Refurbishment of UK state school buildings: A strategy and framework for BIM-based Digital Twinning

As part of a national strategy to reduce carbon and greenhouse gas emissions from buildings, the UK government identified Building Information Modelling (BIM) as central to meeting these targets and it has been mandated in all public sector projects since April 2016. The increasing adoption of BIM across the UK’s AEC industry produced a critical mass that makes it an important backbone for achieving a digital built Britain in which digital twinning (DT) - using the CDBB’s ‘Gemini’ principles, would capture the synergies between physical assets and their virtual equivalents for adding sustainable value to projects. However, both BIM and DT suffer from an absence of a strategic approach to dealing with existing buildings. This research was aimed at investigating the role of BIM and Digital Twinning in the refurbishment of existing school buildings in the UK from the perspective of energy efficiency and the funding mechanisms made available for such carbon-reduction interventions. The nature of the subject matter necessitated the collection and analysis of qualitative data from experts and representatives of key stakeholder groups. Data was gathered from interviews with 16 participants as well as nine focus group participants, before being analysed, triangulated, and cross-referenced with existing knowledge and theories.

Findings reveal that existing buildings are challenging to refurbish from a carbon reduction perspective, but BIM could bring benefits to DT of existing buildings including: digitalisation of procurement via integration of building performance simulation (BPS) and building management systems (BMS); bridging the energy performance gap; use of 3D scanning to capture existing buildings especially in refurbishment projects (although this is presently costly and labour intensive, and could benefit from drone-based automation); as well as the use of a Soft Landings champion to ensure client’s interest are protected in the capital phase. Other factors that will influence how DT is implemented during refurbishment of buildings include: need to conserve cultural heritage of those historic buildings with protected status and inefficient envelopes; as well as the need to integrate previous learnings and concepts from the energy efficiency capabilities of Net Zero Energy Buildings (NZEBs). Specific NZEB technologies that should be assimilated into DT process, albeit with the integration of IoT sensors were explored.

The research concluded that real-time nature of DT would make static energy certifications (e.g. Display Energy Certificates) unnecessary as energy use is dynamic and transient. Professionals should assimilate peculiarities of DT into existing project management frameworks, e.g. RIBA Plan of Works. The ‘data’ used in DT (obtained from sensors) and not necessarily the ‘information’ (obtained from BIM) was argued to be a primary requirement for successful DT implementation. Various data types were subsequently identified as requisite or beneficial for DT implementation including those related to indoor environmental quality (IEQ) as well as building fabric and its electro-mechanical systems. The tools, equipment and skills for implementing DT were also explored, including: secure internet connectivity; artificial Intelligence (AI) to interpret data and make autonomous decisions; competent digital twinning manager; interconnection of sensors with BMS; Internet of things (IoT); and a baseline 3D model.

Data privacy/security was thought to be a concern for end users who are wary of how their personal data (e.g. from sensors and facial recognition from CCTV footage) may be used in DT process. Other barriers to DT implementation include: coordinating multiple data sources; cost implication for existing buildings which lack proper as-built data and O&M information; inconsistency in the firms/organisation handling future refurbishment; human resistance to digital change; absence of technical know-how for managing a DT-powered facility; as well as the constantly evolving structural and energy needs of existing buildings that makes establishing a permanent energy consumption plan difficult. A conceptual framework for DT implementation was developed and validated in the focus group and suggestions (e.g. integrating BSRIA standards with those of BIM; introducing a cost appraisal mechanism; as well as making it flexible for various building types) were incorporated into the final DT framework.