Barrowford AGI Upgrade for Cadent | Rayden Engineering Ltd

BACKGROUND

Barrowford Above Ground Installation (AGI) is a High-Pressure (HP) gas site northeast of Burnley, operating at 32 barg with two Medium-Pressure (MP) outlets supplying the local area. Located within a constrained wooded boundary, the facility had become under-capacity, deteriorated and non-compliant with current Cadent operational and safety standards.

To meet future network demand and ensure long-term reliability, Cadent required a partial rebuild and full upgrade of the AGI’s mechanical, civil and electrical and instrumentation (E&I) assets.

A new installation was therefore constructed within the existing boundary, incorporating new filtration, metering, pre-heat systems, HP-MP regulation streams with integrated slam-shut protection, a fuel gas Pressure Reduction Unit (PRU), interconnecting pipework, civil infrastructure and a complete E&I renewal.

The new AGI was designed as a twin-stream system, replacing the original single-stream arrangement to deliver increased capacity, resilience and operational flexibility.

With no outage window available, all works – including installation, testing and commissioning – were completed while the existing AGI remained live, requiring a tightly phased build-and-changeover strategy to maintain uninterrupted gas supply.

Following commissioning, redundant assets were removed and the site reinstated. The scheme forms part of the Cadent Multi Activity Framework (MAF) for major upgrade projects across the North West.

ABOUT CADENT

Cadent Gas owns, operates and maintains the largest gas distribution network in the UK, ensuring the safe and reliable delivery of natural gas to over 11 million customers.

Their AGI upgrade programme supports long-term capacity planning, asset integrity, safety and regulatory compliance across the network.

SCOPE

Rayden Engineering Ltd (REL) was awarded the works from the Cadent Civil & Mechanical Multi Activity Framework (MAF) under a Call-Off Contract. Working as Principal Contractor under CDM 2015, REL delivered the mechanical, civil, E&I and Cathodic Protection upgrade of the Barrowford AGI.

Scope included:

Disinvestment: isolation & safe removal of redundant pipework, equipment & AGI assets.
Offsite Fabrication: new HP, MP & LP pipework spools & supports.
Package Equipment Installation: new filtration, metering, pre-heat & HP-MP / MP-LP pressure reduction systems.
Civil Works: new equipment foundations, pipe support bases, duct routes, draw pits, lighting bases and site modifications.

Interconnecting Pipework Installation: above ground & buried pipework, supports & tie-ins to live assets.
E&I & Control Systems: new power, instrumentation, telemetry & control/RTU configuration.
Cathodic Protection: integration of new buried assets to existing CP system with isolation joints, bonding & coating repairs.
Commissioning: phased commissioning & changeover to maintain continuous operation.

All works were completed within the existing boundary while the live AGI remained in operation.

SERVICES DELIVERED

The project required a two-phase build and commissioning strategy, enabling the existing AGI to remain live throughout. With no outage window available, REL delivered a phased installation and changeover sequence that maintained full operational continuity.

Project Management:

REL provided full project leadership to ensure safe, compliant and efficient delivery, including:

Site establishment, safety management, logistics planning & coordination with Cadent Operations.
Programme development & control aligned with key dates & milestones.
Procurement of materials, integration of free-issue equipment & full QA management.
Preparation & approval management of weld procedures & supporting documentation.
Interface management with Cadent, OEMs & specialist subcontractors (E&I, NDT, lifting, CP).
Submission of RAMS, Temporary Works, Traffic Management Plans & all SHEQ documentation.
Attendance at HAZCON, design reviews & project coordination meetings.

Offsite Fabrication:

All HP, MP and LP pipework spools were fabricated at the REL Workshop facility to minimise on-site work and maintain full quality control. Work included fabrication of filter inlet, filter outlet/heat-exchanger inlet & heat-exchanger outlet pipework in line with programme requirements.

