16 May 2018
Fifty years ago, at about 5.45am on the morning of Thursday 16 May 1968, Miss Ivy Hodge went into the kitchen of her new 18th storey flat to make herself a cup of tea. She lit a match to light the gas stove, the gas leak exploded, and the side wall of the flat was blown out. This caused the whole of the corner of the apartment block to collapse, killing four people and injuring 17, including Miss Hodge.
It was a watershed moment. The flat was in a new housing development called Ronan Point, and the inquiry that followed led to significant changes in the Building Regulations for structural design which still stand today. The disaster shocked the public and changed the way that designers thought about and specified buildings – in the same way that the Grenfell Tower disaster is currently changing the way that we consider the fire risks associated with high-rise apartment blocks.
Ronan Point had been built as part of a government-backed project to increase the number of homes being completed. There was a skills shortage, so the government was pushing the use of offsite construction. Various systems had been imported from elsewhere in Europe. The flats at Ronan Point were built using a large panel system (LPS) which involved offsite production of large concrete panels which were then bolted together on site.
An inquiry into the disaster found that the main fault lay in the design and in the standards governing the design. The concrete panels were found to be well constructed, but the joints were not sufficient and were not well executed on site. The wind code did not consider the fact that the wind strength is greater for tall buildings – when it was published in 1952, very few tall buildings were being constructed. By 1967, when Ronan Point was adding to the record number of homes built that year (470,000), there were many. In the light of the explosion the Building Regulations were amended to address the possibility of both progressive collapse – the spreading of collapse from one part of structure to other areas initially undamaged – and ¬disproportionate collapse, where the consequence of an event is far greater than expected.
Since then, the UK’s Building Regulations have included design against disproportionate collapse – initially considering only the height of the building but now also the use. So just as much consideration of disproportionate collapse in required for a 4-storey hospital as for a 50-storey apartment block. All buildings in the UK are affected, whether they are constructed on or off site, and the Eurocodes also incorporate a requirement to design against disproportionate collapse.
The precast concrete industry in the UK assures that all connections between precast concrete elements are as well tied as they can be, so that it can be checked easily on site. All members of the British Precast Architectural and Structural Association are pleased to supply precast concrete residential solutions that meet all these requirements and the many others that constitute current Building Regulations, providing safe and secure housing solutions that meet the challenges of climate change, fire, flood and tempest.