Armstrong Industrial: Gas has supplied two additional 3MW modular boiler houses for a major Irish gas interconnector, increasing installed pre-heating capacity from 9.5MW to 15.5MW.
The equipment was delivered as an extension to a system Armstrong supplied in 2022. The new units had to be integrated with the two existing boiler houses and the site’s master control panel, adding another 6MW of heating without turning the upgrade into a separate plant operating alongside the original installation.
Pre-heating is required before high-pressure natural gas passes through pressure reduction. As pressure falls, the gas temperature can also drop, so heat is added upstream to keep the outlet temperature above the site’s operating requirement after the pressure-reduction stage.
The interconnector is designed to maintain gas leaving the site at more than 2°C. Boiler output is modulated against the process load, allowing the heating system to follow changes in gas flow instead of running continuously at full capacity.
The additional boiler houses support an increase in stated interconnector capacity from six million to 6.9 million standard cubic metres of gas per day. The site forms part of Ireland’s gas import infrastructure from the United Kingdom, so the heating upgrade sits inside a wider capacity increase rather than operating as a stand-alone building-services project.
Raising gas throughput affects more than the pipeline itself, because pressure-control equipment, heating duty, metering, controls, safety systems, and downstream operating limits must remain aligned if the higher flow is to be available reliably.
The project was delivered on a compressed programme. Armstrong received the tender request in October 2024 and submitted its full return within ten days, followed by responses to technical clarifications the next month. A purchase order arrived in February 2025, with design calculations and indicative drawings submitted within a month and design approval secured in April.
Procurement began immediately after approval, and manufacturing started in July 2025 at Armstrong’s Droitwich facility. Each boiler-house enclosure measured around 10 metres long, 3.7 metres wide, and 3.2 metres high before the flue terminals were added, making factory space and lifting capacity practical constraints during assembly.
Off-site manufacture allowed boilers, pumps, controls, pipework, electrical systems, and structural enclosures to be brought together before delivery. Armstrong’s industrial systems operation is built around the same packaged approach, combining structural elements, process equipment, controls, electrical gear, and environmental enclosures before equipment reaches site.
The completed boiler houses were ready for customer inspection at Droitwich in September 2025 and transported to site during the same month. Armstrong’s service team commissioned the units in October, meeting the required end-of-month handover before the planned increase in gas flows.
The design used standardised boiler, pump, and control arrangements as the basis for a customer-specific package. That approach reduces the amount of engineering that has to be recreated for every project while preserving the interfaces that matter on site, including electrical supplies, pipe connections, controls integration, safety systems, and the dimensions of the enclosure.
Low-NOx condensing boilers were specified for the new units. Condensate is neutralised to a pH between 6 and 8 before discharge, while gas valves are adjusted during commissioning to achieve the boiler manufacturer’s recommended carbon-dioxide setting, with the resulting values recorded.
Those details sit below the headline megawatt figure but are central to operating packaged heating plant on critical gas infrastructure. Combustion performance, condensate handling, controls, and redundancy determine whether nominal capacity remains available through changing load and weather conditions, particularly when the heating system is supporting a network asset rather than a discretionary process.
Armstrong’s Droitwich operation is set up for this type of modular construction. The company describes the site as a systems manufacturing centre for packaged plantrooms, energy centres, and other integrated equipment, allowing large assemblies to be built and tested before transport rather than fabricated piecemeal at the final location.
The Irish interconnector project used that factory model to compress design, manufacture, testing, transport, and commissioning into a schedule driven by the planned increase in network capacity. The equipment has now moved beyond the delivery phase; the operational measure is whether the integrated 15.5MW system continues to hold the required outlet temperature as gas flows move towards the higher 6.9-million-standard-cubic-metre daily capacity.
