GAS MASKS.

Auckland Star, Volume LXXI, Issue 172, 22 July 1940, Page 6

GAS MASKS.

N.S.W. PRECAUTIONS. COVERING FOR BLACK-OUTS. RUBBISH REMOVAL URGED. (Special—By Air Man.) SYDNEY, July 17.' Gas masks will soon be made available to Sydney residents at cost price under a scheme which has been launched by a committee that includes three doctors. A £35,000 plant will mass produce the masks. The project is being conducted under the title of Community Gas Masks Association. To provide initial finance it is proposed to charge a membership fee of £1, which will include the supply of one mask. A rebate equal to the difference between the membership fee and the actual production cost will be made to members later when manufacturing has been established on a large scale.

The National Emergency Services, the N.S.W. equivalent of A.K.P., is also considering standard equipment to cover windows for black-out and bomb splinter protection purposes, and the best type of shovel with which to handle an incendiary bomb. The experts have not jet decided whether a steel shovel or a heavy long-handled wooden shovel is best. It has been discovered that some Australian hardwoods have a remarkable resistance to fire.

In a lecture to 400 special wardens at Sydney Town Hall the Government technical adviser on A.H.P., Mr. Brooksbank, gave the following information as to the types of bombs which might be used in the event of an air raid on Sydney. He said a gas bomb would 'burst on the roofs or top. floor of a building. A fragmentation bomb would burst on the roof and a tire bomb would burst beween the slates of the roof and the ceiling. A demolition bomb with delayed action fuse would go through all floors and burst in the basement. In 1935, Mr. Brooksbank said, th'ere was not one building in Australia that could withstand a demolition bomb. For absolute protection 15 feet of concrete or 60 feet of earth was required, and this was not a commercial proposition. People, he said, would be safest on middle floors and in the middle of the building. Detecting 'Planes.

The modern method of air raid attacks on coastal cities was for bombers to glide in silently from the sea. Predictor instruments could detect 'planes, with their engines cut off, up to 50 miles away, but people employed at noisy machines or typewriters would not hear external warning signals. The best type of internal warning signal was the ordinary electric bell used with a definite code of rings. Mr. Brooksbank urged that to minimise fire risk there should be a big drive to remove rubbish from buildings. He said that 40,000 tons of litter had been cleared away in six months in a campaign in Hamburg.

In another lecture next day, at the Town Hall, to 500 special wardens for city buildings, Mr. Brooksbank gave some further details of bombs and their effects. He said the power of high explosive bombs had almost reached the limit of scientific possibilities, but incendiary bombs were a long way from perfection. The high explosive fragmentation bomb, with a fuse so sensitive that it exploded on impact with a telephone wire or the twig of a tree, burst into 5000 pieces with a velocity greater than that of sound, so that no one ever heard the bomb that killed them. The blast effect created a local cyclone of 4500 m.p.h., compared with the natural cyclone of 80 m.p.h. The lungs of a human being in the blast area could not withstand this pressure. Sudden death without external injury occurred. A 5001b high explosive bomb had a lethal range of 50 feet in an open space, but in a narrow street the range might extend for a quarter of a mile each way. Flames arising from the bursting of a high explosive bomb were nearly always put out by the suction effect that followed the blast. It was this suction effect which caused the walls of buildings to fall outwards. Handling of Fire Bombs.

Mr. Brooksbank said fire bombs could be easily handled with sand, but on no account must water be used or it would explode in all directions, causing injury and additional fire*. The shovel with which a fire bomb was handled must have sand on it, for otherwise a bomb would burn through an ordinary iron shovel in two seconds. The average weight of a thermite electron bomb was just over 21b. Such a bomb generated a temperature of 5000 degrees for about 20 minutes.

As an instance of the technical care necessary in A.R.P. work, Mr. Brooksbank mentioned that beach sand was no use for fighting bombs because it contained salt, which absorbed moisture from the air.