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American Society of Heating and Ventilating Engineers Guide, 1932
for insulating such surfaces. Table 3 shows the areas of both standard . and extra heavy flanged fittings including the accompanying flanges bolted to the fittings.
Fig. 1.' Chart for Estimating Dollar Value of Heat Loss j from Bare Iron Pipes. (See Table l)a
This chart is based on 100. linear feet per 1000'hours- . For fractions or multiples.of. these factors,.
miiltiplyr by proper percentage.
1
''
, ; INSULATION OF IIOT WATER, ANDSTEAM LINES ;
The conductivities of various materials used for insulating steam and hot: water pipes are given in Table 4. In this table the conductivities are givemas functions of the mean temperaturesor the mean of the inner andi
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Chapter 12--Pipe ' Insulation . i.: ...
outer surface temperatures of the insulations. This method of stating conductivities makes it possible readily to calculate the heat loss through single or compound sections. It should be emphasized that the con ductivities given in Table 4 for the various insulations are the average of values obtained from a number of tests made on each type of material, also that all variables due to differences in thickness, pipe sizes, and air
Table 1. Heat Tosses from Horizontal Bare Iron Pipes
Expressed in Btu per linear fapt per degree Fahrenheit difference in temperature between the pipe and surrounding still air at 70 F.
Nominal Pipe Size .
(Inches)
H
3A
l m
i'A .2 \2'A: ,3 3'A 4
.4H
5 6 8 9
12
120 F
Hot Water
150 F
180 F
210 F
227.2 F (5 Lb)
Temperature Difference
Steam
298.7 F (10 Lb)
337.9 F (100 Lb)
50 F
80 F
0.543 0.660 0.791 0.979 1.09 1.34
1.58 1.88 2.13 2.36 2.60 2.87 3.39 4.32 .4.80 . 6.25
0.573 0.690 0.829 1.02 1.15 1.40 1.67 1.99 2.24 2.50 2.75 3:02 3:56 4-. 55 5.05 6.62
110 F
140 F
0.605
0.638
0.729
0.762
0.878
0.920
1.087
1.15
1.220
1.29
1.491
1.58
1.778
1.87
2.100
2.22
2.380
2.51
2.650
2.78
2.920
3.08
.3.200
3.38
3.775
4.01
5.050 - - 5.14 -
5.350
5.71
6.995
7.46
157.2 F
228.7 F
267.9 F
0.656 0.781 0.953 1.184 1.335 1.637 1.937 2.301 2.585 2.873 3.170 3.493 -4.115 . 5.270 5.885 7.670
0.742
0.796
0.886
0.955
1.084
1.166
1.345
1.450
1.520
1.640
1.866
2.015
2.215
2.388
2.641
21853
. 2.972 ' ' 3.215
3.312
3.582
3.655
3.956
4.030 . .4.368
4.755
5.153
6.120
6.635
6.824
7.400
8.900
9.670
Table 2. Radiating Surface per Linear Foot of Pipe
Nominal Pips Size (Inches)
a
'A
i.
ik
IK
Surface Area
(Sq Ft)
0.22 0.275 0.344 0.435 . 0.498
1 Nominal | Pipe Size
(Inches)
I2 i'A 3 3'A
| ..4.
Surface Area
(Sq Ft)
. 0.622 0.753 0.917 1.047 1.178
.
Nominal Pipe Size (Inches)
5 .6
8. 9 12
Surface Area
' (Sq Ft)
1.456 1.734 2.257 2.519 3.338
.\
conditions are eliminated. Individual .manufacturer's materials will, of course, vary in conductivity to-some extent from these values.
The heat losses through six of the types of insulation given in Table 4 for 1, TJ^ and 2-in. thick materials, and for temperatures commonly encountered in engineering practice can be obtained from. Tables 5 to 10, inclusive. The loss through other thicknesses of the materials, and for other hot water or steam temperature conditions may be obtained by interpolation. The heat loss coefficients given in Tables'5 to 10 were
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