In the use of steam tables, steam drums, etc., in manufacturing processes, very careful consideration should be given, from the safety standpoint, to the details of installation and manipulation, so as to avoid all chance of overpressure or uneven expansion from too rapid heating, either of which might result in an explosion. While the bursting of such devices would not be expected to cause such serious results as a boiler explosion (since less energy is involved), the location of the devices directly in factory rooms with many employees near by makes it possible for an explosion of even small magnitude to result in serious or fatal injury, from flying parts, from escaping steam and from panie which is very likely to follow.

The illustration in Fig. 23 shows an exploded cylinder of a laundry flat-work ironer, which occurred while it was being heated up for the day's work. The bolts which hold the head on to the cylinder failed, partly from defective design and partly from old flaws or "progressive fractures" which had developed from repeated heating and cooling. The explosion not only wrecked the machine itself as shown, but also blew out the side of the building. Several fatalities would undoubtedly have resulted had the explosion not occurred, fortunately, outside of working hours, so that no person happened to be in the room at the time.

All factory devices that operate under steam pressure should be carefully designed to insure ample factors of safety. Where they operate through reducing valves at pressures below that of the boiler supply, safety valves of adequate capacity should be installed on the low-pressure side to prevent building up of pressure in case of defect in the reducing valve. When the device is cold from being out of service, it should be heated up very gradually to avoid the stresses that might be produced by uneven expansion, and reliable arrangements to prevent accumulation of water or condensation should be provided. since in case of failure the presence of condensation would add materially to the energy of the explosion. The steam cylinder should also be revolved while it is being warmed up, to prevent expansion and contraction stresses resulting from unequal heating.

The horizontal belts used to drive the vertical spindles of multiple drills, radial drills, boring machines, etc., have a special element of hazard, due to the fact that the operator's eyes are often in close prox imity to the moving belt, and might be injured in case the belt should break or a lacing work loose. This danger can be readily eliminated by a simple band guard placed across the danger point, as illustrated in Fig. 24.

The manual method of resuscitation which the association recommends is that approved by the Commission on Resuscitation of the National Electric Light Association, the so-called "Prone Pressure Method." Fig. 25 shows the two essential positions of the method, —the upper one that of inspiration and the lower that of expiration.