Reinforced Autoclaved Aerated Concrete (RAAC): Management subgroup minutes - 25 June 2024

Attendees and apologies

• Scottish Government
• NHS Scotland Assure
• Scottish Fire and Rescue Service (SFRS)
• Scottish Heads of Property Services (SHoPs)
• Institution of Structural Engineers (IStructE)
• Manufacturing Technology Centre (MTC)
• Health and Safety Executive (HSE)
• Scottish Futures Trust (SFT)
• Cabinet Office (CO)

Items and actions

Welcome

Attendees were welcomed to the 4th meeting of the RAAC Management Sub-group.

Minute of previous meeting, actions arising

The meeting approved the minutes of the previous meeting (24 April) with actions noted as being completed.

In following up issues raised in the previous meeting it was confirmed that IStructE and HSE were developing further risk-based guidance. It was also noted that work was ongoing in developing phase 2 of MTC's current research project, including progressing the strategic outline business case and identifying funding.

MTC playbook

Ahead of publication the content of the playbook was currently being reviewed in conjunction with IStructE with a view to publishing in August (later than originally intended). A summary of the contents was provided to the sub-group. Section 1 will provide an introduction to RAAC, information on key events and the reason why an industry wide standard approach was needed.

Section 2 will cover technical issues around manufacturing, common failure modes, background and methodologies to the research programme, research conclusions and plans for phase 2. The section also provided a number of case studies.

Section 3 sets out 'next steps' - the intention that the playbook could enable the industry to make informed decisions, in line with IStructE guidance, along with an emphasis on collaboration and sharing lessons learnt.

In subsequent discussion the following issues were raised:

• the first edition of the playbook might be published partially redacted pending further work - but should still be informative for stakeholders. A second edition would be dependent on additional funding
• a lot of interest/requests around Non Destructive Testing (NDT) from asset owners. Multiple NDT techniques were available - or being tested - and now needed to be done at scale across the industry
• NDT solutions included ultrasonics and ground penetrating radar to assess end-bearing overlap. These were commercially available and at modest cost. Further information was available in the playgroup
• Multiple requests for assistance but MTC only has a small team therefore an approach of training others to use the equipment is preferred and is an opportunity to expand use of knowledge of the technology
• noted that the playbook was quite technical in nature and therefore might not be accessible to all stakeholders, such as individual homeowners affected by RAAC - additional funding might enable the development of a revised version aimed at a wider audience

Action Point 4.1 - Share the March MTC slides with the sub-group

NHS Assure survey work update

The survey programme was nearly finished and through a number of revisits were required these should be complete by next month. NHS Scotland was developing its own guidance on RAAC management in conjunction with WSP and was also providing training for estate and facility staff to increase awareness of how to escalate when changes in the condition of RAAC are detected.

Information was provided on the three pilot point cloud surveys. The remit of these surveys was to narrow down the areas of risk where investigation hadn't been done. Initial feedback is that the surveys are giving information on the behaviour of RAAC over the entire span and helping identify common themes such as penetration through RAAC panels and water ingress. These surveys would act as a guide to follow up internal surveys focusing on certain areas and would in turn lead to assessment of whether future surveys needed to be on an annual or triannual basis.

The following points were noted:

• point clouds are essentially a topographical survey allowing an assessment of a cross section of a roof and, with the addition of thermal imagery, identifying any physical deflection of RAAC panels. This enables a targeted approach for further investigation on issues such as end bearings
• the process can provide a significant amount of detail identifying original penetrations, later changes, and if there is damage to the support
• the next phase is to incrementally reduce risk by targeting the main areas of risk

Action Point 4.2 - Share results/information from the point cloud surveys

Sector Update (by exception)

School estate

Scottish Futures Trust noted that numbers of affected schools has stabilised with no additions to the list. Work on removing or mitigating RAAC was being scheduled for the summer holidays after which a further snapshot of where school estates were would be provided. The number of schools with RAAC was reducing as roofs were replaced. While a small number would continue to require monitoring most estates were looking to remove RAAC or put in place additional support.

Housing

Attendees noted the ongoing work by the Scottish Housing Regulator regarding the extent of RAAC in social housing. The meeting also noted concerns about RAAC in privately owned homes, including Right to Buy properties.

There was a separate RAAC in Housing sib-group and the question of how resources and guidance developed by IStructE and MTC, such as the playbook, could help support homeowners might be something to consider further.

Any other business

No items were raised.

Date of next meeting

To be confirmed