Manufacture & Fabrication
Radius Subterra delivers specialist manufacture and fabrication of bespoke pipeline fittings and assemblies engineered to suit specific asset, operational and installation requirements.
Working across gas, water and industrial networks, components are designed and built to suit host pipe material, diameter, wall thickness and operating conditions, supporting both planned works and live network operations.
Our bespoke PE fabrication capability enables complex polyethylene pipe assemblies to be produced off-site using controlled butt fusion and electrofusion processes. Fabrications can incorporate mitred butt-fused joints, couplers, reducers, tapping tees, and low-profile branch saddles within a single build, creating ready-to-install configurations tailored to the connection or modification.
Designer and bespoke-sized and branch saddles can also be manufactured for non-standard pipe sizes or constrained locations. In many cases, these solutions provide a practical alternative to more invasive intervention methods, avoiding decommissioning, large excavations, or extensive reinstatement.
For metallic pipelines, Radius Subterra manufactures and supplies large-diameter fittings including flange adapters, under-pressure tees, end caps, and grouted tees and sleeves.
- Flange adapters are produced to suit the measured outside diameter of the host pipe, supported by on-site callipering to ensure accurate fit-up and reliable sealing.
- Under-pressure tees provide a sealed interface for live drilling and branch installation while the main remains operational.
- End caps are used to safely terminate pipelines during maintenance, testing, staged works, or decommissioning activities.
- Grouted tees and sleeves provide structural, pressure-retaining solutions without the need for welding.
Radius Subterra provides a complete end-to-end service including consultation, CAD design, manufacture, installation, and full reporting. Managing design, fabrication, and delivery under a single scope ensures dimensional accuracy, controlled installation, and compliance with relevant industry standards.
This integrated approach reduces interface risk, improves programme efficiency and provides asset owners with assurance that each component has been engineered and installed in line with operational requirements and long-term performance expectations.
Key Benefits
Bespoke sizing for accurate fit-up
Components are manufactured to match the actual pipe diameter, material and wall thickness, ensuring accurate fit, reliable sealing, and reduced need for on-site modification or adjustments.
Engineered solutions for site constraints
Fabrications are designed to suit restricted access, congested excavations, and complex layouts, providing practical connection solutions where standard fittings or conventional methods cannot be installed easily.
End-to-end delivery
A single coordinated service, from consultation and CAD design to manufacture, installation and reporting, ensures quality control, consistency, and efficient progression from planning to completion.
Manufacture & Fabrication technologies
Engineered manufacture and fabrication technologies delivering bespoke pipeline fittings and assemblies that support connections, repairs and live network operations across all asset types.
Bespoke polyethylene (PE) fabrications
Bespoke PE fabrications are delivered by Radius Subterra for use across all industries, providing pre-engineered polyethylene pipe assemblies tailored to specific site and installation requirements. Fabrications can be produced across a range of pipe diameters, SDRs, and PE material grades, enabling complex pipework arrangements to be manufactured off-site and installed as a single, integrated solution.
Assemblies can incorporate butt fusion and electrofusion joints, including mitred butt-fusion angles to achieve accurate changes in direction or alignment. Electrofusion components such as couplers, tapping tees, and branch saddles can be integrated into the fabrication, reducing on-site jointing and simplifying installation.
A key application of Radius Subterra’s bespoke PE fabrications is the integration of low-profile branch saddles into purpose-designed pipe configurations. Traditional tee connections can be physically large and restrictive, particularly in congested excavations or chambers. Radius Subterra’s low-profile branch saddles provide a significantly reduced physical footprint, delivering meaningful space savings and lowering excavation and reinstatement costs.
Bespoke PE fabrications are also used for the manufacture of gas manifold systems and meter outlet pipework, where compact layouts, accurate alignment and controlled assembly are essential. Multiple fabrication elements, including mitred sections, branch connections, and tapping tees, can be combined into a single build to produce a compact, ready-to-install assembly.
Radius Subterra also provides CAD drawings and full fabrication reporting, including dimensional drawings for approval and comprehensive build records. By combining design, fabrication, and documentation, we deliver controlled, space-efficient PE fabrications that support reliable installation and long-term asset performance.
Bespoke-sized branch saddles
Radius Subterra offers an in-house bespoke branch saddle service, delivering engineered branch saddle solutions for all sizes of polyethylene (PE) pipe across all industries. Where standard fittings are unsuitable due to pipe diameter, SDR, geometry, or site constraints, bespoke and designer branch saddles are developed to meet specific operational and installation requirements.
