Some Wartime Experiences of British Gas Undertakings
H Townsend M.Inst.C.E – proceedings of the Institution of Gas Engineers 29th May 1919 pages 477-9.
This explosion occurred at about (3 52 p.m. on Friday Jan. 19th. 1917, and the shock experienced at the East Greenwich Gasworks was very severe causing No.2 Gasholder to be completely wrecked, and No.1 to be very seriously damaged; while large numbers of slates were torn from the roofs windows broken in all directions and the works generally severely shaken.
Before saying more about the No 2 Gasholder, which was the most serious damage sustained and the extent of which only became known upon close examination after the occurrence, it might be interesting to narrate the effect the explosion had upon the Works generally and upon those present at the time. At the offices of the works which are close to the riverside, an And some 700 yards away from the gasholder the report was terrific the floor appeared to heave the building rocked. This was followed by a blinding glare seen through the Venetian sunblinds, and lasting a very few seconds, during which it seemed to be as light as day outside. The glare ceased, and the northeastern sky was suffused with the glow of a tremendous fire.
The source of the shock and the report was once apparent. Those in charge immediately rushed to see whether any damage had been done to the carbonising plant more especially on the vacuum side of the exhauster. The boiler attendants and engine drivers, however, said that all was well with their plant but somebody said, “No.2 Gasholder has gone up.” It was evident however that a supply of gas was being maintained, for though some lights had been blown out, many were still burning.
The damage sustained by buildings was found to be practically confined to windows and doors. The windows of the offices engine rooms, and shops were extensively smashed, window frames were dislodged, and one or two heavy doors blown off their hinges. The floor of the engineer’s office was thickly strewn with small pieces of plate glass from end to end of a long narrow room, and a 4½ inch partition between it and the stores had been severely shaken. The roofs of buildings, apart from the stripping of slates which was not extensive, escaped uninjured, also the retort house shafts. No.7 coal store, however sustained some damage. Here the roof principals are carried on columns placed about 30 ft apart on the coal-store wall and the spaces between them are filled in with corrugated sheeting having a timber stiffener (3 in. by 4 in. by 16 in.) in the middle of each bay. Eleven of these, out of a total of fourteen, were broken.
With regard to No.2 Gasholder this was built in 1891, and had a working capacity of approximately 12 million cu.ft. when fully extended. The holder comprised six lifts of which the first and second were ‘flying lift? The outer lift being 300 ft. in diameter. The depth of the lift to the rest stones is 31 feet, and the rise of the crown is 25 ft., The stock of gas in this holder at 6 o’clock being only 7,865,000 cu.ft proves that the top lift was well within the guide-columns at the moment of the catastrophe. In other words, so far as the working conditions are concerned the holder, at the moment of the shock, was probably in the very best position to resist any unusual or special strain such as a gale of wind or drifting snow, provision for which had been foreseen and was duly provided against. The holder however had not been built to stand up against the shock of an explosion of a large quantity of T.N.T occurring at a distance of 1½ miles as the crow flies.
It would appear to be clear that the holder was wrecked either by the pressure produced in the atmosphere by the explosion or to the vacuum immediately succeeding it. That a tremendous shock resulted from the explosion is shown by the fact that windows and doors were blown outward or inwards many miles from the scene of the explosion and at the Old Kent Road Works which 5 some four miles distant as the Crow flies, a holder of 5½ million cu ft. capacity was seen to rise and fall from 1 ft. to 3 ft, according to the testimony of eye witnesses. The extent of this disturbance is borne out by the chart registering the distinct pressure, which oscillated between 46-10ths and 55-l0ths settling down to its normal pressure of 50-l0ths in the space of from five to eight minutes so far as can be ascertained by the state of the chart. It must be mentioned that the blinding glare which was observed throughout the whole of London at 6.52 pm. On that January evening, the lightness of which has been compared to that of a summer day, was undoubtedly due to the burning in a few seconds of 8 million cuft. of gas contained in this holder.
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