Driving efficiency through offsite solutions
Use of off-site fabrication is on the rise, providing specifiers, contractors and building operators with efficient, quality solutions to tackle common refurbishment restraints and meet tighter performance targets for heating and hot water provision. Tom Murray, Head of Specification at Baxi Commercial Solutions, outlines the benefits.
The drive to reduce heat-related energy consumption and emissions in commercial buildings continues apace. But providing an efficient, modern heating and hot water system can be far from straightforward in certain buildings.
Constrained existing plant room space, increasingly tight project schedules, access restrictions, skills shortages and, more recently, product availability challenges, are some of the frequent obstacles building services professionals experience on refurbishment projects. One effective and efficient solution is to use offsite fabrication.
Whether planning a complete plant room installation, a heating system refurbishment or a boiler replacement, prefabrication makes everything simpler. For specifiers and contractors, it offers compelling benefits including easier installation, reduced onsite time and labour, improved health and safety and enhanced quality assurance. The opportunity for off-site fabrication exists for the full range of applications, from the largest containerised plant rooms to single boiler systems within existing buildings.
How does the process work? Each prefabricated module is typically designed using BIM tools and 3D computer-aided design (CAD) modelling. This enables revisions to be made collectively while supporting best practice design, installation, operation, and maintenance.
The key is to plan ahead. Bringing key stakeholders together at the outset enables the project requirements and any limitations to be addressed in the design, along with any future plans. For example, if air source heat pumps are to be integrated into the next phase, this is the opportune moment to consider a prefabricated interface unit between the technologies or the exact siting of the heat pump. The planning process that is central to the success of offsite fabrication will also smooth the subsequent phases of the refurbishment programme.
Once the final design has been approved, production takes place in a quality-controlled factory environment. Thanks to the use of specialist machinery, improved control procedures and comprehensive end-of-line testing, the highest build quality can be achieved. Sustainability is a major driver for the building services industry and building operators alike, so it’s worth noting that offsite fabrication also has the potential to reduce waste, leading to a lower environmental impact.
How is the offsite technique applied? Prefabricated and preassembled modules can be purpose designed to provide a quality plug and play solution that delivers valuable time and space savings.
Take boiler installation projects. Bespoke boiler rig modules can be designed to make the best use of available space, whether within a small or hard-to-access basement plant room, in an energy centre or in a full roof-top packaged plant room. Manufactured offsite, the boilers are delivered to the site on a wheeled rig unit or in smaller modules, if required, for simple re-connection into a single frame inside the plant room.
On older heating systems, there is the option to integrate specially sized Plate Heat Exchangers (PHE) and air/dirt separators into the rig, with matched boiler pumps, to optimise the lifetime operation of the new boilers.
The rig can also be designed with integrated controls to maximise seasonal efficiency for lower running costs. Even the position and size of the system connections on the rig can be produced to match the existing system pipework in the plant room for easy connection.
How and where are offsite fabricated solutions used? One example is the bespoke rig system installed by social housing provider Wakefield and District Housing (WDH) to replace ageing boilers serving the district heating system at their Smirthwaite Estate in Yorkshire.
Improved energy efficiency, reduced downtime and minimal disruption were the key requirements. As renewable technologies were not a feasible option for this project, Rob Wilson, consultant at Building Services Solutions, specified installing eight high-efficiency boilers using a Remeha offsite fabricated cascade system with a PHE.
Close collaboration resulted in a customised rig with integrated boilers, insulated pipework set and pumps, a PHE, pressurisation unit, dosing pot and an expansion vessel.
This was an unusually large project for an in-house team, but the bespoke rig system provided a good structure for WDH’s engineers, avoiding the need to size the individual components and saving a significant amount of installation time.
It also resulted in a very well organised plant room that made the best use of space while providing good accessibility to all the boilers for straightforward future maintenance to maximise efficiency throughout the lifecycle of the equipment.
Refurbishing existing energy centre
A further example is the bespoke-designed packaged plant solution that is providing heat and power at Blackberry Hill, a landmark new development in Bristol.
The Grade II listed former hospital site has been transformed into an exciting residential scheme including retail and business spaces by Vistry Partnership working with Homes England, Bristol City Council and Sovereign Housing Association.
A Combined Heat and Power (CHP) and boiler system was selected to serve the four district heat circuits feeding the original building and the new additional blocks.
However, the very tight space within the plant room and the building’s listed status were major concerns on this project. Our packaged solutions team worked with Vistry Energy to design and produce tailor-made boiler skids with pump sets and fully insulated prefabricated pipework, using specialist equipment design to achieve the compact footprint that the project required.
The skids connect onto two prefabricated frames accommodating the pumps and high-level pipework. These fit against the walls, leaving sufficient space for the CHP and the two buffer vessels situated at the opposite end of the plant room.
Using a quality offsite-fabricated solution successfully overcame all the project limitations, turning what would have been an extremely challenging installation into a faster, easier and safer process.
Containerised plant rooms
Offsite fabrication also offers the opportunity to relocate the heating and hot water services.
Containerised packaged plant rooms are increasingly popular, particularly on projects where strict limitations apply as to when work can be carried out, such as schools.
Using a packaged solution means that there is one point of contact for the whole system. The one-stop-shop system integrates the heat source – any combination of boilers, CHP, air source heat pumps and gas-fired water heaters – with pumps, controls and accessories.
The benefit of this approach is that it hugely reduces the potential for delay, helping to keep the project on schedule and avoiding any last-minute hitches due to product availability. An added advantage for contractors and building operators is that it enables just-in-time delivery, removing the need to store equipment on site and simplifying site management.
The packaged plant room can be purpose-designed in sections or as a single lift, depending on the site requirements, to enable straightforward transportation, accurate positioning and easier installation.
Prefabricated, pre-tested, fitted and connected, it can be positioned quickly and safely to meet the fixed timeframe. What’s more, relocating the plant room frees up valuable space within the building, whether that’s a new teaching area, an extra hotel room, or new office space.
Benefits for all
Offsite fabrication and preassembly bring important benefits to building services professionals, facilities managers and estates managers, from enhanced quality, health and safety and compliance assurance to greater flexibility, increased efficiency and improved productivity.
As manufacturers and offsite specialists, we look forward to working with specifiers and contractors to provide them with efficient solutions to high performance heat that will support their customers in meeting their sustainability goals.
Tom Murray is Head of Specification at Baxi Commercial Solutions