Using a designer branch saddle can deliver significant programme and cost savings. In many cases, the only alternative solutions would be to decommission the main or undertake a flowstopping and cut-out operation. Both approaches introduce greater disruption, either through supply interruption or by requiring larger excavations, longer site durations, and more complex reinstatement. A bespoke branch saddle can avoid or significantly reduce these impacts by enabling a controlled branch connection without full main isolation or extensive excavation.
Designer branch saddles are engineered around the host pipe and connection requirement, allowing installation in constrained locations and on non-standard pipe sizes where off-the-shelf products cannot be used. Designs are produced to meet relevant EN and GIS requirements, providing assurance that mechanical performance and joint integrity align with industry standards.
Radius Subterra provides an end-to-end service, including technical consultation, design development, manufacture, installation, and full reporting. Each bespoke saddle is supported by CAD design, manufacturing records, and installation documentation to support compliance and assurance. Post-installation, we provide ongoing technical support to ensure long-term asset performance assurance and operational reliability.
Flange adapters
Flange adapters up to 900 mm (48″) are manufactured and supplied by Radius Subterra to create accurate, secure connections between large-diameter pipelines and flanged valves, fittings, or pipework. They are used routinely on everyday pipeline connections and are equally effective on older or non-standard mains where achieving a reliable fit depends on accurate dimensional control.
Adapters are manufactured to suit the actual outside diameter of the pipe, ensuring correct compression, alignment, and sealing performance. This is particularly important on large-diameter assets where nominal sizes, coatings, or manufacturing tolerances can vary.
To support accurate manufacture, Radius Subterra offers an on-site callipering service to confirm the pipe outside diameter prior to fabrication. This ensures each flange adapter is produced specifically for the measured host pipe dimension, reducing installation risk and avoiding forced fit or on-site modification.
Large-diameter flange adapters are commonly used during network modifications, valve installations, flowstopping activities, and asset replacement works where a flanged interface is required. Accurate dimensional matching ensures correct bolt-up, even gasket compression and a secure, leak-tight connection.
Radius Subterra provides a fully integrated service, covering site measurement, bespoke manufacture, installation, and full reporting. Managing measurement, fabrication and installation under a single scope ensures controlled execution, reliable sealing performance and confidence that flanged connections are delivered safely and in line with industry expectations.
Under-pressure tees
Under-pressure tees (UPTs) up to 900 mm (48″) are manufactured and supplied by Radius Subterra to enable controlled connections to live pipelines without supply interruption. These fittings are engineered for under-pressure (hot tapping) operations, providing a stable, sealed interface that allows drilling and branch connections while the main remains operational.
Each UPT is designed to suit the host pipe material, diameter, wall thickness, and operating conditions. The design focuses on maintaining sealing integrity throughout the drilling process and managing loads introduced during live drilling and connection works, ensuring the connection remains secure during installation and for the life of the asset.
Manufacturing UPTs for large-diameter pipelines requires accurate dimensional control and a detailed understanding of live-network behaviour. Radius Subterra manufactures under-pressure tees to suit the actual outside diameter of the host pipe, which is particularly important on large or legacy mains where nominal sizes may not reflect true dimensions. This supports reliable fit-up, consistent sealing and predictable installation outcomes.
Under-pressure tees are widely used for live network modifications, new connections, asset installations, and other interventions on operational mains. They are also key components for flowstopping activities, providing the access point required to install isolation equipment while the main remains live. UPT installations reduce disruption, limit excavation scope and shorten overall programme duration.
Radius Subterra provides a fully integrated service, covering technical consultation, design, manufacture, installation, under-pressure drilling and full reporting. Managing the fitting and live-network operation under a single scope ensures safe, controlled execution and reduces interface risk across all project stages.
End caps
Radius Subterra manufacture and supply end caps up to 900 mm (48″) to deliver a secure means of terminating large-diameter pipelines during planned works. These fittings are used where a pipe end must be safely sealed to allow maintenance, modification, testing, or staged construction activities to proceed in a controlled manner.
End caps are designed to suit the host pipe material, diameter, wall thickness, and operating conditions. They provide a robust, pressure-rated closure capable of withstanding internal loads and maintaining sealing integrity for the duration of the works. Designs can be configured to suit a range of connection methods and site constraints, supporting controlled installation on large-diameter assets.
