Reinforced Autoclaved Aerated Concrete Surveys

Reinforced autoclaved aerated concrete (RAAC) is a lightweight construction material that was used in the construction of some public buildings between the 1950s and 1990s. It was mostly used in flat roofing. Despite its name, it is very different to traditional concrete. It is aerated, or ‘bubbly’, and is therefore less durable than traditional concrete.

RAAC can be susceptible to failure when exposed to moisture. As a result, the UK Government has issued guidance to organisations across the UK to carry out building checks where RAAC may have been used.
A desktop ‘assessment on likelihood’ of the presence of RAAC is the first step in the process of assurance. The criteria for the survey were as follows;

• Year of building construction.
• Form of construction (where known).
• Presence of any concrete looking material.
• Presence of flat roofs.
• Presence of low-pitched roofs.

As part of that work, NHS Assure identified three sites within the Scottish Ambulance Service Estate for further survey. It is important to remember that these risk assessments are based on the desktop exercise using criteria listed above. They do not confirm the presence of RAAC. The three were:

• Falkirk Ambulance Station
• Castle Douglas Ambulance Station
• Dundee Site (Ambulance Station, Workshop, DHQ & Training Facility)

The Scottish Ambulance Service has now submitted a further 19 areas/sites to NHS Assure for a desk top review. We await their categorisation in terms of likelihood of RAAC. This work is precautionary, not the result of known issues on these sites nor indicative of any immediate threat.

The next stage of the process will be for any required discovery surveys to be undertaken by a contractor appointed by NHS Assure to confirm or rule out the presence of RAAC.

This is a national process, and we await the scheduling of the surveys to be carried out. The output of these surveys will provide further information on any recommended remedial actions.