FOREST SERVICE WATER SPRAY DRY KILN. 
47 
All pipe used inside the kilns should be genuine wrought iron, 
not steel, and should not be galvanized. 
All exposed runs of piping should be covered with a suitable air- 
cell pipe covering. The cold-water main should be covered with a 
moisture-proof pipe covering 
All controlling valves should be angle or gate valves except in 
special cases. Where globe valves are used they should be set with 
the stem horizontal, to avoid water or steam pockets. 
Table 10. — Standard wrought-iron pipe. 
[Hoffman's Handbook for heating and ventilating engineers.] 
Length 
Length 
Trade 
size. 
Ex- 
ternal 
size. 
In- 
ternal 
size. 
Internal 
area. 
of pipe 
per 1 
square 
foot of 
area. 
of pipe 
con- 
taining 
1 cubic 
foot. 
Surface 
per lin- 
ear foot 
ofpipe. 
Nominal 
weight 
per foot. 
Weight of 
water per 
linear foot. 
Inches. 
Inches. 
Inches. 
Sq. in. 
Feet. 
Feet. 
Sq.feet. 
Pounds. 
Pounds. 
3. 
1.050 
.824 
.5333 
3.637 
270.0 
.275 
1.115 
.230 
1 
1.315 
1.048 
.8609 
2.904 
166.9 
.346 
1.668 
.373 
1! 
1.660 
1.380 
1.496 
2. 301 
96.25 
.434 
2.244 
.648 
1.900 
1.611 
2.038 
2.010 
70.66 
.494 
2.678 
.883 
2 
2.375 
2.067 
3.356 
1.608 
42.91 
.622 
, 3.609 
1.454 
2i 
2.875 
2.468 
4.780 
1.328 
30.10 
.753 
5.739 
2.072 
3 
3.500 
3.067 
7.388 
1.091 
19.50 
.916 
7.536 
3.202 
4 
4.500 
4.026 
12. 730 
.849 
11.31 
1.175 
10. 665 
5.517 

5.563 
5.045 
19.985 
.687 
7.20 
1.455 
14. 502 
8.668 
6 
6.625 
6.065 
28.886 
.577 
4.98 
1.739 
18. 762 
12. 521 
7 
7. 625 
7.023 
38. 743 
.501 
3.72 
1.996 
23.271 
16.790 
8 
8.625 
7.982 
50. 021 
.443 
2.88 
2.257 
28.177 
21. 688 
Table 
11. — Water conversion factors . x 
United States gallons 
X 
8. 33 = pounds. 
United States gallons 
X 
0. 13368 =cubic feet. 
United States gallons 
X 
231. 00000 =cubic inches. 
Cubic inches of water (39.1°) X 
0. 036024=pounds. 
Cubic inches of water (39.1°) X 
0. 004329=United States gallons. 
Cubic feet of water 
(39.1°) X 
62. 425 =pdunds. 
Cubic feet of water 
(39.1°) X 
7. 48 = United States gallons. 
Cubic feet of water 
(39.1°) X 
0. 028 =tons. 
Pounds of water 
X 
27. 72 =cubic inches. 
Pounds of water 
X 
0.01602 =cubicfeet. 
Pounds of water 
X 
0. 12 * = United States gallons. 
i American Machinist Handbook. 
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