New standards can boost offsite uptake

Using common standards across all offsite products can help the sector thrive, argue the authors of a new BSI report, Chris Goodier, Nigel Fraser, Clare Price and Anna Fricker.

Adoption of offsite manufacturing could be increased through purpose-designed standards, along with a more collaborative approach across the construction industry.

Those are the findings of The Role of Standards in Offsite Construction, a report by the British Standards Institution (BSI), undertaken by Loughborough University.

The study follows last year's House of Lords inquiry into offsite's potential benefits and challenges, which concluded that "the government should promote the adoption of recognised standards for offsite manufactured components by working with bodies such as BSI".

The research, which sought to assess the relevance, usability, completeness and level of consensus across current offsite standards, involved interviews and workshops across the main material sectors of precast concrete, steel and timber, including supply, design and construction communities.

The research identified several common challenges, including that contractors and suppliers were often working to different tolerances in offsite construction.

In some instances these tolerances were out of date and at other times manufacturers, contractors and installers were developing, but not necessarily communicating, their own tolerances. As a result, challenges were often encountered during installation and assembly.

New standards could help alleviate these challenges by ensuring all parties work to the same or suitable tolerances. BIM could facilitate this type of collaboration by making early contractor involvement easier.

The connections between offsite elements and interfaces could also benefit from increased standardisation. Currently, common materials sourced from different suppliers do not necessarily share common connections, with structural interfaces also posing similar connection challenges. Standardising connections for materials and interfaces has the potential to reduce challenges at the construction and installation stage, particularly if a holistic approach is taken.

This would involve standardisation across manufacturers, interfaces and connections between different materials, for example steel to timber, and could be facilitated by prototyping.

By taking a pan-sector approach, offsite's benefits could extend across a wide range of construction projects, beyond housing. For example, a single floor interface specification in a bathroom pod could apply equally to student accommodation, a hospital or an airport. This "platform" approach is gaining significant traction, with the Infrastructure & Projects Authority running a call for evidence which closed in February.

By creating common standards across tolerances and interfaces, knowledge may be better shared across the offsite sector, leading to improved build quality and fewer assembly challenges.

The challenge remains that far more information is expected from offsite suppliers than for most other sectors in construction. This deters transparency, to protect intellectual property, and needs to be addressed so the potential benefits of knowledge-sharing can be realised.

But there are movements towards shared definitions, including BuildOffsite's glossary for terminology and the government's definition framework.

A major task ahead is creating robust and user-friendly standards that are specific to, or suitably address, offsite products.

The Role of Standards in Offsite Construction highlights the opportunities for standardisation. The offsite sector can take great steps forward if it supports and engages with BSI in the development of new and existing standards, ensuring they are fit for purpose, user-friendly and help the sector expand and develop.

Chris Goodier is director at Loughborough University's Centre for Innovative and Collaborative Construction Engineering. Nigel Fraser is director at West One Management Consulting. Clare Price is market development manager, and Anna Fricker is programme manager, at BSI.