In the case of Cornish, Lancashire, and other boilers with internal flues, the faults of construction which have caused explosions have been weakness in the tubes, combustion chambers, ends, domes, or manholes; and explosions in these, as in other classes of boilers, have also resulted from external or internal corrosion, shortness of water, undue pressure of steam, and scale or mud on the boiler plates.
In plain cylindrical boilers, and others without internal flues, explosions have resulted from the boiler ends being made flat, and also from frequent repairs producing seam rips, especially in boilers having the plates arranged lengthways instead of in rings.
In marine boilers, weak flues and weak ends have also led to explosion, in addition to the other causes mentioned above.
Locomotive boilers have in two cases exploded in consequence of the strains thrown upon them by their being used as a frame for the engine.
Other explosions have resulted from want of stays, and from too much heat impinging on some particular part; and in domestic boilers from freezing of pipes under pressure.
Altogether the total number of explosions in this country that have been recorded during the past four years has amounted to 219, which may be classed under the following heads:—
| Faults of construction or repair | 95 |
| Faults to be detected only by periodical examination | 62 |
| Faults which should be prevented by careful attendants | 54 |
| Extraneous or uncertain causes | 8 |
| Total | 219 |
By these 219 explosions 315 persons were killed and 450 injured.
The following are the particulars of the construction of the 219 exploded boilers:—