Q. The accompanying sketch, Figure 115, shows the arrangement of six bath-boiler systems in a building in New York, constructed to rent in separate stories or flats. We would like the views of other plumbers-as to the cause of bursting of the lead vent-pipes B, B, B, B, B, B, and suggestions as to methods of remedying the difficulty. The fractures do not present the appearance of frost burst, but where the break occurs the lead looks like burned or dried sole-leather. The lead looks puckered or crumpled near the break. We know it is caused by the action of steam. The ranges are Mott's "G" ranges, of small size, and the boilers thirty-five gallons. We suggested to put a fire-brick or soapstone in front of the water-back, but the boiler being so small there is already complaint of a deficient supply of hot water, and this method of limiting the heat in the pipes is not approved, although when all the hot water is not used the boilers get very hot. The pipes do not burst in any particular place or at any given distance from the boiler, nor does the season of the year seem to have anything to do with the bursting, as might have been supposed, for at times the vapor freezes on the roof. Might not a circulating-pipe at about the level of the tank (so that the system of pipe would always be full of water) down to the bottom of the water-back remedy the trouble? We would be pleased to-have this question discussed by experts in the plumbing business.

Figure 115.

A. An experienced plumber of New York City, to whom this was referred, says that, judging from the samples of pipe shown him, it probably came from a bend where the weight of lead above had caused it to bend out of the vertical at a place where it was not securely fastened to the wall or other support. The particles on the inner side of the bend tend to crowd each other out, and the tendency was yielded to at the ruptured place on account of imperfect lead. The strain on these pipes from contraction and expansion, and also from the shock given by the closing of supply-cocks, is very great, from their great length and heavy weight, and they break at the weakest points, where the metal is poor.

Another experienced plumber says: "From the description given with the cut, and inferring from the additional notes, we suppose the pipes to be of lead, in which case it is not always necessary to generate steam to cause them to burst, though from your description of looks of the material where burst, it is very likely that steam has been at times generated. We have on several occasions heretofore advised against the use of lead pipe for water-back connections, and the same is true in regard to hot-water pipes, especially so in small boilers, where the hot water is entirely drawn off and is replaced by cold water."

The inferences which we draw from the sketch and description are: (1) That the bath-boilers are too small for the service of hot water, as well as too small for the water-backs, so that in the common usage of the ranges the water in the boiler becomes overheated to the point where steam is generated under the small pressure which these low vent-pipes will produce. It would seem that the water and steam commingled in all of the vent-pipes ought to be lifting frequently, and especially in the vent-pipes in the uppermost stories. (2) It is inferred that the lead vent-pipes are confined or held without adequate freedom to expand and contract, or to crawl. As is suggested, lead is a poor material for pipes likely to be hot and cold; it is nearly worthless for a steam-pipe at any pressure, failing sooner or later, much as is described. Gal-vanized-iron pipes suspended from the top, or securely held at the bottom and free to rise at the top, are certainly preferable to lead pipes in this place.

The proposition for a circulating-pipe will not meet approval unless the upper bend be made in a small tank or vessel, where the steam can separate, which tank should be a closed one, with a safety-valve headed to a little less than the supply-tank head. Thus arranged the circulation would become solid, and not a 'geyser-like" ebullition.