Key activities included:

Welding all spools in accordance with Cadent approved procedures (GD/SP/PW/11).
NDT (radiography/ultrasonic), pressure testing & protective coating in compliance with GIS/P/A/10.
Preparation, handling & delivery of completed spools to site for installation.

Construction Works:

Construction activities were delivered in accordance with the approved programme, detailed design reports and Cadent specifications. All works were sequenced to maintain full operational continuity at the live AGI.

Mobilisation & Site Establishment:

- Setup of welfare & office facilities, temporary works, traffic management controls, access preparation & establishment of car park & laydown areas.

Deconstruction Works:

- Controlled removal of redundant 200mm & 150mm HP/MP pipework, boiler components, legacy meter/heat-exchanger stream pipework, temporary PRU connections & buried assets, including temporary supports & blanking.

Civil Works:

- Construction of reinforced concrete foundations for filter, heat-exchanger & fuel-gas PRU skids, designed for a 100-year life.
- Installation of above ground pipe supports for 150mm & 200mm HP pipework, plus below-ground supports for 200mm filter inlet/outlet runs.
- All excavations completed using hand-dig methods in accordance with Cadent SW2 procedures due to proximity to live HP/MP assets.
- Installation of access chambers (AC1 & AC2), duct routes, draw pits & cable management using twin-wall Rigiduct systems with EN124-rated covers.
- Construction of additional foundations including Ultrasonic Meter (USM), instrument kiosks, lighting columns & gate-switch assemblies.

Equipment Installation:

- Placement & alignment of filter, heat-exchanger & fuel-gas skids, lighting columns, gate-switch units & associated mechanical equipment in line with phased build sequence.

E&I Works:

- Installation of new power, instrumentation, telemetry & communications cabling, including terminations, testing & system integration.
- Works delivered in accordance with the Hazardous Area Assessment, including EX-rated equipment, earthing & bonding.
- Configuration of the KCT2v2 RTU, telemetry I/O & SCADA interfaces, & safe removal of redundant systems during Phase 2 changeover.

1. Cathodic Protection (CP) Works:

- Installation of isolation joints, bonding continuity & coating repairs to ensure compatibility with retained CP system.
- Completion of continuity & isolation testing to confirm compliance with the CP Design Report.

Pipe Support Foundations:

- Construction of above-ground & below-ground concrete supports for interconnecting HP/MP pipework.

Regulator Building Modifications:

- Installation of new 900mm access door, structural supports, louvres & core drilling.
- Removal & below-ground blanking of redundant 50mm fuel-gas supply & reinstatement of internal floor.

Pipework Installation & Testing:

Pipework installation was completed in accordance with approved designs and Cadent specifications, covering new HP, MP and LP gas systems and the boiler flow/return circuit.

Works followed a controlled sequence of excavation, installation, testing and reinstatement. Major mechanical equipment installed included fully twin-stream filter, heat-exchanger and regulator skids, replacing the former single-stream system.

High-Pressure (HP) Pipework:

- Installation of 150mm & 200mm carbon steel pipework connecting filter skid, heat exchanger skid & regulator streams, including above ground & buried sections.
- Works delivered to GD/SP/PW/11 & GD/SP/E/28, including Golden Weld on filter-outlet tie-in.
- Alignment, fit-up & installation of vent/purge points at isolation valves.

Medium-Pressure (MP) & Low-Pressure (LP) Fuel Gas Pipework:

- Installation of 63mm buried PE pipework feeding fuel gas PRU & boiler house.
- Excavation of hot-tap pit & connection to live main with 80mm hot-tap mechanical tee.
- Installation of 50mm above ground steel pipework between transition fittings & PRU/boiler interfaces.
- PE joints completed using electrofusion fittings, with inspection records maintained.

Boiler Flow & Return Pipework:

- Installation of 63mm buried insulated flow/return pipework & 50mm above ground steel connections between boiler house & heat-exchanger skid, in line with GD/SP/TR/18 & boiler vendor requirements.

Trenching, Bedding & Backfill:

- Excavation of trenches for pipework to programme, installation of sand bedding & formation of sand boxes prior to controlled backfill.

