The Springfield Gas Explosion—How It Was Caused
, Explosives and Inflammables, Massachusetts Department of Public Safety
Disaster Result of Leaking Purifying Box and Slow Action of Central Valve, Causing Accumulation of Gas—Great Damage to Property
AN explosion occurred in the gas purifying plant of the Springfield, Mass., Gas Light Company, of Elm, Water and Howard Street, at 1 :10 P. M., February 1. The explosion, the cause of which is very graphically described in the accompanying report by Mr. Wedger, resulted in the death of three men and the injuring of over a half a hundred persons. The injured were struck down over a wide area, in the city hall, the court house, office and bank buildings and residences. Within a radius of two miles persons were hurt, those in the near vicinity of the explosion by wreckage and those further away by broken glass, fallen ceilings or objects dislodged by the discharge. A section which was one of the worst sufferers was a poorer residential district where houses and flats ‘were made practically uninhabitable. Shattered windows, roofs that leaked and in some eases walls that collapsed with the concussion caused half a hundred families to vacate their homes. In the tall Campanile tower, the city hall and the auditorium, which are situated about one-fourth of a mile east of the scene of the explosion, there was hardly a window left intact. The same thing was true of Memorial Hall, more to the south, and the Springfield Institution of Savings was wrecked when the glass roof caved in. While the court house was shaken, it was less severely damaged. Main Street and the business thoroughfares looked much as though they had been under a bombardment. The fire department, headed by Chief W. H. Daggett, was soon on the spot and formed a cordon around the wreckage of the tank, concentrating their efforts to confining the fire to that part of the plant, in which they were successful. The loss was estimated at approximately $800,000.Many suits have elready been brought against the Gas Light Company by individuals and concerns. The following report was transmitted to Alfred F. Foote, commissioner of public safety of Massachusetts, by Mr. Wedger on February 5 and constitutes the latter’s conclusions after a careful investigation of the disaster:
Report of Chemist Walter L. Wedger
At 1:10 P. M., February 1, 1923, a terrific explosion, followed by a slight fire occurred at the works of the Springfield Gas Light Company, corner of State and Water Streets, Springfield, resulting in the death of three men, many persons injured and a very large amount of property destroyed.
The plant is located near the Connecticut River and is bounded on the North by Elm Street, on the East by Water Street, on the South by Howard Street, and on the West by the N. Y., N. H. & H. R. R. and the Connecticut River. It consists of several large buildings including a retort house, a purifying house, garage and gasometer.
Where the Explosion Occurred
The explosion occurred in the purifying house situated on the Southwest corner of State and Water Streets. This was a brick-walled building, two stories in height with a wooden roof, 69 ft. 9 inch on Water Street and approximately 90 ft. on State Street. The first story is approximately 8 ft. in height with a cement floor and from the second floor to the ridge pole of the roof is all open, a distance of some 42 feet.
There are two parts to the purifying house, separated by a passageway called a bridge which extends overhead from the retort building. The westerly end of the purifying house is equipped with filter boxes of a different construction from those located in the easterly end, the latter being of an older type.
Description of the Filter Boxes
The escape of gas occurred in filter box No. 3 situated in the easterly end of the building on the second floor. There are four of these filter IKIXCS in this end of the building each 30 ft. long. 25 ft. wide and 3 ft. deep. They are constructed of cast iron surrounded by water pockets 6 in. in width and 24 feet deep, cast integral with the main box. The cover of these boxes consists of heavy sheet iron formed with an apron which extends down into the water pocket on all sides forming a water seal for the gas. These covers are also fitted with clamps which permit them to be raised by excessive pressure of gas to a certain point, or until the clamp engages a stop on the end thereof. Further pressure of gas blows up through the water seal.
These boxes are partly filled with shavings coated with ferric oxide. The gas passes in at the bottom of the box, through the filter formed as above and into a space at the top underneath the moveable cover, from which it is conducted down through a perpendicular pipe out at the bottom and into the meter house.
In passing through the filter the gas is purified of its hydrogen sulphide content and ferric sulphide and ferrous sulphide are formed on the shavings, which gradually accumulate sufficient sulphur to become caked up in solid form. When this occurs the filter lias to be renewed, the time for renewal of a filter being shown by increased pressure of the gas in the boxes through which the gas has previously passed.
Central Valve or Distributor
These four filter boxes are connected down through the floor of the second story to a central valve or distributor, two large pipes, a flow and a return, leading to each box. The central valve to which all pipes lead, is a large, heavy iron structure revolving in front of the ends of the eight pipes with double ports and ground joints. To operate this valve the outside of the main drum is fitted with a rack and at one side is a pinion, the key to which projects above the floor in the filter room. It takes five men to operate this valve, four to turn it and one just below the floor to drop in the key at the desired port.
About 1:00 P.M., February 1, the men in charge of the filter room noticed a blow-out in the water seal of filter No. 3, which was caused by excessive pressure of gas in filter No. 4. An attempt was made to stop the escaping gas by playing a water hose into the water seal at the side of No. 3. Failing in this, an attempt was made to operate the central valve to shunt the escaping gas into another filter and although four men tried to move this valve with pipe levers on the ends of the key, the attempt was unsuccessful and additional help was sent for. In the meantime the gas caused those present in the purifying room to seek the doorway for air. When the additional help had arrived the valve had been moved a short distance when the explosion occurred.
At either side of the bridge separating the easterly and westerly ends of the purifying house there are electric elevators operated by direct current electric motors and rheostats housed in what is called a pent house located above the bridge and partly above the roof of the easterly end of the purifying house. The walls of the easterly end next to the bridge were of corrugated iron as were the walls of the pent house and there was a hole in the floor of the pent house fitted with a ladder through which access was gained thereto.