Manufacturing large-diameter end caps requires accurate dimensional control to achieve correct fit and dependable sealing. Radius Subterra supplies end caps manufactured to suit the actual outside diameter of the pipe, which is particularly important on large or legacy assets where nominal sizes may not reflect expected dimensions. This approach supports predictable installation and reduces the risk of leakage or forced fit on site.
End caps are commonly used to enable pressure testing, isolation for maintenance or repair, and the decommissioning of sections of main, where pipelines must be safely sealed and left out of service. They are also used in conjunction with flowstopping operations, allowing isolated sections to be securely capped once cut.
Radius Subterra provides a fully integrated service, covering design support, manufacture, installation, and full reporting. Managing supply and installation under one coordinated scope ensures safe execution, reduced interface risk and confidence that large-diameter terminations meet industry and asset owner requirements.
Grouted tees and sleeves
Grouted tees and grouted sleeves are manufactured and supplied by Radius Subterra for use on metallic pipelines where a structural, sealed interface is required without welding to the parent main. These fittings are installed externally around the pipe, with the annular space filled with a high-strength grout system to create a secure mechanical bond and pressure-retaining seal.
Grouted tees create a connection point on a live main for under-pressure drilling and branch installation, while grouted sleeves provide reinforcement or repair to damaged or deteriorated pipe sections. Both solutions are widely used where maintaining supply is essential and hot work is not practical or permitted.
Each fitting is manufactured to suit the host pipe diameter, wall thickness and operating conditions, ensuring correct fit and sealing performance once installed. This is particularly important on large-diameter or legacy metallic mains where dimensional accuracy and load distribution are critical to long-term performance.
Radius Subterra delivers a complete service including manufacture, supply and installation of grouted tees and sleeves. These fittings are commonly deployed as part of live network interventions, including repair works, new branch connections, and as enabling components for flowstopping procedures.
By managing design, manufacture and installation under a single scope, Radius Subterra ensures controlled execution, reduced interface risk and confident delivery of structural, pressure-rated solutions. Comprehensive reporting and documentation are provided to support quality assurance and asset records, ensuring the operation is completed in a controlled and compliant manner.
Completion plugs
Completion plugs are manufactured and supplied by Radius Subterra for use with stopple tees and under‑pressure fittings. Completion plugs provide a pressure-retaining seal once stoppling or intervention works have been completed, allowing the fitting to remain in situ without the need for sacrificial valves.
Available in multiple configurations to suit different stopple machines and operational requirements, plugs can be manufactured to match bespoke tee designs and outlet dimensions. This ensures compatibility with the chosen isolation method and maintains the integrity of the main once operations are finalised.
Completion plugs are typically installed following a stopple or under-pressure drilling operation, providing a permanent mechanical seal within the branch outlet. Designs include screw-type, pin-type and mechanical locking configurations, selected based on machine compatibility and operational preference.
Plugs are manufactured with full material traceability and can be produced to suit a wide range of outlet diameters. Where required, bespoke configurations are available to align with specific network standards or project requirements.
As part of a wider intervention scope, Radius Subterra supports the complete process, from tee manufacture and installation, through isolation and drilling, to final plug installation and completion reporting, delivering a fully managed solution with documented assurance for gas and water network operators.
Our other solutions
Explore other Radius Subterra solutions designed to enhance safety, efficiency and long‑term performance.
Under Pressure Connections
Pre-Insulated Pipework
Pressure Testing
Pipework Installation & Mainlaying
Pipe Cutting
Engineering and Project Management
Pipe Lining
Pipeline Repair & Maintenance
Flowstopping
Our other solutions
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Under Pressure Connections
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Pipeline Repair & Maintenance
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Under Pressure Connections
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Pipeline Installation & Mainlaying
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Pre-Insulated pipework
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Pressure Testing
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Pipe Cutting
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Manufacturing/ Fabrication
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Engineering & Project Management
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Pipe Lining
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Case Studies
Discover the prowess of Radius Subterra through our latest case studies.
Witness how we excel in tackling intricate pipeline challenges with innovative solutions and state-of-the-art technology. Stay tuned for more videos showcasing our commitment to engineering excellence.
