Joints are vital to plumbing systems
Push vs Press fittings
Here we discuss each type of fittings features and benefits.
What are push fittings?
Push fittings operate by physically pushing a pipe into a fitting to provide a fast, secure and often reusable way to join pipes together.
How do push fittings work?
Push fittings are connected by hand and the process involves:
● Cutting the pipe to size using a pipe cutter to get a square edge
● Checking for and removing any burrs that could cause damage to the fitting[AA4.1]
● Inserting a pipe sleeve insert into the pipe to help give it rigidity and present a clean rounded end to make insertion into the fitting easier
● Pushing the pipe to the correct depth into the press fitting until it fully connects with the O- ring
Some push to fit plumbing fittings may have a grab ring on the outside of the pipe that can be used to lock off the pipe so that it does not rotate around the fitting. Each push to fit plumbing fitting has a collar around the pipe where it enters the fitting. When this collar is pressed back toward the body of the fitting it allows the pipe to be pulled out if required.
What are the benefits of push fittings?
The lack of specialist tools and speed of the fitting process makes push fittings attractive for the domestic and DIY markets where they offer a quick and simple way to carry out plumbing tasks.
What are the limitations of push fittings
Push-fit fittings can present issues. Problems may arise if pipe inserts are accidentally omitted, if pipe cuts are rough or uneven and damage the O-ring, or if the pipe is not inserted to the correct depth to fully engage the seal. This can lead to leaks and, in the worst case, complete joint failure resulting in significant flooding within a building, with associated costs for repairing and replacing water-damaged fittings and equipment.
What are press fittings?
Press fittings use a mechanical method to permanently crimp the fitting onto pipework.
When should I use push fittings vs. press fittings?
Push fittings are generally used when working on low pressure plumbing systems and due to their simplicity with no requirement to purchase specialist tooling are especially suited to the DIY market.
Press fittings are commonly utilised in large scale commercial and residential projects particularly in building services and the public health sector. In these applications the costs associated with water leaks can be particularly high, both in terms of damage to fittings and equipment and the resulting disruption to staff, residents and patients.
The 3 step process of installing a press fitting:
- Cutting the pipe to size using a pipe cutter to get a square edge and removal of any burrs
- Inserting the pipe into the press fitting
- Aligning the press jaws of the press tool and compressing the fitting to create a permanent leak-resistant joint
Are any specialist tools required to use press fittings?
Yes, press fittings use a special hydraulic press tool that can provide 1.9 tonnes of force to crimp a metal sleeve onto the pipe to form a secure and permanent seal.What are the benefits of press fittings?
- Press fittings form the seal on the internal bore of the pipes so that the press fitting creates its seal on a clean protected internal surface. This makes the fitting less susceptible to damage or contamination.
- The sealing method results in only a minimal increase in the external diameter of the pipe at the point of the press fitting.
- Press fittings with visual indicators confirm that the pipes have been inserted to the correct depth and there is no need to remember to add a pipe insert each time as these are not required.
- The press fitting process is quick and repeatable and delivers a secure, durable engineered join.
- Press fittings do not require any flame or hot works, making them suitable for use on sites without the need for fire permits typically associated with welding or soldering.
- They are also highly versatile, being suitable for plumbing, potable water, heating and gas applications, and are available in materials such as copper, brass, stainless steel and PPSU.
What are the limitations of press fittings?
● Unlike push to fit plumbing fittings the pipes connected by press fittings cannot be removed once attached.
● They are generally suitable for low and medium pressure applications rather than high pressure systems.
● The specialist tool used for press fittings requires calibration once a year
| Application | Recommended product |
|---|---|
| Press fittings in brass and plastic for Uponor’s | S-press and S-Press PLUS for Uponor’s range of pipes |
| Shrink fit for PEX | Uponor’s Q&E PE-Xa pipe |
| Modular fittings for 75-100mm MLCP | Uponor’s MLCP Riser systems |
| Electrofusion fittings and socket fittings | GF Aquasystem and Instaflex |
| Compression Swivel nut adapters for connections and transitions to other materials | Uponor Uni-C or Uponor S-Press Plus |
Summary: GF Piping Systems offers the perfect connection technology for every application:
- Press fittings in brass and plastic (S-Press and S_Press PLUS for Uponor's range of pipes)
- Shrink fit for PEX (Uponors Q&E PEXa pipe)
- Modular fittings for 75mm-110mm (Uponor’s MLCP Riser systems)
- Electrofusion fittings and Socket fusion for (GF Aquasystems and Instaflex)
- Compression Swivel nut adapters for connections and transitions to other materials (A)
| Push Fit | Press Fit | |
|---|---|---|
| Where is the seal formed? | External surface | Internal bore of pipe |
| Removable once sealed? | ✔ | ✘ |
| Specialist tool required | ✘ (although a pipe cutter is recommended) | ✔ |
| Visual indicator to check fitting has been installed correctly? | ✘ | ✔ |
| Does the seal significantly increase the external diameter of the pipe at the join? | Yes – up to 10mm around the joint | Minimal increase – 1 to 2mm |
| What type of pressure systems can the fitting be used with? | Low | Low to medium |