page_title: Air raid shelter
section_title: Morrison shelter
hierarchical_section_title: Air raid shelter / World War II / United Kingdom / Morrison shelter
caption_attribution_description: English: A couple sleeping in a Morrison shelter during the Second World War. A Morrison shelter in use.
context_page_description: Air raid shelters, also known as bomb shelters, are structures for the protection of non-combatants as well as combatants against enemy attacks from the air. They are similar to bunkers in many regards, although they are not designed to defend against ground attack.
  Prior to World War II, in May 1924, an Air Raid Precautions Committee was set up in the United Kingdom. For years, little progress was made with shelters because of the apparently irreconcilable conflict between the need to send the public underground for shelter and the need to keep them above ground for protection against gas attacks. In February 1936 the Home Secretary appointed a technical Committee on Structural Precautions against Air Attack.
  By November 1937, there had only been slow progress, because of a serious lack of data on which to base any design recommendations and the Committee proposed that the Home Office should have its own department for research into structural precautions, rather than relying on research work done by the Bombing Test Committee to support the development of bomb design and strategy. This proposal was eventually implemented in January 1939.
context_section_description: Media related to Morrison shelter at Wikimedia Commons
  The Morrison shelter, officially termed Table (Morrison) Indoor Shelter, had a cage-like construction beneath it. It was designed by John Baker and named after Herbert Morrison, the Minister of Home Security at the time. It was the result of the realisation that due to the lack of house cellars it was necessary to develop an effective type of indoor shelter.
  The shelters came in assembly kits, to be bolted together inside the home. They were approximately 6 ft 6 in (2 m) long, 4 ft (1.2 m) wide and 2 ft 6 in (0.75 m) high, had a solid 1/8 in (3 mm) steel plate "table" top, welded wire mesh sides, and a metal lath "mattress"- type floor. Altogether it had 359 parts and had 3 tools supplied with the pack.
  The  shelter was provided free to households whose combined income was less than £400 per year (equivalent to £25,000 in 2019).
  When Head of the Engineering Department at Cambridge University, Professor John Baker (later Lord Baker) presented an undergraduate lecture on the principles of design of the shelter, as an interesting introduction to his theory of plastic design of structures and it can be summarised as follows:
  It was impractical to produce a design for mass production that could withstand a direct hit, and so it was a matter of selecting a suitable design target that would save lives in many cases of blast damage to bombed houses. Examination of bombed buildings indicated that in many instances, one end wall of a house was sucked or blown out by a nearby blast, and the floor of the first storey pivoted about its other end (supported by a largely intact wall) and killed the inhabitants. The Morrison shelter was therefore designed to be able to withstand the upper floor falling, of a typical two storey-house undergoing a partial collapse. The shelter was designed to absorb this energy by plastic deformation, since this can absorb two or three orders of magnitude more energy than elastic deformation.  Its design enabled the family to sleep under the shelter at night or during raids, and to use it as a dining table in the daytime, making it a practical item in the house.
  Half a million Morrison shelters had been distributed by the end of 1941, with a further 100,000 being added in 1943 to prepare the population for the expected German V-1 flying bomb (doodlebug) attacks.
  In one examination of 44 severely damaged houses it was found that three people had been killed, 13 seriously injured, and 16 slightly injured out of a total of 136 people who had occupied Morrison shelters; thus 120 out of 136 escaped from severely bomb-damaged houses without serious injury. Furthermore,  it was discovered that the fatalities had occurred in a house which had suffered a direct hit, and some of the severely injured were in shelters sited incorrectly within the houses.
  In July 1950 the Royal Commission on Awards to Inventors made an award of £3,000 (£104,000) to Baker for his design of the Morrison shelter.
caption: A couple demonstrating the use of a Morrison shelter
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