Faced with severe leaks in a critical 1500mm trunk main, Radius Subterra provided an innovative pipeline rehabilitation solution using their close-fit PE liner system. This approach restored the pipeline’s integrity
Discover how Radius Subterra’s precision engineering revitalises a historic London waterway with cutting-edge pipeline solutions, installing a bespoke branch saddle onto a live water main in Finsbury Park. This job
Radius Subterra partnered with Anglian Water to solve leak issues in a hard-to-reach 10” water pipeline in East Anglia. Using their innovative Rolldown & Slipline method, Subterra maximised pipe bore
In February an accidental incident occurred that resulted in a 10” gas main being damaged, and a hole being drilled into the main. The incident was near to the main
Case Studies
Discover how Radius Subterra delivers safe, innovative and technically assured solutions across the UK’s most challenging pipeline environments.
Faced with severe leaks in a critical 1500mm trunk main, Radius Subterra provided an innovative pipeline rehabilitation solution using their close-fit PE liner system. This approach restored the pipeline’s integrity
Discover how Radius Subterra’s precision engineering revitalises a historic London waterway with cutting-edge pipeline solutions, installing a bespoke branch saddle onto a live water main in Finsbury Park. This job
Radius Subterra partnered with Anglian Water to solve leak issues in a hard-to-reach 10” water pipeline in East Anglia. Using their innovative Rolldown & Slipline method, Subterra maximised pipe bore
What our client’s say about us
Why choose Radius Subterra?
Trusted expertise, engineered solutions and a service approach shaped around your challenges.
For decades we’ve supported utility networks in the UK and beyond with safe, reliable and efficient pipeline services. Our teams combine technical knowledge, industry-leading equipment and a problem-solving mindset to deliver high-quality outcomes with minimal disruption. Whether planned works or complex operational challenges, we provide proven capability and dependable support.
Decades of expertise
With deep roots across the wider Radius Group and extensive experience in live gas, water, biogas and pipeline rehabilitation operations, our teams bring exceptional hands-on knowledge to every project. We understand the pressures faced by network operators and contractors and deliver work that is safe, compliant and technically robust from start to finish.
Committed to quality and safety
Safety underpins every service we deliver. Our work follows industry standards, rigorous internal procedures and environmental best practice. From accredited techniques to specialist equipment, we ensure consistent quality while reducing risk, waste and unnecessary disruption across gas, water and biogas networks.
Minimising disruption
Our specialist techniques, including under-pressure connections, flowstopping and trenchless rehabilitation, allow essential works to continue while maintaining customer service, protecting highways and minimising community impact. Reduced excavation and streamlined operations, support faster reinstatement and lower overall disruption.
Innovation and customisation
From bespoke branch saddles to tailored fittings for non-standard assets, innovation is central to our approach. We engineer solutions to suit each site, material and operating condition, enabling safer, faster and more cost-effective outcomes across complex project environments.
Safety and sustainability
We champion safe working and long-term sustainability. Our methods reduce carbon, excavation material, traffic disruption and reinstatement, while modern equipment and ongoing training create a safer environment for teams and the public. Every project is designed and delivered with environmental responsibility and operational resilience in mind.
Decades of expertise
With deep roots across the wider Radius Group and extensive experience in live gas, water, biogas and pipeline rehabilitation operations, our teams bring exceptional hands-on knowledge to every project. We understand the pressures faced by network operators and contractors and deliver work that is safe, compliant and technically robust from start to finish.
Committed to quality and safety
Safety underpins every service we deliver. Our work follows industry standards, rigorous internal procedures and environmental best practice. From accredited techniques to specialist equipment, we ensure consistent quality while reducing risk, waste and unnecessary disruption across gas, water and biogas networks.
Minimising disruption
Our specialist techniques, including under-pressure connections, flowstopping and trenchless rehabilitation, allow essential works to continue while maintaining customer service, protecting highways and minimising community impact. Reduced excavation and streamlined operations, support faster reinstatement and lower overall disruption.
Innovation and customisation
From bespoke branch saddles to tailored fittings for non-standard assets, innovation is central to our approach. We engineer solutions to suit each site, material and operating condition, enabling safer, faster and more cost-effective outcomes across complex project environments.
Safety and sustainability
We champion safe working and long-term sustainability. Our methods reduce carbon, excavation material, traffic disruption and reinstatement, while modern equipment and ongoing training create a safer environment for teams and the public. Every project is designed and delivered with environmental responsibility and operational resilience in mind.
Contact us
Ready to progress your next pipeline project?
Radius Subterra’s specialist engineering teams are here to support you with safe, efficient and technically assured solutions across every stage of the asset lifecycle.
Get in touch by phone or email to discuss your requirements and speak directly with our experts.
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