Ronan Point

Last updated

Ronan Point
Ronan Point collapse closeup.jpg
Ronan Point, following the gas explosion
Ronan Point
General information
StatusDemolished
TypeTower block
LocationCanning Town
Town or cityLondon
Coordinates 51°30′46″N0°01′17″E / 51.5129°N 0.0215°E / 51.5129; 0.0215
Construction started1966
Completed1968
Demolished1986
Owner Newham Council
Technical details
Structural system Large panel system
MaterialPrefabricated pre-cast concrete
Floor count22
Design and construction
Main contractor Taylor Woodrow Anglian
Known forPartial collapse following gas explosion

Ronan Point was a 22-storey tower block in Canning Town in Newham, East London, that partially collapsed on 16 May 1968, only two months after it opened. A gas explosion blew out some load-bearing walls, causing the collapse of one entire corner of the building; four people died and 17 were injured. The nature of the failure (caused by both poor design and poor construction) led to a loss of public confidence in high-rise residential buildings, and major changes in British building regulations resulted.

Contents

Construction

Ronan Point was part of the wave of tower blocks built in the 1960s as cheap, affordable prefabricated housing for inhabitants of West Ham and other areas of London. The building was named after Deputy Mayor Harry Ronan, former chairman of London Borough of Newham's Housing Committee. The tower was built by Taylor Woodrow Anglian [1] using the large panel system building technology, which involves casting large concrete sections off-site and bolting them together to construct the building. The precast system used was the Danish Larsen & Nielsen system. [2] [3]

Construction started in 1966 and was completed on 11 March 1968. [4]

Collapse

At approximately 5:45 am on 16 May 1968, resident Ivy Hodge went into her kitchen in flat 90, a corner flat on the 18th floor of the building, and lit a match to light the gas stove for a cup of tea. [5] The match sparked a gas explosion that blew out the load-bearing flank wall, which had been supporting the four flats above. The flank wall fell away, leaving the floors above Hodge's living room and bedroom unsupported, causing their collapse. Falling floor slabs from Hodge's floor and the floors above pancaked down onto the floors below, causing a progressive collapse of all of the floors of the living room portions of the south-east units of the building. [6]

The building had just opened, and three of the four flats immediately above Hodge's were unoccupied. Four of the 260 residents died immediately and seventeen were injured, including a young mother who was stranded on a narrow ledge when the rest of her living room disappeared. Hodge survived, having been knocked unconscious in her kitchen by the blast. Leaking gas had collected in the hallway outside her kitchen, and the largest area of overpressure from the gas explosion's blast wave occurred at this concentration of gas in the hallway, causing the highest pressures of the blast wave to travel outward to the exterior flank wall uninterrupted. The existing overpressure in the kitchen as a result of the gas explosion's origin there blunted the higher overpressure caused by the hallway explosion, leaving the walls of the kitchen intact and sparing Hodge's life. Also surviving the blast was Hodge's gas stove, which she took to her new address.

The gas leak was determined to have been caused by a cracked nut connecting the building's gas line to Hodge's stove, which was believed to have cracked due to being overtightened at the time of installation. The force of the blast also had lifted upward a portion of the ceiling in Hodge's unit (i.e., the unit above's floor slab) causing loss of the gravity load between the floor slab and flank wall necessary to keep the flank wall anchored to the floor slab. Further, a subsequent investigation determined that mechanical elements of the floor slab/flank wall connection were not properly designed to account for the effects of gravity load changes due to lateral forces such as high winds or explosions. [5]

Griffiths inquiry

In the immediate aftermath of the collapse, the government commissioned an inquiry, led by Hugh Griffiths, QC. It reported on dangers caused by pressure on the walls from explosion, wind, or fire, finding that although the design had complied with the current regulations, the following recommendations should be implemented: [7]

Rebuilding and later demolition

Ronan Point was partly rebuilt after the explosion, using strengthened joints designed to deal with those issues, and the building regulations were altered to ensure that similar designs would not be permitted in the future. However, public confidence in the safety of residential tower blocks was irreparably shaken, [8] and the public scepticism of Ronan Point was later found to be appropriate. [9]

Sam Webb, an architect who had given evidence to the Griffiths inquiry, predicted that after approximately 15 years, Ronan Point would develop structural problems and collapse. [10] Webb's concerns eventually led the council to evacuate the building, and then to demolish it in 1986 in a piecemeal manner (rather than, for example, using explosives). When this was done, the extent of the defects found shocked even some of the activists, including Webb himself. It was discovered that most of the mechanical connections between floor slabs and flank walls had not been attached properly during construction. On the lower floors, cracks were found in the concrete where it had been point-loaded, and it was alleged that the extra pressure on those points during a high wind (such as during the Great Storm of 1987, barely a year after the demolition) would soon have led to building collapse. [9]

