asked the Secretary of State for the Home Department why the specification for shelters set out in "Domestic Nuclear Shelters: Technical Guidance" does not provide for withstanding blast overpressures in excess of 1·5 lb. per square inch in view of the fact that such pressures would be widely exceeded in the event of a nuclear explosion.
The blast protection provided by each of the four types of shelter is stated in the table on page 18 of the publication. It ranges from 1·5 lb. per square inch to over 11 lb. per square inch.The overpressure resulting from a nuclear explosion decreases with distance from it, and the table indicates the distance at which each type of shelter would provide adequate protection from a 1 megaton air burst weapon.