July 18, 2026 APM Electricals

110mm Soil Pipe Fittings — Pan Connectors, Socket Plugs, Bends, and Vent Cowls for UK Plumbers

What Is 110mm Soil Pipe Used For?

110mm soil pipe — also called 4-inch soil pipe — is the standard diameter for above-ground soil and waste drainage in UK domestic and commercial buildings. It carries waste from toilets, soil stacks, and branch connections to the underground drainage system. Every new-build and refurb toilet installation uses 110mm pipework, which is why fittings in this size are a trade staple for plumbers and builders.

The two main materials are:

MUPVC (modified unplasticised PVC) — standard soil pipe, UV-stable, used externally and internally
Grey pushfit — faster to install than solvent weld; no primers or solvents required

Soil pipe fittings at 110mm cover a wide range of connection types: pan connectors (WC to soil pipe), socket plugs (capping off unused sockets), bends (direction changes), and vent cowls (stack ventilation). Understanding which fitting to use — and when — is essential knowledge for anyone doing toilet or drainage work.

Pan Connectors: WC to Soil Pipe

The pan connector joins the toilet outlet to the 110mm soil pipe. It must accommodate the distance and angle between the WC pan outlet and the soil pipe socket — these vary significantly between pans, so a flexible pan connector is the professional's choice.

The Embrass Peerless Flexible Pan Connector 100/110mm accepts both 100mm and 110mm spigot outlets and flexes to adjust for horizontal offset, height variation, and slight angular misalignment. On a bathroom refurb where the new pan doesn't land exactly where the old one did, this connector saves time and avoids cutting and re-routing soil pipe.

Key points when fitting pan connectors:

Lubricate the rubber seal with washing-up liquid — never petroleum-based lubricants (degrade rubber)
Ensure the WC outlet pushes fully into the socket — a partial fit causes slow leaks and sewer gas ingress
The flexible portion should not be under tension when the WC is fixed to the floor
100/110mm flexible connectors suit the majority of close-coupled and back-to-wall cisterns

Embrass Peerless Pan Connector Flexible 100/110mm UK

Flexible pushfit pan connector for 100mm and 110mm WC outlets. Accommodates offset and height variation — essential on refurb jobs. Rubber-sealed pushfit socket for tool-free installation. WRAS-approved materials.

£7.49

Socket Plugs: Capping Unused Soil Pipe Sockets

A socket plug seals an open 110mm socket on a branch, tee, or boss — wherever a connection has been made but is not currently in use. They're one of those fittings that every plumber carries because you never know when you'll need to cap off an access point or seal a decommissioned connection.

The Aquaflow 110mm Pushfit Waste Socket Plug Grey is a simple, reliable pushfit plug for grey MUPVC soil pipe sockets. It pushes into any standard 110mm socket and seats against the rubber seal to give a watertight, odour-proof seal. Unlike solvent-weld plugs, it can be removed and reinserted without damaging the socket — useful on drainage systems where access may be needed.

Common uses for 110mm socket plugs:

Capping unused branches on soil tees before branch lines are connected
Sealing a socket temporarily during drainage pressure testing
Decommissioning a WC outlet branch when moving a toilet
Sealing access sockets on inspection bends

Aquaflow 110mm Pushfit Waste Socket Plug - Grey

Pushfit socket plug for 110mm grey MUPVC soil pipe. Seals open sockets on branches, tees, and inspection fittings. Removable and reusable — ideal for pressure testing and temporary sealing. Standard 110mm socket fit.

£2.03

Soil Pipe Bends: Direction Changes at 110mm

110mm bends are used to change direction on the soil stack or branch runs. The standard angles are 90° (knuckle bend) and 92.5° — the 92.5° is the technically correct angle for a WC branch connection to a vertical stack, as it provides a slight downward flow angle to prevent backpressure at the trap.

The difference between a single socket bend and a double socket bend:

Single socket (SS) — one socket end, one plain/spigot end. Used where one end connects into a length of plain-end soil pipe
Double socket (DS) — sockets at both ends. Used where you're connecting two socketed pipes or fittings without cutting a plain end

The 110mm 90° Single Socket Knuckle Bend Grey is the most common bend for domestic soil stacks — used where the stack transitions from vertical to horizontal (offset bends) or where a branch run changes direction. Grey pushfit means no priming or solvents; the rubber seal provides a secure, maintenance-free joint.

110mm 90° Single Socket Knuckle Bend Grey - Soil Pipe

Single socket 90° knuckle bend for grey pushfit 110mm soil pipe. For direction changes on soil stacks and branch runs. Pushfit rubber seal — no solvent weld required. Compatible with standard 110mm grey MUPVC plain-end pipe.

£5.88

Vent Cowls: Terminating the Soil Stack

Every soil stack must be open at the top to ventilate the drainage system — this prevents trap siphonage and allows sewer gas to escape safely. Building Regulations Part H requires open-ended stacks to terminate with a vent cowl at least 900mm above any openable window within 3m horizontally.

A vent cowl fits over the open top of the soil pipe stack and prevents birds, insects, and debris from entering while allowing free airflow. It is not an air admittance valve (AAV) — a vent cowl simply caps and screens an open stack vent.

The 110mm Vent Cowl Black is a simple, durable cap for open-vented soil stacks. It fits standard 110mm soil pipe and is made from UV-stabilised black MUPVC — suitable for external use in all UK weather conditions. No tools required; the cowl pushes over the pipe end and is held by friction fit.

Vent cowl installation checklist:

Stack must terminate minimum 900mm above any openable window within 3m (Part H)
Use black cowl on black stack, grey cowl on grey stack for a clean finish
Do not use a vent cowl if the stack terminates in a location where an AAV is required (internal stacks)
Ensure the pipe end is clean and square before fitting

110mm Vent Cowl Black - Soil Pipe

Black MUPVC vent cowl for 110mm soil pipe stack terminations. Prevents bird and debris ingress while maintaining open-stack ventilation. UV-stabilised for external use. Pushfit installation — no tools or adhesive required. Part H compliant open vent termination.

£2.59

Black vs Grey Soil Pipe: What's the Difference?

Both colours are MUPVC and mechanically identical — the choice is aesthetic and application-based:

Black is traditional for external soil stacks and is still the most common on older housing stock. Black is also standard for underground-to-above-ground transition fittings.
Grey is more common on modern builds and is preferred internally — it blends with grey duct systems and fits most grey pushfit coupling systems.

Never mix pushfit grey and solvent-weld fittings in the same run without a purpose-made adaptor — the socket geometries differ.

Pushfit vs Solvent Weld at 110mm

For most above-ground soil pipe work, pushfit is now the trade-standard choice:

Factor	Pushfit	Solvent Weld
Installation speed	Fast — hand-fit joints	Slower — prime, solvent, cure time
Dismantling	Removable	Permanent
Movement accommodation	Yes — thermal expansion absorbed	No — fixed joint
External use	Yes	Yes
Pressure testing	OK for drain testing	OK for drain testing

Solvent weld is still used on older systems and where pushfit fittings are unavailable for a specific configuration. On new installations, pushfit is almost always specified.