Unlike brazing, press system connections are quick to complete, with many connections able to be pressed in under 10 seconds. The method can even be completed on wet pipe systems, eliminating the need to shut off the system during the process.

When working on construction sites such as new build developments, in some circumstances, contractors may also be able to save the time of having to fill in paperwork relating to permits to work with open flames.

Do press fitted joints leak?

Simple answer: not if they’re done properly.

Many installers have preconceptions about the strength of the connection that press-fit systems can offer. With connections created with press-fit compression tools, attention must be paid to each manufacturer’s guidelines in order to create a secure, long-lasting, and leak proof joint.

The pipe must be prepared in accordance with these guidelines but providing the instructions are followed, press-fit provides a connection that is as strong as any. For added peace of mind, some suppliers’ fittings also have leak indicators in the form of specially designed O-rings. These fittings have a reduced section in two positions that allow water or air past the sealing element of unsuccessful connections and creating a visible leakage point.

While there is certainly an art to traditional brazed connections, many installers are turning to press-fit to complete jobs more quickly, safely and securely. Without the need to consider safety so heavily and the ability to fit and forget, this method should be considered by any plumbing and heating business looking to find time to fit in more work and decrease their overheads. The benefits of press-fit are becoming increasingly difficult to ignore.

Step by step guide to perfect press fittings

Cut the pipe

Use a pipe cutter with a new or undamaged wheel. It is important to ensure that the pipe is cut completely square. Tube ends should be clean and free from scratches or damage on the end that fits inside the fitting.

Remove burrs

Make sure that the internal and external tube ends are free from burrs or sharp edges by using a deburring tool. Then wipe the tube end clean to avoid damaging the O-ring when the tube is inserted into the fitting.

Ensure the O-ring is seated and lubricated

Before inserting the copper tube, ensure that the O-ring is seated correctly, free from damage and lubricated. If not lubricated, a small amount of water can be used.

Mark insertion depth

In order to make the perfect joint, the tube must be correctly inserted into the fitting until it reaches the tube stop. Marking the insertion depth on the tube will ensure that any movement is detected, which is important if the joints are to be pressed at a later time.

The pressing operation should only be undertaken when the tube has reached the tube stop and the previously marked tube realigns with the fitting.

Complete the joint with the pressing tool

Ensure that the correct size jaw for the fitting is inserted and locked into the pressing tool. The jaws must be placed squarely on the fitting. Depress the trigger to begin the compression cycle of the tool.

The cycle is complete when the mouth of the fitting is fully enclosed by the jaws, and the internal piston returns to the start position. Now release the jaws from the fitting. The joint is now complete.

Press fitting FAQ

90 degree copper press fit pipe fitting

What grades of copper tube do press fittings suit?

You can use press fitting with the Annealed (R290), half hard (R250) and soft (R220) grades of copper tube. The tube dimensions must comply with EN 1057.

Can you rotate a press fitting once installed?

No. Once pressed, they cannot be rotated.

Can press joints be dismantled and reused?

No, press fitting is a permanent installation.

When using older pipes, how do you prepare the surface for press fitting?

The surface should be prepared in the same way as with new pipe. As long as there is no corrosion, the tube dimensions comply with EN 1057 and the fittings are installed correctly, there will be no leaks.

What are the limitations of press fitting?

It cannot be used where pressures are greater than those recommended or where corrosive fluids/gases need to be transmitted.

With press-fit joints, what pressure do you need to test to and for how long to show any leaks?

Unpressed fittings are identified by pressurising the system with a pressure range of 1 bar to 5 bar for water and 22 mbar to 3 bar for gas. Final testing of the system should be conducted in accordance with the Water Regulations Guide and/or the Building Regulations.

Can press fitting be used with medical gas?

No, it’s not recommended for use with medical gas.

Does the clipping of press fittings differ from a welded copper application?

No, the same type of clips can be used.

Can press fittings be used on compressed air or oil lines?

Water fittings are recommended for compressed air (oil free). Press gas fittings are suitable for all compressed air applications.

Can press fittings be installed on pipes where the mains line won’t shut off?

Yes, press fitting can be used in wet conditions and after pressing they’ll provide a watertight joint.

Can press fittings be used on chrome tube?

Yes, provided that the tube complies with EN 1057. However, it is recommended to test a piece first as some splitting of the chrome may occur.