Effect on legislation

The partial collapse of Ronan Point led to major changes in building regulations. The first of these came with the 5th Amendment to the Building Regulations in 1970. These are now embodied in Part A of the Building Regulations and cover "Disproportionate Collapse". They require that "the building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause". They specifically cover pressures which may be caused for example by wind forces, explosions (either internal or external), or vehicle incursions, and note that seismic design may occasionally be required. [11]

Immediately after the publication of the report the Government brought out interim measures to ensure the safety and integrity of buildings in the event of an explosion. All new buildings of over five storeys constructed after November 1968 were required to be able to resist an explosive force of 34  kPa (4.9  psi ). Existing buildings were allowed to resist an explosive force of 17 kPa (2.5 psi), provided that the gas supply was removed and flats were refitted for electric cooking and heating. [12]

Many other jurisdictions, including the US, have since amended their building codes to require that buildings subject to explosions or other accidents will not collapse to an extent disproportionate to the cause. [9]

Two days after the Grenfell Tower fire in 2017, John Knapton, emeritus professor of structural engineering at Newcastle University, claimed that regulations which came into force in 1971, following lessons learned from Ronan Point, had improved building structural strength in such a way as to prevent the collapse of the Grenfell Tower, which was built in 1974. [13]

Effect on housing

In 1985, the Building Research Establishment published a report entitled "The Structure of Ronan Point and other Taylor Woodrow – Anglian buildings" to advise local councils and building owners on checking the structural stability of their blocks. [14] Southwark Council confirmed in 2017 that strengthening work ordered after Ronan Point may not have been carried out on the Ledbury Estate, after structural weaknesses were found that led to the evacuation of four tower blocks. [15]

Within a couple of decades of the collapse of Ronan Point, the public's lack of confidence in the construction technique used at Ronan Point, together with the social problems within such developments, led to the demolition of many tower blocks. [8] In particular, the construction technique involved metal bolts which expand when they rust and crack the concrete around them. [16] In 2018, it was reported that two tower blocks on the Broadwater Farm estate in Tottenham, Tangmere House and Northholt House, were structurally unsound and could collapse catastrophically if there is a gas explosion or if a vehicle collides with the base. Both are to be evacuated urgently. Other buildings in Broadwater Farm had less serious problems. [17]

Legacy

In May 2018, 50 years after the partial collapse, Ronan Point was the subject of an experimental documentary film, And Then We Heard Shouts and Cries, by artist Ricky Chambers. Chambers' grandparents and mother had lived in flat 87 on the 18th floor of the tower block at the time of the gas explosion. [18] [19]

See also

Related Research Articles

<span class="mw-page-title-main">Tower block</span> Tall building; as opposed to a low-rise building

A tower block, high-rise, apartment tower, residential tower, apartment block, block of flats, or office tower is a tall building, as opposed to a low-rise building and is defined differently in terms of height depending on the jurisdiction. It is used as a residential, office building, or other functions including hotel, retail, or with multiple purposes combined. Residential high-rise buildings are also known in some varieties of English, such as British English, as tower blocks and may be referred to as MDUs, standing for multi-dwelling units. A very tall high-rise building is referred to as a skyscraper.

<span class="mw-page-title-main">Blast injury</span> Type of physical trauma

A blast injury is a complex type of physical trauma resulting from direct or indirect exposure to an explosion. Blast injuries occur with the detonation of high-order explosives as well as the deflagration of low order explosives. These injuries are compounded when the explosion occurs in a confined space.

<span class="mw-page-title-main">Blast shelter</span> Place where people can go to protect themselves from blasts and explosions

A blast shelter is a place where people can go to protect themselves from blasts and explosions, like those from bombs, or in hazardous worksites, such as on oil and gas refineries or petrochemical facilities. It differs from a fallout shelter, in that its main purpose is to protect from shock waves and overpressure instead of from radioactive precipitation, as a fallout shelter does. It is also possible for a shelter to protect from both blasts and fallout.

<span class="mw-page-title-main">Gas explosion</span> Explosion caused by mixing a combustible gas with air in the presence of an ignition source

A gas explosion is the ignition of a mixture of air and flammable gas, typically from a gas leak. In household accidents, the principal explosive gases are those used for heating or cooking purposes such as natural gas, methane, propane, butane. In industrial explosions many other gases, like hydrogen, as well as evaporated (gaseous) gasoline or ethanol play an important role. Industrial gas explosions can be prevented with the use of intrinsic safety barriers to prevent ignition, or use of alternative energy.

