The effect of powerful bomb explosions is very destructive over a certain distance but moderate and minor damage occurs beyond this zone of heavy destruction. Following certain well-known principles of protection, which are discussed in this handout, could reduce these effects.
Principle of Protection
The important principle of protection is to interpose any thing which can neutralize the destructive effects of the bomb between point of explosion of the bomb and the object to be protected. To think in terms of absolute protection against the destructive effects of modern weapons is not a practical proposition. However it must be understood that it is possible to provide some degree of protection so as to minimize casualties and damage to a reasonable extent.
Methods of Protection
(i) Dispersions :
This reduces the congestion in the target area. The personnel, vital plants, stores etc. are dispersed in the target area in such a way that by a single bomb explosion, not more than one building, plant, store, shelter etc. is affected at a time. Even those who are on essential duty should not be allowed to live within 500 to 1000 yards radius of targets such as ammunition factories etc. Similarly shelter should not accommodate more than 50 persons at one place. Walls of adequate thickness to confirm this rule may divide the larger shelters.
(ii) Provision of Shelters for Individuals and Communities.
Beside providing for public shelters, the public has to be assisted in converting parts of their homes as "Strong Rooms" or "Refugee Rooms" which could be used as Shelters.
(iii) Training of general public:
This includes the general public showing an immediate, automatic and correct response to an air raid warning.
(a) The people must be trained in taking cover in the absence of a Shelter nearby.
(b) The general public must be trained in how to save themselves from glass splinters of their own house windows etc.
(c) Structural precaution and protection to vital plants and Essential Shelters. This includes strengthening of doors, walls or roofs of existing buildings and plants, incorporating additional protective walls or trenches against earth shake effects etc.
Standards of lateral and overhead protection: –
Near the point of explosion of a 500 lbs general-purpose bomb, the effects are very destructive. A number of persons would be injured or killed and damage to property would result in greater distances from the bomb explosion if they are not protected. Protection required at the point of explosion is very costly. A, 5 to 7 feet thick reinforced roof will be required to withstand a direct hit from 500 Lbs. GP bomb. Therefore the protection to be thought is from the blast splinters which fly along the ground. The thickness required to withstand the blast splinter effects of 500 lbs GP bomb at distance of about 50 feet is given below for some common material. The overhead protection aimed at is against the fall of debris raised up by bomb explosion and of anti-aircraft shell splinters, small incendiary bombs etc.