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References
Heat Losses From Insulated Pipe
Heat Losses From Bare Steel Pipe Based on 70°F Surrounding Air
85 Percent Magnesia Type
BTU per Linear Foot Per Hour Per °F
Difference (Surrounding Air Assumed 75°F)
Temperature of Pipe, °F
Diameter of Pipe
(inches)
100
200
150
180
210
240
Heat Loss per Lineal Foot of Pipe - BTU per Hour
1/2
13
22
40
60
82
106
3/4
15
27
50
74
100
131
1
19
34
61
90
123
160
1-1/4
23
42
75
111
152
198
1-1/2
27
48
85
126
173
224
2
33
59
104
154
212
275
2-1/2
39
70
123
184
252
327
3
46
84
148
221
303
393
3-1/2
52
95
168
250
342
444
4
59
106
187
278
381
496
Pipe Size
(inches)
8
105
1/4
4
8
14
21
3/8
6
1/2
7
5/8
3/4
29
37
10
18
13
22
28
37
48
33
45
59
8
15
26
39
53
9
17
30
45
61
Max. Temp. of Pipe Surface °F
125
175
225
275
0.160
1/2
1
0.145
0.150
0.157
3/4
1
0.165
0.172
0.177
0.180
1
0.190
0.195
0.200
0.203
1-1/2
0.160
0.165
0.167
0.170
1
0.220
0.250
0.232
0.237
1-1/2
0.182
0.870
0.193
0.197
0.260
1
1-1/4
1-1/2
Heat Losses From Bare Copper Pipe Based on 70°F Surrounding Air
Insulation
Thickness
(inches)
2
1
0.240
0.247
0.255
1-1/2
0.200
0.205
0.210
0.215
1
0.282
0.290
0.297
0.303
1-1/2
0.230
0.235
0.240
0.243
2
0.197
0.200
0.205
0.210
1
0.322
0.330
0.340
0.345
1-1/2
0.260
0.265
0.270
0.275
68
2
0.220
0.225
0.230
0.237
79
1
0.375
0.385
0.395
0.405
1-1/2
0.300
0.305
0.312
0.320
2-1/2
1
11
21
37
55
75
97
1-1/4
14
25
45
66
90
117
2
0.253
0.257
0.263
0.270
1-1/2
16
29
52
77
105
135
1
0.419
0.430
0.440
0.450
2
20
37
66
97
132
171
1-1/2
0.332
0.340
0.345
0.352
2-1/2
24
44
78
117
160
206
2
0.280
0.285
0.290
0.295
1
0.460
0.470
0.480
0.492
3
28
51
92
136
186
240
3-1/2
32
59
104
156
212
274
4
36
66
118
174
238
307
3
3-1/2
4
90
91
1-1/2
0.362
0.370
0.379
0.385
2
0.303
0.308
0.315
0.320
8
105