Gas Mixes with Air in Explosive Volume
I estimate that if all the water had been blown out of the seal to filter No. 3, it would be equal to the discharge of gas from a 20 inch diameter pipe or 16,000 cu. ft. per minute, and that approximately half the water was blown out permitting a discharge of gas at the rate of 8,000 cu. ft. per minute into the upper portion of the earterly end of the purifying house. This was fitted with nine ventilators at the highest point of the roof each 30 inches in diameter and 8 ft. on centres.
The gas manufactured at this part of the plant is coal gas of a specific gravity of 0.4 as compared to air 1.0. Being lighter than air, it immediately arose to the upper part of the purifying house, becoming mixed with air in explosive proportions, viz., from 10 per cent, of gas to 90 per cent, of air, to 28 per cent, of gas to 72 per cent, of air, where it became ignited.
The time which elapsed between the first blowing out of the water seal and the explosion is variously estimated from five to ten minutes. From this it will be seen that from 40,000 to 80,000 cu. ft. of gas had escaped and become mixed with air.
Arrangement of Electric Elevator Connections
As previously stated, the wall of the pent house separating the motors and other electric elevator apparatus from the great volume of explosive gas-air mixture was constructed of corrugated iron with riveted joints, laps claimed to be several corrugations. Likewise the wall separating the easterly end of the purifying house from the space occupied by the bridge, underneath the pent house, is of corrugated iron. The floor of the pent house is of concrete, but there is a manhole in it for access, as previously explained, and there were three ventilators in the roof of the pent house, each 36 inches in diameter without dampers. Through the corrugated iron wall of the pent house a horizontal shaft passed into the upper part of the purifying house. This is claimed to have been made tight by a felt stuffing box having a steel disc on each side to prevent a possible escape of gas reaching the direct current motors which are liable to generate electric sparks on the commutator brushes and an arc is liable to be created when the rheostat stops the elevator.
Wind Forces Gas Toward Elevator Pent House
According to the records of the U. S. Hospital at Springfield, the wind at the time of the explosion was from the Northwest, which would force the explosive gas-air mixture towards the pent house.
When the call for help came to operate the central valve and shut off the escaping gas, an employee stepped on the western elevator and went up to the filter floor of the purifying house. As he stopped the elevator, raised the gate and stepped off, the explosion occurred.
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Cause of the Springfield Gas Explosion
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Explosion Caused by Electric Spark from Elevator
In my opinion, the ignition of the gas-air mixture and the subsequent explosion was caused by an electric spark when the employee stopped the elevator and stepped off. This ignited the gas which had escaped through the corrugated iron partition of the pent house, went in through the window or up through the manhole.
There are two other possible causes. First, that the ignition of the gas may have been brought about by sparks front the pipe of a workman having caused his clothing to take fire. Second, that a match carried by a workman may have been dropped on the floor and accidentally ignited.
This gas will not ignite from a dull spark from a pipe, and if his pipe was in his pocket and set fire to his clothing, it must have smouldered there for some time before it broke out into flame which would be necessary to ignite the gas. The match theory is, of course, possible, although in my opinion, remote. Ordinary precautions would preclude the possibility of the presence of matches or lighted pipes where the fire hazard was always present. I cannot credit the theory that either of these men deliberately lighted a match to light his pipe in that gas-laden atmosphere where they admit they sought fresh air at the door while waiting for additional help to close the valve.
Purifying Boxes of Old Style Construction
The purifying boxes or filters in the easterly end of the purifying house were built in the year 1903, being 20 years old. The purifying boxes in the western end of the building are of a different type, of more modern style, where any escape of gas caused by excessive pressure would be relieved into ventilating ducts, which would deliver the escaped gas high up in the air and none of it would escape into the room. A statement has been made to me by the superintendent of the plant to the effect that this accident could never happen with the style of purifying boxes they have installed in the westerly end.
The company realized the danger of leakage of gas reaching the sparking commutators in the pent house through the corrugated iron partitions above referred to and took the precaution to lap the corrugated sheets several corrugations and to imbed the ends in cement, also to form a stuffing box around the shaft as it passed through the sheet iron.
Primary Cause of Disaster
The primary cause of this disaster appears to have been the clogging of the No. 4 filter, which caused excessive pressure in filter box No. 3, causing it to blow out through the water seal. From five to ten minutes’ delay occurred before the central valve could be operated to stop the escaping gas, during which time an immense volume of gas-air explosive mixture accumulated in the upper part of the purifying house, where in my opinion, it became ignited by the electric sparks issuing from apparatus unfortunately installed in its path.
In my opinion, some other method than having a man constantly watching a pressure gauge, should be employed to give warning that a filter had become clogged to the extent that it caused excessive pressure of gas.
Inadequacy of Central Valve
Unreasonable time elapsed in the operation of the gentral valve to shut off the escaping gas. This valve should have been considered an emergency device and should have been installed so as to afford greater facility of operation. The fact that it required five men under normal conditions to operate this valve and six men in this emergency when its operation was too slow to prevent this disaster, shows the employment of an inadequate device.
It is evident that just previous to the explosion the entire premises of the purifying house contained a large amount of escaping gas. The maintenance of sparking electrical apparatus, fifty feet in the air in the direct path of a possible escape of a gas that is four-tenths the weight of air and consequently rises when liberated, is, in my opinion, improper. Induction motors could have been employed for these elevators, or the electric hoisting machinery could have been installed in the basement where the gas, owing to its gravity, would not reach it, or hydraulic elevators could have been employed.