A Terrible Boiler Explosion and Its Lesson


| May/June 1994



Cracked by the boiler maker

Cracked by the boiler maker

Reprinted from American Machinist Vol. 20, No. 50, 1897.

A most disastrous boiler explosion occurred on the afternoon of November 22d at the Graves Elevator Works, Rochester, New York, accompanied by circumstances which make it peculiarly worthy of more than passing notice. The boiler plant was a thoroughly first-class one in every respect. There were two boilers, only one of which was in use at the time of the explosion. It was not old, was well made and well taken care of. There is absolutely no evidence of carelessness or of improper conditions, so far as they could have been known at the time. The usual pressure of 90 pounds was on the boiler at the time of the explosion. The effects were such as should be expected. The boiler was practically blown to pieces; walls were knocked down, and bricks were thrown, some of them to a great distance. The only two persons in the boiler room were instantly killed, and buried under the debris. Three others were seriously injured, and several received slighter wounds. One of the men killed was the regular fireman of the boiler, and the other was Patrick Shields, an inspector of the Hartford Steam Boiler Inspection and Insurance Company. Mr. Shields had been in the boiler room not more than five minutes, and was found seated in a chair, covered with bricks and other material, and shockingly mutilated.

The following extract from a letter from J. M. Allen, president of the Hartford S. B. I. & I. Company gives some additional information, and also reveals the probable cause of the explosion:

'The boiler which exploded in the works of the Graves Elevator Company, of Rochester, New York, by which one of our inspectors lost his life, was a boiler that was only four years old. It was 66 inches diameter, 16 feet long, constructed of ****-inch steel plates; dome, 36 x 39 inches. There were 98 3-inch tubes; was well built and well set, and the boiler room was regarded as one of the best equipped in that vicinity. When the boiler was constructed, the plates were all tested by coupons being sheared from their edges, and the tests were very thorough and very satisfactory.

'Now, as to the cause of the explosion, our chief inspector has made a careful examination, and has satisfied himself that it resulted from one of those incipient cracks that are hidden in the joints by the over-lap of the sheet. We have found several similar cases. The cracks are so located that they cannot be discovered by an inspection, as from an internal inspection the inner lap does not show any fracture whatever, and the outer lap covers the fracture which has not worked through the plate. As to the cause of this kind of fracture, we have pretty well satisfied ourselves that it comes from an effort to bring the plates together at the edges after they have been rolled; that is, the outer lap sometimes 'cocks up' a little above the lower plate, and is brought into place by hammering. We are led to arrive at this conclusion from the fact that, in visiting boiler works, we have seen this kind of practice, and have protested against it, as it is very liable to start an incipient fracture which, under the conditions of use and pressure, is liable to develop into a dangerous weakness. There seems to be no other well-founded reason for such a weakness being developed. The holes are punched in the plate and considerable metal is taken out, and then the effort to bring the lap of the plate together would be liable to bring a pretty severe stress at the points where the plate is forcibly bent.

'I do not wish to be hypercritical in regard to the construction of boilers by the better class of boiler makers, and could not say that this was the practice in the works where this boiler was made; for the boilers are regarded as first class in material and workmanship. At the same time, there seems to be a point which it is well to consider, and which we have written about, and concerning which we have sent out printed information among all the boiler makers of the land.