
NOTE: 1. All dimensions are from the tube surface.
2. Clearances B, C and D can be reduced by 50% for
locations 25 ft. (8 m) or more downstream of the burner.
R O B E R T S
-
G O R D O N
S E C T I O N
4 :
C L E A R A N C E S T O C O M B U S T I B L E S
pg 7
A
C
B
D
C
D
B
A
Figure 1f. U-Tube, Opposite 45°
Figure 1g. U-Tube, Full 45°
Radiant tubes
Vent
Pipes
Unvented
Vented
A
E
F
Figure 1h. Venting
Inches
Metric (cm)
Model
A
B
C
D
HE-40
-
-
-
-
HE-60
8
54
60
22
HE-80
8
60
66
22
HE-100
10
64
74
22
HE-125
10
70
78
22
HE-150
12
74
84
22
HE-175
12
76
85
22
Model
A
B
C
D
HE-40
-
-
-
-
HE-60
20
135
150
55
HE-80
20
150
165
55
HE-100
25
160
185
55
HE-125
25
175
195
55
HE-150
30
185
210
55
HE-175
30
190
213
55
Model
A
B
C
D
HE-40
-
-
-
-
HE-60
8
8
60
42
HE-80
8
8
66
46
HE-100
8
8
74
52
HE-125
8
8
78
61
HE-150
8
8
84
66
HE-175
8
8
85
70
Model
A
B
C
D
HE-40
-
-
-
-
HE-60
20
20
150
105
HE-80
20
20
165
115
HE-100
20
20
185
130
HE-125
20
20
195
153
HE-150
20
20
210
165
HE-175
20
20
213
175
Model
A
E
F
HE-40
14
18
18
HE-60
14
18
18
HE-80
20
24
18
HE-100
20
24
18
HE-125
20
24
18
HE-150
20
30
18
HE-175
20
30
18
Model
A
E
F
HE-40
35
45
45
HE-60
35
45
45
HE-80
50
60
45
HE-100
50
60
45
HE-125
50
60
45
HE-150
50
75
45
HE-175
50
75
45