Compression, Push-Fit, and End Feed Fittings: Which to Use and When

Compression, Push-Fit, and End Feed Fittings: Which to Use and When

Three main joining methods dominate UK copper and plastic pipework installations: compression fittings, push-fit fittings, and end-feed (solder) fittings. Each has a different assembly process, cost profile, and appropriate use case. Getting this decision right on-site saves time and avoids callbacks — this guide explains the differences and when to specify each type.

Compression Fittings

A compression fitting uses a threaded union nut and a soft copper or brass ring (the olive) to create a watertight seal. As the nut is tightened, the olive deforms slightly and grips the pipe outer diameter. No heat, no flux, no solder — just spanners.

Assembly procedure:

1. Cut the pipe square with a pipe slice or hacksaw (no burr — deburr with a deburring tool or file)
2. Slide the nut, then the olive onto the pipe
3. Push the pipe fully into the fitting body until it seats against the internal stop
4. Hand-tighten the nut, then use a spanner — typically 1.25 turns past hand-tight for copper; consult manufacturer instructions for plastic inserts

When to use compression fittings:

• Where a gas torch cannot safely be used: near timber joists, insulation, plastic materials, gas pipes, or in enclosed voids where heat dispersal is an issue
• Where the joint needs to be demountable for future maintenance (boiler connections, isolation valves, gate valves)
• Connections to appliances, meters, and valves where thread interfaces exist alongside pipe runs
• Any situation where a fast, inspectable joint is needed without waiting for solder to cool

Limitations: More expensive per fitting than end-feed equivalents. Bulkier than other joint types — harder to conceal in tight spaces. Overtightening splits the olive; undertightening drips. Requires access for two spanners (one on the fitting body, one on the nut).

Common sizes: 8mm, 10mm, 15mm, 22mm, 28mm, 35mm, 42mm (15mm and 22mm account for the majority of domestic installs). Available in full-flow bodies (straight coupling, elbow, tee) and reduced-flow configurations, and in both copper-to-copper and male/female iron (BSP) thread ends.

Push-Fit Fittings

Push-fit fittings use an internal grab ring (a toothed stainless steel collet) and an O-ring seal. The pipe is simply pushed into the fitting body — the collet bites into the pipe and resists pull-out, while the O-ring provides the waterproof seal. No tools required for connection; a disconnect tool (or collar) is needed to release.

Assembly procedure:

1. Cut the pipe square and deburr
2. For plastic pipe (HEP2O, JG Speedfit, Hep2O): insert a metal pipe insert (liner/stiffener) into the pipe end before pushing into the fitting — this prevents the collet crushing the softer pipe. This step is essential; omitting it causes joint failure.
3. Push the pipe firmly into the fitting until it seats against the internal stop — you should feel and sometimes hear a click as the collet engages
4. Give a firm tug to confirm the pipe is locked in

When to use push-fit fittings:

• Plastic pipe runs (barrier pipe, MDPE, HEP2O) — push-fit is the dominant joining method for plastic central heating pipe
• Speed: push-fit is significantly faster to install than either compression or end-feed — valuable when labour cost per joint matters
• Copper pipe where heat cannot be used and speed is a priority
• Accessible locations only: push-fit joints on copper may micro-creep over decades under mechanical stress — not ideal for joints buried in screed or behind walls without a service access point. Plastic barrier pipe with push-fit joints is routinely embedded in screed for underfloor heating.
• DIY or home-owner-accessible minor repairs

Limitations: Higher per-fitting cost than end-feed. Not suitable for use above 95°C (check manufacturer ratings for hot water systems). The grab ring can be damaged by repeated insertion and removal. Plastic inserts must be used with plastic pipe without exception.

Major UK brands: JG Speedfit, Hep2O (Wavin), Conex Bänninger. Available in 10mm, 15mm, 22mm, 28mm, and barrier-pipe sizes for UFH manifold connections.

End-Feed (Capillary/Solder) Fittings

End-feed copper fittings are the lowest-cost copper joining method and the most compact. The fitting is a plain copper sleeve with no pre-loaded solder — the installer applies flux to the pipe end, inserts it into the fitting, and then applies heat from a propane or MAPP gas torch. The solder (typically lead-free plumbing solder wire) is then applied to the joint gap and wicked in by capillary action. When done correctly, solder is drawn fully into the joint space, creating an extremely strong, low-profile joint.

Assembly procedure (end-feed):

1. Cut and deburr the pipe. Clean the outside of the pipe end and inside of the fitting with emery cloth or wire wool until bright copper shows — oxide prevents solder adhesion.
2. Apply flux (tinning flux or standard plumbing flux) to the pipe end and inside the fitting.
3. Assemble the fitting and apply heat evenly — move the torch around the joint, not at a single point. The fitting should be hot enough that solder melts on contact with the joint, not from the flame directly.
4. Apply solder wire to the joint gap (not to the flame) until a bright ring of solder appears all around the gap. Stop: overfilling wastes solder and restricts bore.
5. Allow to cool undisturbed. Wipe the joint with a damp rag to remove flux residue — flux left in place is corrosive over time.

Yorkshire (integral solder ring) fittings are a variant where solder is pre-loaded in a groove inside the fitting. Heat alone is needed — no separate solder wire. Slightly more expensive than end-feed but faster to use and good for overhead or awkward positions where handling solder wire with a torch simultaneously is difficult.

When to use end-feed/capillary fittings:

• Copper pipework in accessible areas where a gas torch can be used safely
• High-volume work where the cost saving per fitting is significant (large mechanical or commercial installs)
• Where a compact, low-profile joint is needed (concealed within wall chases, in tight manifold spaces)
• Any situation where long-term joint integrity without mechanical adjustment is the priority

Limitations: Requires a gas torch and competence with soldering — not suitable for DIY in most situations. Cannot be used near gas pipes or timber without fire protection measures. Requires the pipe to be dry before soldering: even residual water in a pipe will prevent the joint reaching soldering temperature. Must not be used on live gas pipework without Gas Safe registration and the appropriate gas pipework qualifications.

Quick Comparison Summary

Pipe Fittings at APM Plumbing & Electrical

APM stocks all three fitting types across the full range of domestic pipe sizes. Our compression fittings range covers 8mm to 42mm in both full straight and reduced configurations. Push-fit ranges include JG Speedfit and Hep2O for 10mm to 28mm plastic and copper pipe, including barrier pipe and UFH-grade fittings. Our end-feed and Yorkshire solder ring copper fittings include Embrass Peerless Atomic EF and compatible ranges for 8mm to 54mm pipe, available individually or in trade packs.

Browse our pipe fittings collection or visit our Acton trade counter. Trade orders placed before 2pm ship same day across London and the South East.