54
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.
Table 14 – Maximum Equivalent Vent Length -- Ft.
Ft.
Unit Size 60,000 80,000 100,000 120,000
Altitude
(feet)
Pipe Dia. (in) 1½ 2 2½ 3 1½ 2 2½ 3 4 2 2½ 3 4 2½ 3 4
0--- 2000 50 100 175 200
30
95 130 175 200 45 80 175 200
10
75 185
2001--- 3000 45 95 165 185
70
125 165 185 40
75
165 185 70 175
3001--- 4000 40 90 155 175 25 115 155 175 38
155
175 5 65 165
4001--- 4500
35
85
150
170 23
110
150 165
36
70
170
N/A
60
160
4501--- 5000 80 165
22
145 160 150 165
5001--- 6000 37 75 140 155 100 135 150 33 140 155 155
6001--- 7000 35 70 130 145 20
90
125 140 31 135 145 50 140
7001--- 8000 32 66 120 135 18 66 120 125 29 66 125 135 46 130
8001--- 9000 30 62 115 125 17 62 80 110 115 27 62 115 125 43 120
9001--- 10000 27 57 105 115 15 57 75 100 105 24 57 100 115 39 115
Meters
Unit Size 60,000 80,000 100,000 120,000
Altitude
(meters)
Pipe Dia. (mm) 38 51 64 76 38 51 64 76 102 51 64 76 102 64 76 102
0 --- 6 1 0 15.2 30.4 53.3 60.9
9.1
28.9 39.6 53.3 60.9 13.7 24.3 53.3 60.9
3.0
22.8 56.3
611--- 914 13.7 28.9 50.2 56.3
21.3
38.1 50.2 56.3 12.1
22.8
50.2 56.3 21.3 53.3
915--- 1219 12.1 27.4 47.2 53.3 7.6 35.0 47.2 53.3 11.5
47.2
53.3 1.5 19.8 50.2
1220--- 1370
10.6
25.9
45.7
51.8 7.0
33.5
45.7 50.2
10.9
21.3
51.8
NA
18.2
48.7
1371--- 1524 24.3 50.2
6.7
44.1 48.7 45.7 50.2
1525--- 1829 11.2 22.8 42.6 47.2 30.4 41.1 45.7 10.0 42.6 47.2 47.2
1830--- 2134 10.6 21.3 39.6 44.1 6.0
27.4
38.1 42.6 9.4 41.1 44.1 15.2 42.6
2135--- 2438 9.7 20.1 36.5 41.1 5.4 20.1 36.5 38.1 8.8 20.1 38.1 41.1 14.0 39.6
2439--- 2743 9.1 18.8 35.0 38.1 5.1 18.8 24.3 33.5 35.0 8.2 18.8 35.0 38.1 13.1 36.5
2744--- 3048 8.2 17.3 32.0 35.0 4.5 17.3 22.8 30.4 32.0 7.3 17.3 30.4 35.0 11.8 35.0
Long
Medium
Mitered
Concentric
Standard 2-in., 3-in., or
optional 4-in. termination.
ELBOW CONFIGURATIONS
VENT TERMINAL CONFIGURATIONS
A13110
Table 15 – Deductions from Maximum Equivalent Vent Length -- Ft. (M)
Pipe Diameter (in): 1-1/2 2 2-1/2 3 4
Mitered 90º Elbow 8 (2.4) 8 (2.4) 8 (2.4) 8 (2.4) 8 (2.4)
Medium Radius 90º Elbow 5 (1.5) 5 (1.5) 5 (1.5) 5 (1.5) 5 (1.5)
Long Radius 90º Elbow 3 (0.9) 3 (0.9) 3 (0.9) 3 (0.9) 3 (0.9)
Mitered 45º Elbow 4 (1.2) 4 (1.2) 4 (1.2) 4 (1.2) 4 (1.2)
Medium Radius 45º Elbow 2.5 (0.8) 2.5 (0.8) 2.5 (0.8) 2.5 (0.8) 2.5 (0.8)
Long Radius 45º Elbow 1.5 (0.5) 1.5 (0.5) 1.5 (0.5) 1.5 (0.5) 1.5 (0.5)
Tee 16 (4.9) 16 (4.9) 16 (4.9) 16 (4.9) 16 (4.9)
Concentric Vent Termination NA 0 (0.0) NA 0 (0.0) NA
Standard Vent Termination 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0)
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 Can a dian installations over 4500 ft. (1370 M) above sea level a re subject to acceptance by the local a uthorities 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.
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