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NOTE: Maximum Equivalent Vent Length (MEVL) includes standard and concentric vent termination and does NOT include elbows.
Use Table 15 - Deductions from Maximum Equivalent Vent Length to determine allowable vent length for each application.
Unit Size
Pipe Dia. (in)
0--- 2000
2001--- 3000
3001--- 4000
4001--- 4500
Altitude
4501--- 5000
(feet)
5001--- 6000
6001--- 7000
7001--- 8000
8001--- 9000
9001--- 10000
Unit Size
Pipe Dia. (mm)
0--- 610
611--- 914
915--- 1219
1220--- 1370
Altitude
1371--- 1524
(meters)
1525--- 1829
1830--- 2134
2135--- 2438
2439--- 2743
2744--- 3048
ELBOW CONFIGURATIONS
Long
Medium
Pipe Diameter (in):
Mitered 90º Elbow
Medium Radius 90º Elbow
Long Radius 90º Elbow
Mitered 45º Elbow
Medium Radius 45º Elbow
Long Radius 45º Elbow
Tee
Concentric Vent Termination
Standard Vent Termination
NOTES:
1. Use only the smallest diameter pipe possible for venting. Over ---sizing may cause flame disturbance or excessive vent terminal icing or freeze ---up.
2. NA --- Not allowed. Pressure switch will not close, or flame disturbance may result.
3. Vent sizing for Canadian installations over 4500 ft. (1370 M) above sea level are subject to acceptance by the local authorities having jurisdiction.
4. Size both the combustion air and vent pipe independently, then use the larger size for both pipes.
5. Assume the two 45_ elbows equal one 90_ elbow. Wide radius elbows are desirable and may be required in some cases.
6. Elbow and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
7. The minimum pipe length is 5 ft. (2 M) linear feet (meters) for all applications.
8. Use 3 ---in. (76 mm) diameter vent termination kit for installations requiring 4 ---in. (102 mm) diameter pipe.
Table 14 – Maximum Equivalent Vent Length - - Ft.
60,000
1 ½
2
2 ½
3
1 ½
50
100
175
200
30
45
95
165
185
40
90
155
175
25
85
170
23
35
150
80
165
22
37
75
140
155
35
70
130
145
20
32
66
120
135
18
30
62
115
125
17
27
57
105
115
15
60,000
38
51
64
76
38
15.2
30.4
53.3
60.9
9.1
13.7
28.9
50.2
56.3
12.1
27.4
47.2
53.3
7.6
25.9
51.8
7.0
10.6
45.7
24.3
50.2
6.7
11.2
22.8
42.6
47.2
10.6
21.3
39.6
44.1
6.0
9.7
20.1
36.5
41.1
5.4
9.1
18.8
35.0
38.1
5.1
8.2
17.3
32.0
35.0
4.5
Mitered
Table 15 – Deductions from Maximum Equivalent Vent Length - - Ft. (M)
1-1/2
8
(2.4)
5
(1.5)
3
(0.9)
4
(1.2)
2.5
(0.8)
1.5
(0.5)
16
(4.9)
NA
0
(0.0)
Ft.
80,000
2
2 ½
3
4
95
130
175
200
125
165
185
115
155
175
150
165
70
110
145
160
100
135
150
125
140
90
66
120
125
62
80
110
115
57
75
100
105
Meters
80,000
51
64
76
102
28.9
39.6
53.3
60.9
38.1
50.2
56.3
35.0
47.2
53.3
45.7
50.2
21.3
33.5
44.1
48.7
30.4
41.1
45.7
38.1
42.6
27.4
20.1
36.5
38.1
18.8
24.3
33.5
35.0
17.3
22.8
30.4
32.0
VENT TERMINAL CONFIGURATIONS
Concentric
2
2-1/2
8
(2.4)
8
5
(1.5)
5
3
(0.9)
3
4
(1.2)
4
2.5
(0.8)
2.5
1.5
(0.5)
1.5
16
(4.9)
16
0
(0.0)
NA
0
(0.0)
0
54
100,000
2
2 ½
3
4
45
80
175
200
40
165
185
75
38
175
155
170
36
150
165
70
33
140
155
31
135
145
29
66
125
135
27
62
115
125
24
57
100
115
100,000
51
64
76
102
13.7
24.3
53.3
60.9
12.1
50.2
56.3
22.8
11.5
53.3
47.2
51.8
10.9
45.7
50.2
21.3
10.0
42.6
47.2
9.4
41.1
44.1
8.8
20.1
38.1
41.1
8.2
18.8
35.0
38.1
7.3
17.3
30.4
35.0
Standard 2-in., 3-in., or
optional 4-in. termination.
3
(2.4)
8
(2.4)
(1.5)
5
(1.5)
(0.9)
3
(0.9)
(1.2)
4
(1.2)
(0.8)
2.5
(0.8)
(0.5)
1.5
(0.5)
(4.9)
16
(4.9)
0
(0.0)
(0.0)
0
(0.0)
120,000
2 ½
3
4
75
185
10
70
175
5
65
165
160
60
155
N/A
50
140
46
130
43
120
39
115
120,000
64
76
102
22.8
56.3
3.0
21.3
53.3
1.5
19.8
50.2
48.7
18.2
47.2
NA
15.2
42.6
14.0
39.6
13.1
36.5
11.8
35.0
A13110
4
8
(2.4)
5
(1.5)
3
(0.9)
4
(1.2)
2.5
(0.8)
1.5
(0.5)
16
(4.9)
NA
0
(0.0)
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