Form RGM 433-CV/LN, Mfg No. 177854 (Revision 1), Page 9
Common Venting Tables 3 and 4 Apply to Vertical Common Venting into an Interior, Tile-Lined
Masonry Chimney
Do not vent into an exterior tile-lined masonry chimney.
Before connecting a vent connector to a chimney, inspect the chimney passageway to be sure that it is clear and free of obstructions. Clean the
chimney if it was previously used for venting solid or liquid fuel-burning appliances or fireplaces. Install the vent connector above the extreme
bottom of the chimney. Use a thimble or slip joint to facilitate removal. Attach the connector securely to the thimble. Do not insert the vent
connector into the chimney beyond the chimney wall.
Table 3B - Common Vent Capacity
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
Fan +
Fan
Fan +
Nat
Nat +
Nat
6 N/A 74 25 N/A 119 46 N/A 178 71 N/A 257 103 N/A 351 143 N/A 458 188 N/A 582 246 1041 853 N/A
8 N/A 80 28 N/A 130 53 N/A 193 82 N/A 279 119 N/A 384 163 N/A 501 218 724 636 278 1144 937 408
10 N/A 84 31 N/A 138 56 N/A 207 90 N/A 299 131 N/A 409 177 606 538 236 776 686 302 1226 1010 454
15 N/A N/A 36 N/A 152 67 N/A 233 106 N/A 334 152 523 467 212 682 611 283 874 781 365 1374 1156 546
20 N/A N/A 41 N/A N/A 75 N/A 250 122 N/A 367 172 565 508 243 742 668 325 955 858 419 1513 1286 648
30 N/A N/A N/A N/A N/A N/A N/A 270 137 N/A 404 198 615 564 278 816 747 381 1062 969 496 1702 1473 749
50 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 620 328 879 831 461 1165 1089 606 1905 1692 922
100 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 348 N/A N/A 499 N/A N/A 669 2053 1921 1058
113
Combined Input Rating of the Appliances in Thousands of BTUH
Minimum Internal Area of Masonry Chimney Flue (in
2
)
H -
Vent
Height
(ft)
7528 38 50 6312 19
Table 3A - Vent Connector Capacity
Nat Nat Nat Nat Nat Nat Nat Nat
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
1 24 33 21 39 62 40 52 106 67 65 194 101 87 274 141 104 370 201 124 479 253 145 599 319
2 26 43 28 41 79 52 53 133 85 67 230 124 89 324 173 107 436 232 127 562 300 148 694 378
3 27 49 34 42 92 61 55 155 97 69 262 143 91 369 203 109 491 270 129 633 349 151 795 439
1 24 39 22 39 72 41 55 117 69 71 213 105 94 304 148 113 414 210 134 539 267 156 682 335
2 26 47 29 40 87 53 57 140 86 73 246 127 97 350 179 116 473 240 137 615 311 160 776 394
3 27 52 34 42 97 62 59 159 98 75 269 145 99 383 206 119 517 276 139 672 358 163 848 452
1 24 42 22 38 80 42 55 130 71 74 232 108 101 324 153 120 444 216 142 582 277 165 739 348
2 26 50 29 40 93 54 57 153 87 76 261 129 103 366 184 123 498 247 145 652 321 168 825 407
3 27 55 35 41 105 63 58 170 100 78 284 148 106 397 209 126 540 281 147 705 366 171 893 463
1 24 48 23 38 93 44 54 154 74 72 277 114 100 384 164 125 511 229 153 658 297 184 824 375
2 25 55 31 39 105 55 56 174 89 74 299 134 103 419 192 128 558 260 156 718 339 187 900 432
3 26 59 35 41 115 64 57 189 102 76 319 153 105 448 215 131 597 292 159 760 382 190 960 486
1 24 52 24 37 102 46 53 172 77 71 313 119 98 437 173 123 584 239 150 752 312 180 943 397
2 25 58 31 39 114 56 55 190 91 73 335 138 101 467 199 126 625 270 153 805 354 184 1011 452
3 26 63 35 40 123 65 57 204 104 75 353 157 104 493 222 129 661 301 156 851 396 187 1067 505
1 24 54 25 37 111 48 52 192 82 69 357 127 96 504 187 119 680 255 145 883 337 175 1115 432
2 25 60 32 38 122 58 54 208 95 72 376 145 99 531 209 122 715 287 149 928 378 179 1171 484
3 26 64 36 40 131 66 56 221 107 74 392 163 101 554 233 125 746 317 152 968 418 182 1220 535
1 23 51 25 36 116 51 51 209 89 67 405 143 92 582 213 115 798 294 140 1049 392 168 1334 506
2 24 59 32 37 127 61 53 225 102 70 421 161 95 604 235 118 827 326 143 1085 433 172 1379 558
3 26 64 36 39 135 69 55 237 115 72 435 180 98 624 260 121 854 357 147 1118 474 176 1421 611
1 23 46 24 35 108 50 49 208 92 65 428 155 88 640 237 109 907 334 134 1222 454 161 1589 596
2 24 53 31 37 120 60 51 224 105 67 444 174 92 660 260 113 933 368 138 1253 497 165 1626 651
3 25 59 35 38 130 68 53 237 118 69 458 193 94 679 285 116 956 399 141 1282 540 169 1661 705
15
20
30
Input Rating Limits in Thousands of BTUH
H -
Vent
Height
(ft)
Fan Assist Fan AssistFan AssistFan Assist Fan Assist
100
Common Vent Tables 3A and 3B - Capacity of an Interior Tile-Lined Masonry Chimney with Type B Double-Wall Connectors
Serving Two or More Category I Appliances
Fan AssistFan Assist
50
Fan Assist
6
8
R - Vent
Connector
Rise (ft)
10
9" Diameter 10" Diameter
NOTE: Category I appliance can be either Category I draft hood-equipped or fan-assisted type but must be approved for common venting.
5" Diameter 6" Diameter 7" Diameter 8" Diameter
Type B Double Wall Vent and Connector
3" Diameter 4" Diameter
Masonry Chimney Liner Dimensions with Circular Equivalents
Nominal Liner
Size (inches)
Inside Dimensions
of Liner (inches)
Inside Diameter or Equivalent
Diameter (inches)
Equivalent Area
(inches
2
)
4 x 8 2-1/2 x 6-1/2 4 12.2
5 19.6
6 28.3
7 38.3
8 x 8 6-3/4 x 6-3/4 7.4 42.7
8 50.3
8 x 12 6-1/2 x 10-1/2 9 63.6
10 78.5
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