When building or maintaining a pneumatic system, one of the most common decisions is whether to use push-in (push-to-connect) fittings or compression fittings. Both are reliable when correctly matched to the application — but they suit very different circumstances. This guide cuts through the differences to help you choose confidently.
How Push-In Fittings Work
Push-in fittings grip the tube using a stainless steel collet inside the fitting body. When you push the tube in, the collet teeth bite into the outer surface and hold it securely under pressure. The harder the pressure tries to pull the tube out, the tighter the collet grips.
Releasing the tube is equally simple: press the release collar inward, which retracts the collet teeth, and pull the tube free. The entire process takes seconds and requires no tools.
Push-in fittings rely on the tube being perfectly round, undamaged and cut square. Oval or scored tube will not seal reliably.
How Compression Fittings Work
A compression fitting consists of a body, a compression nut, and a ferrule (or two ferrules in some designs). The tube is inserted through the nut and ferrule, and the nut is tightened by hand then with a spanner. As the nut compresses, the ferrule deforms around the tube to create a gas-tight seal.
Unlike push-in fittings, compression fittings work with both plastic and metal tube. Once tightened they form a permanent connection — removing and reassembling compression fittings degrades the ferrule, so they are not designed for frequent disconnection.
Pressure and Temperature Ratings
Standard push-in fittings are rated to 10 bar working pressure at room temperature, with some heavy-duty versions rated to 16 bar. As temperature increases, the pressure rating typically drops, so check the manufacturer datasheet for your exact operating conditions.
Compression fittings — particularly those in brass or stainless steel — generally have higher pressure ratings, often 25 bar or more, and handle a wider temperature range. This makes them the standard choice for instrumentation, hydraulics and high-pressure pneumatic circuits.
When to Choose Push-In Fittings
- General-purpose pneumatic circuits operating below 10 bar
- Applications using metric OD polyurethane, nylon or polyethylene tube
- Where connections will be made and broken regularly (e.g. during setup and maintenance)
- Machine build projects where speed of assembly reduces labour cost
- Clean environments without heavy vibration
When to Choose Compression Fittings
- Pressures above 10 bar or in high-vacuum applications
- Metal tube connections
- High-vibration environments (compressor pipework, on-vehicle systems)
- Permanent installations where the connection will rarely be broken
- High-temperature applications beyond the push-in fitting rating
John Guest Push-In Fittings
John Guest is the market-leading brand for push-in pneumatic and fluid fittings. Their Speedfit and Superseal ranges offer exceptional reliability, with a wide selection of configurations including straight connectors, elbows, tee pieces, reducers, bulkheads and end stops. They are manufactured to exacting tolerances and widely trusted in food and beverage, medical and industrial applications.
Browse our range of John Guest push-in fittings to find the correct size and configuration for your project.
Frequently Asked Questions
Can push-in fittings be reused?
Yes, push-in fittings are designed to be connected and disconnected many times. Simply press the release collar and pull the tube free. However, you should inspect the tube end each time u2014 if it is scratched, oval or damaged, cut a fresh square end before reinserting.
At what pressure should I switch from push-in to compression fittings?
Standard push-in fittings are rated to 10 bar. Above this, or in high-vibration environments, compression fittings are the safer choice. Always check the specific rating for the fitting and tube combination you are using, as this varies between manufacturers.
Do compression fittings work with plastic tube?
Yes. Brass and stainless steel compression fittings work with both metal and plastic tube. For soft plastic tube, an insert sleeve is often used inside the tube end to prevent the ferrule from collapsing the tube wall during tightening.
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