<span class="mw-page-title-main">Broadwater Farm</span> Human settlement in England

Broadwater Farm, often referred to simply as "The Farm", is an area in Tottenham, North London, straddling the River Moselle. The eastern half of the area is dominated by the Broadwater Farm Estate ("BWFE"), an experiment in high-density social housing, loosely based on Corbusian ideas, dominated by concrete towers connected by walkways, built in the late 1960s using cheap but fire-vulnerable pre-fabricated concrete panels. The western half of the area is taken up by Lordship Recreation Ground, one of north London's largest parks. Broadwater Farm in 2011 had a population of 4,844. The estate is owned by Haringey London Borough Council.

Building regulations in the United Kingdom are statutory instruments or statutory regulations that seek to ensure that the policies set out in the relevant legislation are carried out. Building regulations approval is required for most building work in the UK.

<span class="mw-page-title-main">Red Road Flats</span> Former high-rise housing complex in Glasgow, Scotland

The Red Road Flats were a mid-twentieth-century high-rise housing complex located between the districts of Balornock and Barmulloch in the northeast of the city of Glasgow, Scotland. The estate originally consisted of eight multi-storey blocks of steel frame construction. All were demolished by 2015. Two were "slabs", much wider in cross-section than they are deep. Six were "points", more of a traditional tower block shape. The slabs had 28 floors, the point blocks 31, and taken together, they were designed for a population of 4,700 people. The point blocks were among the tallest buildings in Glasgow at 89 metres (292 ft), second in overall height behind the former Bluevale and Whitevale Towers in Camlachie. The 30th floor of the point blocks were the highest inhabitable floor level of any building in Glasgow.

The Lakanal House fire occurred in a tower block on 3 July 2009 in Camberwell, London. Six people were killed, and at least 20 injured, when a high-rise fire, caused by a faulty television set, developed and spread through a number of flats in the twelve-storey building.

<span class="mw-page-title-main">Sampoong Department Store collapse</span> 1995 building collapse in Seoul, South Korea

On June 29, 1995, the Sampoong Department Store in Seoul, South Korea, collapsed due to a structural failure. The collapse killed 502 people and injured 937, making it the largest peacetime disaster in South Korean history. It was the deadliest non-deliberate modern building collapse until the 2013 Rana Plaza factory collapse in Bangladesh.

<span class="mw-page-title-main">Structural integrity and failure</span> Ability of a structure to support a designed structural load without breaking

Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load without breaking and includes the study of past structural failures in order to prevent failures in future designs.

Robustness is the ability of a structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause – as defined in EN 1991-1-7 of the Accidental Actions Eurocode.

<span class="mw-page-title-main">Grenfell Tower fire</span> 2017 fire in West London

On 14 June 2017, a high-rise fire broke out in the 24-storey Grenfell Tower block of flats in North Kensington, West London, England, at 00:54 BST and burned for 60 hours. Seventy people died at the scene and two people died later in hospital, with more than 70 injured and 223 escaping. It was the deadliest structural fire in the United Kingdom since the 1988 Piper Alpha oil-platform disaster and the worst UK residential fire since the Blitz of World War II.

<span class="mw-page-title-main">Grenfell Tower</span> Residential building in London ravaged by fire in 2017

Grenfell Tower is a derelict 24-storey residential tower block in North Kensington in London, England. The tower was completed in 1974 as part of the first phase of the Lancaster West Estate. Most of the tower was destroyed in a severe fire on 14 June 2017.

Samuel Webb was a British architect who was famous for his work on the structural and fire safety of Tower Blocks following his investigation into the Ronan Point tower block.

<span class="mw-page-title-main">Tower blocks in Great Britain</span> High-rise buildings for residential use

Tower blocks are high-rise buildings for residential use. These blocks began to be built in Great Britain after the Second World War. The first residential tower block, "The Lawn", was constructed in Harlow, Essex, in 1951; it is now a Grade II listed building. In many cases, tower blocks were seen as a "quick-fix" to cure problems caused by the existence of crumbling and unsanitary 19th-century dwellings or to replace buildings destroyed by German aerial bombing. It was argued that towers surrounded by public open space could provide for the same population density as the terraced housing and small private gardens they replaced, offering larger rooms and improved views, whilst being cheaper to build.

<span class="mw-page-title-main">Harrow Court fire</span>

The Harrow Court fire occurred in a tower block on 2 February 2005 in Stevenage, Hertfordshire, England. Three people were killed, two of them firefighters, when a fire developed and spread from the 14th floor. An investigation of the fire found that there was an Abnormal Rapid Fire Development, caused by a candle melting the surface of a television, which then spread rapidly up the outside of the building to subsequent floors.

