7
MAXIMUM EQUIVALENT VENT LENGTH -- FT. (M)
Table 1 – Maximum Equivalent Vent Length -- Ft. (M)
0 to 4500 Ft. (0 to 1370 M) Altitude
NOTE: Maximum Equivalent Vent Length (MEVL) includes standard and concentric vent termination and does NOT include elbows.
Use Table 2 - Deductions from Maximum Equivalent Vent Length to determine allowable vent length for each application.
Altitude
FT (M)
Unit Size
BTU/Hr
DIRECT VENT (2-PIPE) AND NON-DIRECT VENT (1-PIPE)
Vent Pipe Diameter (in.)
1
1-1/2
2
2-1/2
3
4
0 to 2000
(0 to 610)
40,000
3
50
(15.2)
210
(64.0)
250
(76.2)
NA
2
NA
60,000
30
(9.1)
135
(41.1)
235
(71.6)
265
(80.8)
NA
80,000
20
(6.1)
70
(21.3)
175
(53.3)
235
(71.6)
265
(80.8)
100,000
NA
25
(7.6)
110
(33.5)
235
(71.6)
265
(80.8)
120,000
NA
NA
15
(4.6)
100
(30.5)
250
(76.2)
140,000
4
NA
NA
10
(3.0)
90
(27.4)
210
(64.0)
2001 to 3000
(610 to 914)
40,000
45
(13.7)
198
(60.4)
232
(70.7)
NA
NA
60,000
27
(8.2)
127
(38.7)
222
(67.7)
250
(76.2)
NA
80,000
17
(5.2)
64
(19.5)
165
(50.3)
222
(67.7)
249
(75.9)
100,000
NA
22
(6.7)
104
(31.7)
223
(68.0)
250
(76.2)
120,000
NA
NA
11
(3.4)
93
(28.3)
237
(72.2)
140,000
4
NA
NA
NA
80
(24.4)
185
(56.4)
3001 to 4000
(914 to 1219)
40,000
39
(11.9)
184
(56.1)
214
(65.2)
NA
NA
60,000
23
(7.0)
119
(36.3)
210
(64.0)
235
(71.6)
NA
80,000
15
(4.6)
59
(18.0)
155
(47.2)
210
(64.0)
232
(70.7)
100,000
NA
19
(5.8)
98
(29.9)
211
(64.3)
236
(71.9)
120,000
NA
NA
8
(2.4)
86
(26.2)
224
(68.3)
140,000
4
NA
NA
NA
79
(24.1)
158
(48.2)
4001 to 4500
(1219 to 1370)
40,000
36
(11.0)
177
(53.9)
205
(62.5)
NA
NA
60,000
21
(6.4)
115
(35.1)
204
(62.2)
228
(69.5)
NA
80,000
14
(4.3)
56
(17.1)
150
(45.7)
202
(61.6)
224
(68.3)
100,000
NA
17
(5.2)
94
(28.7)
205
(62.5)
229
(69.8)
120,000
NA
NA
NA
83
(25.3)
217
(66.1)
140,000
4
NA
NA
NA
69
(21.0)
146
(44.5)
NOTES
: See notes at end of venting tables.
See Table 3 for altitudes over 4500 ft. (1370 M)
Long
Medium
Mitered
Concentric
Standard
ELBOW CONFIGURATIONS
VENT TERMINAL CONFIGURATIONS
A11580
Table 2 – 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)
912SA
