£40,000,000 DAMAGES

New Zealand Times, Volume L, Issue 11649, 13 October 1923, Page 12

£40,000,000 DAMAGES

SMOKE HAVOC IN BRITAIN EFFECT ON . PAINTWORK. The Government has just appointed l a committee to report on the liest methodc of preventing the serious damage to the stone work of public buildings and monuments, over oO per cent, of which is duo to black smoke. But in fact black smoke i has a most destructive effect on everything relating to buildings—for example, paint work; a very largo proportion of rhe national paint bill is due entirely to this cause (writes David Brownlie, in the “Daily News,” London). Paint consists essentially of finely ground insoluble inorganic pigments, largely “white lead,” inixM with a drying oil (boiled linseed oil), and diluted, or “thinned” with turpentine. The action of black smoke and the sulphur acids present in it on the thin film of paint is extremely rapid, causing discolouration, seriously diminishing the value of the paint as a protective covering, and destroying it from a decorative point of view. The action consists in the sulphuric acid present acting on the lead’ and forming lead sulphate, so that the paint is decomposed whilst the sulphuretted hydrogen, a normal constituent of smoke, also combines with the lead to form dark-coloured lead sulphide, thus ruining the colour. Certain paints are now made from, white oxide of titanium instead of lead, which is not discoloured by sulphur. The most elaborate experiments on the action of black smoke on paint were carried out a number of years ago in Pittsburg—no more smoky than ou:r own townb to-day—and it was proved that the action of smoke cost the inhabitants of this town 330,000 dollars a year more for painting than a town of similar size where the smoke nuisance was not excessive.

Thus, for example, in tile average American city, the period between the original painting and the first repainting of woodwork is five years, with subsequent repaintings every seven years. In Pittsburg, the better class buildings have to be painted every year, and practically every building ib painted onoe in three years. Some very interesting investigations on this point were also enrried out in Manchester, and it appears that this city, typical of our largo industrial towns—is' a paradise for painters. Under decent conditions, as regards the purity of atmosphere, outside paint work in Great Britain ought to last three years, but in Manchester it looks shabby in one year has t, bo

renewed every two yeaTS A very detailed survey showed that tile paint bill of Manchester is 25 per cent, to 50 per cent, more as compared with towns Eiko Harrogate, Buxton, mid Southport. T'he total damage due to black in Great Britain from all causes is at least £40,000,000 per annum.