It is therefore necessary in laying out the boiler room of a manufacturing plant to consider carefully the character of the steam generator and study its requirements, so that it may be successfully operated and the proper spaces allotted.

Fig. 30

61. Doorway to Engine and Boiler Room.—In the hasty design of buildings, it is frequently found that the size of the doorways is not sufficient to admit the boilers and machinery. This is a serious defect in the planning of a manufacturing plant, as it requires either the installation of the boilers and engines before the walls are entirely built, or else the tearing out of brickwork and jambs in order to accommodate them afterwards. An expedient for the enlargement of the headroom of doorways and openings into the boiler and engine rooms that are in the basement, is shown in [Fig. 30]. Here, if the lintel of the doorway a is kept below the floor level, where it would ordinarily exist, the headroom of the doorway will be materially reduced, and considerable difficulty will be encountered in taking any large piece of machinery, or a boiler or steam drum, down the steps b. The doorway is consequently increased in height by the introduction of the bulkhead at c; while by this means the floor space above is slightly reduced, yet use can frequently be found for the ledge or platform frame at the top of the bulkhead, as at d.

62. Floors Above Boilers.—It is important in designing boiler rooms in factories to have the floor construction over the top of the boiler of incombustible material, and it is customary in the better class of buildings to provide a section of fireproof floor over the top of the boiler room. This floor construction may either be a brick arch supported on steel beams, or hollow-tile construction, though reinforced concrete is now finding favor in this purpose.

63. It is not altogether necessary that the boilers in a building shall be placed in the basement, though as this is usually the least valuable of the floor space it is the practice to so locate them. In some electric-light stations, and in large factories, boilers have been located on the first floor, and even in several instances on the fifth and sixth floors. The exigencies that demand the latter installation, however, must be great, for it can be readily seen that much power must be expended in lifting the coal, etc. to the boiler room.

CHIMNEYS

64. Dimensions and Capacity of Chimneys. Nearly all the factory buildings combine in their structure a power plant, not the least important feature of which is the chimney. There are two things to consider in the design of a power chimney—first, its capacity for providing the necessary draft and the conduction of the requisite volume of gases from the furnace or boiler, and second, its stability. The first requirement regulates its diameter and height, and these dimensions, together with its construction, determine also its stability.

TABLE I

Diam-
eter
In.		 Height of Chimneys and Commercial Horsepower Capacity Side
of
Square
Inches		Effective
Area
Square
Ft.		Actual
Area
Square
Ft.
50
Ft.		60
Ft.		70
Ft.		80
Ft.		90
Ft.		100
Ft.		110
Ft.		125
Ft.		150
Ft.		175
Ft.		200
Ft.
18  23  25 27 16   .97  1.77
21  35  38 41 19  1.47  2.41
24  49  54 58  62 22  2.08  3.14
27  65  72 78  83  87 24  2.78  3.98
30  84  92100 107 113119 27  3.58  4.91
33 105 115125 133 141149 30  4.48  5.94
36 128 141152 163 173182 191 32  5.47  7.07
39 154 168183 196 208219 229 35  6.57  8.30
42 182 200216 231 245258 271 288 38  7.76  9.62
48 269290 311 330348 365 389 43 10.44 12.57
54 348376 402 427449 472 503 551 48 13.51 15.90
60 436471 503 536565 593 632 692  748 54 16.98 19.64
66 579 620 658694 728 776 849  918  98159 20.83 23.76
72 698 746 792835 876 9341,023 1,105 1,18164 25.08 28.27
78 885 949990 1,038  1,1071,212 1,310 1,40070 29.73 33.18
84 1,035  1,098 1,157  1,214  1,2941,418 1,531 1,63775 34.76 38.48
90 1,269 1,338  1,403  1,4961,639 1,770 1,89380 40.19 44.18
96 1,532  1,606  1,7121,876 2,027 2,16786 46.01 50.27
100 1,760  1,8652,043 2,197 2,35989 50.11 54.54
104 1,899  2,0242,218 2,395 2,56093 54.39 59.00
108 2,051  2,1902,399 2,591 2,77096 58.83 63.62
112 2,3232,588 2,795 2,983100  63.46 68.42
118 2,6322,883 3,114 3,339105  70.71 75.94
120 2,7252,986 3,225 3,447107  73.22 78.54
124 2,9153,193 3,449 3,687110  78.31 83.86
130 3,1653,467 3,745 4,004116  85.04 90.76
136 3,868 4,178 4,466121  94.85 100.88
142 4,305 4,567 4,886126  103.69  109.98
150 4,719 5,097 5,448133  115.72  122.72