ICP N9MSB - Vent Length Calculation Tables and Figures; Maximum Equivalent Vent Length Table; Deductions from MEVL Table

Altitude
FT (M)
N9MSB & N9MSE - MAXIMUM EQUIVALENT VENT LENGTH - Feet (Meters)
Note: Maximum Equivalent Vent Length (MEVL) does NOT include elbows or terminations
Use Table 15 - DEDUCTIONS FROM MEVL to determine allowable vent len,qth for each application.
DIRECT VENT (2-PIPE) AND NON-DIRECT VENT (1-PIPE)
Unit Size Vent Pipe Diameter (in,)
Table 14
1-1/2
(15.2) 210
(9.1) 1135
70
2 2-1/2 3 4
(76.2)
(71.6)
(53.3)
(33.5)
(4.6)
(3.0)
(70.7)
(67.7)
(50.3)
(31.7)
(3.4)
BTU/Hr
40,000 3 50 (64.0) 250
60,000 I 30 (41.1) 235 265 (80.8)
0 to 2000 80,000 (21.3) 175 235 (71.6) 265 (80.8)
(0 to 610) 100,000 25 (7.6) 110 235 (71.6) 265 (80.8)
120,000 15 100 (30.5) 250 (76.2)
140,0004 10 90 (27.4) 210 (64.0)
40,000 I 45 (13.7) I 198 (60.4) 232
60,000 I 27 (8.2) 1127 (38.7) 222 250 (76.2)
2001 to 3000 80,000 64 (19.5) 165 222 (67.7) 249 (75.9)
(610 to 914) 100,000 22 (6.7) 104 223 (68.0) 250 (76.2)
120,000 1t 93 (28.3) 237 (72.2)
140,0004 80 (24.4) 185 (56.4)
40,000 I 39 (11.9) I 184 (56.1) 214 (65.2)
60,000 I 23 (7.0) 1 119 (36.3) 210 (64.0) 235 (71.6)
3001 to 4000 80,000 59 (18.0) 155 (47.2) 210 (64.0) 232 (70.7)
(914 to 1219) 100,000 19 (5.8) 98 (29.9) 211 (64.3) 236 (71.9)
120,000 8 (2.4) 86 (26.2) 224 (68.3)
140,0004 79 (24.1) 158 (48.2)
40,000 I 36 (11.0) I 177 (53.9) 205 (62.5)
60,000 I 21 (8.4) 1 115 (35.1) 204 (62.2) 228 (69.5)
4001 to 4500 80,000 56 (17.1) 150 (45.7) 202 (61.6) 224 (68.3)
(1219 to 1370) 100,000 17 (5.2) 94 (28.7) 205 (62.5) 229 (69.8)
120,000 83 (25.3) 217 (66.1)
140,0004 69 (21.0) 146 (44.5)
See notes at end of Venting Tables
See Table 16 for altitudes over 4500 ft (1370m).
Figure 60 _Elbows Configurations
MEDIUM MITEREDLONG
L11F082
Figure 61 Vent Terminal Configurations
L11F083
L11F084
Table 15
Pipe Diameter (in):
Mitered 90 -0Elbow
Medium Radius 90-0 Elbow
Long Radius 90-0Elbow
Mitered 45 -0Elbow
Medium Radius 45 -0Elbow 2.5
Long Radius 45 -0Elbow 1.5
Tee 16
* Note: 3- and 4-in. vent pipe systems require long radius elbows,
Venting System Length Calculations
DEDUCTIONS FROM MAXIMUM EQUIVALENT VENT LENGTH - Feet (Meters)
1-1/2 2 2-1/2 3 4
8 (2.4) 8 (2.4) 8 (2.4) 8 (2.4) 8 (2.4)
5 (1.5) 5 (1.5) 5 (1.5) 5 (1.5) 5 (1.5)
3 (0.9) 3 (0.9) 3 (0.9) 3 (0.9) 3 (0.9)
4 (1.2) 4 (1.2) 4 (1.2) 4 (1.2) 4 (1.2)
(0.8) 2.5 (0.8) 2.5 (0.8) 2.5 (0.8) 2.5 (0.8)
(0.5) 1.5 (0.5) 1.5 (0.5) 1.5 (0.5) 1.5 (0.5)
(4.9) 16 (4.9) 16 (4.9) 16 (4.9) 16 (4.9)
The Total Equivalent Vent Length for EACH combustion air or vent pipe equals the length of the venting system, plus the equivalent
length of elbows used in the venting system from Table 15.
Standard vent terminations or factory accessory concentric vent terminations count for zero deduction.
See vent system manufacturer's data for equivalent lengths of flexible vent pipe or other termination systems. DO NOT ASSUME
that one foot of flexible vent pipe equals one foot of straight PVC/ABS DWV vent pipe.
Compare the Total Equivalent Vent Length to the Maximum Equivalent Vent Lengths in Table 14 and Table 16.
440 01 4101 03 Specifications subject to change without notice. 53