Unions

Malleable Iron Unions are three-part threaded fittings designed to connect two sections of pipe while allowing the system to be easily disconnected without cutting or disturbing the pipework. They are widely used in fire protection, plumbing, heating and industrial systems where maintenance access or future modification is required.

 
Manufactured from malleable iron and typically supplied with BSPT threaded ends, they provide a strong, leak-resistant and reusable joint solution.

Key Features

• Three-part demountable union design 
• Female BSPT threaded connections (typical configuration) 
• Allows easy disconnection and reassembly of pipework 
• Manufactured from durable malleable iron 
• Strong, pressure-resistant sealing surfaces 
• Suitable for maintenance-friendly installations 
• Available in black and galvanised finishes

Product Description

Unions are designed to provide a secure pipe connection that can be repeatedly assembled and disassembled without damaging the pipework. Unlike standard threaded fittings, they incorporate a central union nut and mating faces that compress together to form a tight mechanical seal when tightened.

The sealing action is achieved through precisely machined mating faces—often incorporating a softer seating material such as brass within the assembly depending on specification—which compress under tightening to create a reliable, leak-resistant joint. This makes unions particularly valuable in systems that require periodic maintenance or component replacement.

 
Manufactured from malleable iron, these fittings offer excellent mechanical strength combined with resistance to shock and vibration. This ensures durability in demanding environments while maintaining the ability to be repeatedly dismantled and reassembled without degradation of performance.

 
Typically featuring BSPT (British Standard Pipe Taper) female threaded ends, unions are installed into standard threaded pipe systems using conventional sealing compounds or PTFE tape on the threaded joints. The union itself then provides the serviceable break point in the system.

 
These fittings are widely used in fire sprinkler systems, boiler installations, HVAC systems, compressed air networks and general industrial pipework. Their ability to isolate sections of pipework without cutting makes them essential for equipment connections, pump sets, valves and maintenance access points.

 
Available in Black (self-colour) for internal or painted systems and Hot Dip Galvanised (HDG) for enhanced corrosion resistance in external or more aggressive environments, they offer flexibility across a wide range of applications.

Applications

Ideal for fire sprinkler systems, plumbing, heating, boiler connections, HVAC installations, compressed air systems and industrial pipework where removable and serviceable threaded connections are required.

We offer nationwide next working day delivery on stocked products for orders placed before 12:00 pm, subject to stock availability.

Delivery charges are calculated based on your order's size, weight and destination and will be shown at checkout where applicable.

Some oversized, bespoke or non-stock items may require additional lead time. If this affects your order, we'll let you know as soon as possible.

Collection is available from our warehouses in Rochdale, Halesowen and East Kilbride, subject to stock availability. Please check the individual product listing for collection availability.