Alignment, Dimensional Checks & Tie-in Control:

- Dimensional verification completed prior to all tie-ins to ensure correct alignment with existing live assets.
- Temporary supports installed to safely control cut-outs & tie-in operations.

Testing & Inspection:

- Hydraulic & pneumatic testing of steel pipework; NDT (RT/UT) of all welds.
- Testing of PE pipework to CAD/PM/MSL/1, including electrofusion joint verification.
- Coating repairs & integrity checks on all buried steel sections.

Commissioning

Supported Cadent through all commissioning stages, ensuring safe startup & integration of the new AGI systems:

Pre-commissioning Preparation: system checks, boiler circuit filling, gas backfeed, purge operations & controlled pressurisation of new pipework.
Boiler & Pre-heat System Commissioning: startup of boiler house & functional proving of heat-exchanger circuit & controls.
Process Stream Commissioning: functional testing of inlet, filter, metering & PRU streams, with completion of Golden Weld transition.
E&I & Software Commissioning: telemetry integration, RTU/software configuration, instrument testing & alarms proving.
Stream Changeover: support through Cadent proving period for new regulator streams.
Handover: completion of commissioning records, ITPs & supporting documentation.

Completion & Reinstatement

Following successful commissioning & stream proving, REL completed all reinstatement, demobilisation & documentation activities in accordance with programme. Works included:

Removal & Decommissioning: remaining redundant assets, including HP inlet pipework, buried sections, filter skid foundations & legacy sandboxes.
Grouting: redundant below ground pipework.
Installation of Final Site Infrastructure: GRP handrailing, concrete footpaths, protective bollards & top-dressing of stone chippings across AGI compound.
Reinstatement of External Areas: laydown zones, welfare areas, access routes & landscaped sections affected by construction.
Demobilisation: of site compound & removal of all temporary works.
Completion & Submission: as-Built drawings, Databooks & all close-out documentation, including test packs, weld logs, NDT & coating records.

Regulatory & Compliance

All works were delivered in full compliance with applicable legislation, industry standards and Cadent specifications, including:

PSSR 2000: Pressure Systems Safety Regulations.
CDM 2015: Fulfilment of Principal Contractor Duties.
Health & Safety at Work Act 1974 & associated ACOPs.
DSEAR 2002: Dangerous Substances & Explosive Atmospheres Regulations.
IGEM/TD/13: Pressure Regulating Installations.
IGEM/SR/25: Hazardous Area Classification.
GD/SP/SSW/22: Safe Working Near HP Pipelines & AGIs.
GD/SP/TR/18 & GD/SP/TR/24: Design & Engineering Systems >7 Barg.
GD/SP/E/28: PRI Design & Equipment Requirements.

GD/SP/PW/11: Welding, Inspection & Testing of Steel Pipework.
CAD/PM/MSL/1: Jointing & Testing PE Pipework.
CAD/SP/E/68: Electrical, Instrumentation & Telemetry Requirements.
Cadent G19 Model: Tie-ins, Supports, Cut-outs & Construction Tolerances.
Cadent Golden Rules: FPSA Requirements & HAZCON Outputs.
Environmental & Waste Regulations: including EPR 2016.
ISO 9001, 14001, 45001, 3834-2 & EN 1090-1: REL Certified Management Systems.

OUTCOME

REL successfully delivered the Barrowford AGI upgrade, transforming an ageing, constrained installation into a modern, higher-capacity asset. A phased construction and commissioning strategy maintained continuous gas supply with no unplanned outages throughout the live works.

The new twin-stream AGI provides increased HP-MP capacity, improved metering performance, enhanced operational resilience and fully modernised E&I infrastructure in compliance with Cadent standards.

The project demonstrates our capability to safely deliver complex brownfield AGI upgrades within restricted live environments.

Cadent provided positive feedback on completion, recognising the technical quality of installation, disciplined teamwork and strong collaboration demonstrated throughout the project.