<span class="mw-page-title-main">Ledbury Estate</span> Housing estate in Peckham, London

The Ledbury Estate is a large estate of social housing, in Peckham in the London Borough of Southwark. The estate is just south of the Old Kent Road, part of the A2 4 kilometres (2.5 mi) from both Tower Bridge and the Elephant & Castle it is adjacent to land used by George Livesey for the South London Gasworks.

<span class="mw-page-title-main">2018 Magnitogorsk building collapse</span> 2018 apartment building collapse in Magnitogorsk, Chelyabinsk Oblast, Russia

On 31 December 2018, at approximately 6:02 a.m. local time, an apartment block in Magnitogorsk, Chelyabinsk Oblast, Russia, partially collapsed. The collapse killed 39 people and injured 17 more. The cause of the collapse is believed to have been a gas explosion.

<span class="mw-page-title-main">United Kingdom cladding crisis</span> Building material flammability issue

The United Kingdom cladding crisis, also known as the cladding scandal, is an ongoing social crisis that followed the Grenfell Tower fire of 14 June 2017 and the Bolton Cube fire of 15 November 2019. The fires revealed that large numbers of buildings had been clad in dangerously combustible materials, comprising a combination of flammable cladding and/or flammable insulation.

<span class="mw-page-title-main">Barton House, Bristol</span> Residential building in Bristol, England

Barton House is a residential tower block in the Barton Hill area of Bristol, England. It is the city's oldest tower block and was officially opened on 23 July 1958.

References

  1. "1968: Three die as tower block collapses". BBC. 16 May 1968. Retrieved 16 June 2016.
  2. Practical Building Conservation: Concrete. English Heritage. 2013. p. 320. ISBN   978-0-7546-4565-8.
  3. "Failure of a High-Rise System" . Retrieved 23 January 2015.
  4. "The collapse of Ronan Point, 1968 - in pictures". The Guardian. 16 May 2018. Retrieved 12 July 2018.
  5. 1 2 Wearne, Phillip (1999). Collapse: Why Buildings Fall Down.
  6. "The Ronan Point Collapse". Logic4training. 16 May 2014.
  7. Griffiths, H. (1968). "Report of the inquiry into the collapse of flats at Ronan Point, Canning Town". HMSO. pp. 62–64. Retrieved 14 June 2022.
  8. 1 2 "Ronan Point" . Retrieved 31 October 2014.
  9. 1 2 3 Beyond Failure: Forensic Case Studies for Civil Engineers. Reston, Virginia, USA: American Society of Civil Engineers Publications. 2009. p. 418. ISBN   978-0-7844-0973-2.
  10. Pearson, Cynthia; Delatte, Norbert (2005). "Ronan Point Apartment Tower Collapse and its Effect on Building Codes". Journal of Performance of Constructed Facilities. pp. 172–177. Retrieved 14 June 2022.
  11. "Approved Document A - Structure (2004 Edition incorporating 2010 and 2013 amendments)" (PDF). The Building Regulations 2010 (reprint ed.). HM Government. September 2013. Retrieved 3 March 2014.
  12. "One man's battle to improve tower block safety". Inside Housing. 15 May 2018. Retrieved 14 June 2022.
  13. "Grenfell Tower would have collapsed if built four years earlier, says expert". Daily Telegraph. 14 June 2017. Retrieved 16 June 2017.
  14. "Ledbury Estate: Structural Robustness Assessment for Large Panel System Tower Blocks with Piped Gas". Building. Southwick Council. 30 August 2017. p. 3. Retrieved 14 June 2022.
  15. "South London estate to be evacuated over safety fears - BBC News". BBC Online . 10 August 2017. Retrieved 10 August 2017.
  16. "Ronan Point: a fifty-year building safety problem". BBC News . 15 June 2018. Retrieved 2 April 2020.
  17. "Two Tottenham housing blocks at risk of catastrophic collapse". The Guardian . 20 June 2018. Retrieved 2 April 2020.
  18. Paget, Antonia (19 May 2018). "Tower explosion 50 years before Grenfell - but 'scandal must not be forgotten'". mirror.
  19. "Watch a new film about Ronan Point". Inside Housing.

Bibliography

A number of books have covered the collapse of Ronan Point, including Collapse: Why Buildings Fall Down by Phil Wearne ISBN   0-7522-1817-4. This was written to accompany the television series of the same name shown on Channel 4 in early 2000.

Building Research Establishment reports: