Steam:
Its Generation and Use

steam pipes will effectually prevent all cracking and pounding noises therein. The amount of air required for ventilation is from 4 to 16 cubic feet per minute for each per- son, the larger amount being for prisons and hos- pitals. From to i cubic foot per minute should be allowed for each lamp or gas burner employed. One square foot of Boiler Surface will supply from 7 to io square feet of radiating surface, de- pending upon the size of boiler and the efficiency of its surface, as well as that of the radiating surface. Small boilers for house use should be by means of pipes placed overhead, is being largely adopted, and is recommended by the Boston Manufacturers’ Mutual Fire Ins. Co. in preference to radiators near the floor, particular- ly for rooms in which there are shafting and belting to circulate the air. In heating buildings care should be taken to supply the necessary moisture to keep the air from becoming “ dry ” and uncomfortable. The capacity of air for moisture rises rapidly as it is heated, it being four times as great at 720 as at 320. For comfort, air should be kept at about “50 per cent, saturated.” This would require Babcock & Wilcox Boiler, 35 H. P., Public School Building, Plainfield, N.J. Erected 1883. much larger proportionately than large plants. Each Horse-power of Boiler will supply from 240 to 360 feet of i-inch steam pipe, or 80 to 120 square feet of radiating surface. Cubic feet of space has little to do with amount of steam or surface required, but is a convenient factor for rough calculations. Under ordinary conditions one horse-power will heat, approx- imately, in Brick dwellings, in blocks, as in cities “ stores “ “ “ dwellings, exposed all round " mills, shops, factories, etc. Wooden dwellings, exposed, Foundries and wooden shops, , . ( u Exhibition buildings, largely glass, etc. 4,000 “ 15,000 The system of heating mills and manufactories 15,000 to 20,000 cub. ft. one pound of vapor to be added to each 2500 cubic feet heated from 320 to 70°. A much needed attachment has recently been introduced, which acts automatically upon the steam valves of the radiators, or upon the hotair registers and ventilators, and maintains the tem- perature in a room to within one-half a degree of any standard desire. A “separator” acting by centrifugal force has been recently tested, and is very efficient, in trapping out all the water entrained in steam. It will be found valuable, particularly where the steam has to be carried a long distance from the boiler, and for the purpose of preventing “ham- mering” of water in the pipes.