Offsite prefabrication: the safest heating solution?

10th June 2020

As we emerge from lockdown, offsite prefabricated bespoke heating solutions could hold the key to safer, faster high-quality boiler installation, suggests Tom Murray, Specification Director for Baxi Heating

During the COVID-19 crisis, the critical role of heating systems in keeping our essential buildings – our hospitals, schools, supermarkets and care homes –functioning safely has been abundantly clear.

In the last few months, the heating sector has stepped up admirably to the challenges brought by the pandemic, collaboratively adapting working practices with innovative, responsive solutions to restore heating in essential buildings.

Now a staged release of lockdown has begun and finally, our industry can plan a return to the list of heating projects that were abruptly put on hold. Faced with a backlog of heating refurbishments and restrictive working conditions, consultants, contractors and manufacturers will again be forced to improvise to arrive at effective new ways of working in the weeks and months ahead.

Prefabrication benefits

Fortunately, techniques and opportunities are available now that will meet all safety guidelines while facilitating swifter working methods. Use of prefabricated heating equipment is one such option.
Offsite manufacture is, of course, an established approach in the construction industry. In a survey by legal firm Clyde and Co, two-thirds of the top 50 construction firms questioned anticipated doubling the amount of work carried out offsite to improve efficiency, reduce costs, tackle the skills shortage and overcome technical challenges.

With reports of 30% cost and time savings1 , tighter quality control and reduced waste, there are clearly big gains to be made from this process.

When it comes to heating, it’s a method that is proven to deliver significant quality and time-saving benefits in new and existing buildings alike.

Carrying out most of the manufacturing offsite, using specialist machinery in a quality-controlled factory environment, reduces waste and leads to better build quality through improved control procedures.

As such, use of offsite prefabricated heating equipment enables safety requirements to be more easily met and policed so that health and safety remain a top priority from start to finish.

A case in point

Take the offsite boiler rig, a turnkey solution designed to facilitate multiple boiler installations. Unlike the inflexible, site-assembled cascade solutions offered by many manufacturers, the offsite rig can require zero onsite fabrication and be tailored to individual site needs. With hot works reduced and installers needing to spend less time on site, and in smaller numbers, this meets the goal for improved site safety.

A prefabricated bespoke heating solution like this reduces installation and commissioning to days rather than weeks, enabling boiler installations and replacements to be completed rapidly, safely and to the highest of standards.

Add to this the improved ease of scheduling and the ability to complete more projects safely and faster, and there’s a compelling argument for contractors to move to offsite fabrication.

Rapid turnkey solution

Let’s take a closer look at the bespoke rig solution. Effectively, it is a mini plant room system, complete with a bespoke configuration of boilers, pumps, controls, a dosing pot and a pressurisation unit. Remeha, for example, offers bespoke-designed, prefabricated solutions for both wall-hung and floor-standing boiler models. There’s even the option to include a combination of the two, if required.

A low loss header or plate heat exchanger, sized specifically for site requirements, can be integrated into the design to achieve hydraulic separation. The rig can additionally integrate project-specific controls such as weather compensation, sequencing or building management system direct operation to maximise seasonal efficiency and lower running costs. These can be pre-wired into a rig-mounted control panel for further onsite time savings.

The ability to configure the boilers bespoke to each project means that all site or project requirements can be factored in from the outset. This successfully avoids time-consuming snags while ensuring a quality installation. 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, making connection to the system both straightforward and rapid.

Each boiler module can be designed using BIM tools and 3D computer-aided design (CAD) systems for early visualisation. The drawings then form part of a comprehensive operations and maintenance documentation manual, part of the building’s ‘golden thread’ of information, for simpler future servicing and replacement.

Only once the design is clearly identified does production take place in a factory environment, with end-of-line testing providing added quality assurance.

The boilers are then delivered to site on a wheeled boiler frame with insulated pipework set. With the equipment coming from one supplier, only one delivery slot needs to be booked – a useful advantage where delivery restrictions apply.  


Offsite rigs are frequently specified on projects with tight timeframes such as school refurbishment projects.

At Queen Elizabeth’s Hospital School in Bristol, project M&E consultant Geoff Beaven selected replacement Gas 220 Ace floor-standing boilers “for their high efficiencies and reliability, and also for the offsite fabricated cascade options that would enable a faster, smoother installation. It was just what we needed, meeting all the project requirements and ensuring a speedy installation.”

Bridgemary School in Gosport is another example, where Ridge and Partners specified a prefabricated rig system using Quinta wall hung boilers to provide a time-saving solution to meet the project schedule. “The bespoke rig was great,” confirmed project contractor IDWe’s Paul Neve. “It was wheeled straight off the tail-lift and into place, saving us a lot of valuable time.”

Increased productivity

Selecting an offsite prefabricated solution like the bespoke rig also allows contractors to forge ahead with preparatory work during the production phase or complete other projects.

When replacing the existing boilers at its Gun Wharf offices, Medway Council opted to install Remeha Gas 220 Ace boilers on an offsite fabricated cascade arrangement to control the shutdown period. The design accommodated both the space constraints and the need for easy connection to the existing system, saving project contractor TSS Facilities onsite time and labour.

“While the pipework was being configured offsite, we were able to work on the system pipework, which sped up the installation process,” explained TSS Facilities’ Mark Basset. “Having the Gas 220 Ace boilers delivered in an offsite fabricated system made our lives so much easier. It allowed us to schedule the project and team more accurately, increasing our productivity. At the same time, it saved downtime and installation time.”

Bounce back

As we emerge from lockdown, protecting the health and wellbeing of their workforce will be the immediate priority for businesses and organisations. At the same time, due to the economic impact of the crisis, reducing building overheads where possible will be key. Added to this is the on-going drive to eliminate energy waste from heat in buildings as the UK strives to meet the 2050 net zero emissions target.

Ensuring that the heating system operates reliably and efficiently is central to achieving all of these goals. As specifiers and contractors respond to these requirements, prefabricated equipment like the bespoke rig will enable them to ramp up activity, achieve long-term high heating efficiency for their customers and boost their own productivity, all while ensure a safe working environment. In short, it offers a win-win opportunity for all.

Visit the Remeha website for more information

1. Rethinking Construction (The Egan Report) 1998    

This article first appeared in HVR Magazine