Page 126 - 2018_IFGC

CHIMNEYS AND VENTS

TABLE 504.2(6) Number of Appliances Single
EXTERIOR MASONRY CHIMNEY
Appliance Type NAT
Appliance Vent Connection Type B double-wall connector
MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR
Internal area of chimney (square inches)
VENT HEIGHT
(feet) 12 19 28 38 50 63 78 113
37°F or Greater Local 99% Winter Design Temperature: 37°F or Greater
6 0 0 0 0 0 0 0 0
8 0 0 0 0 0 0 0 0
10 0 0 0 0 0 0 0 0
15 NA 0 0 0 0 0 0 0
20 NA NA 123 190 249 184 0 0
30 NA NA NA NA NA 393 334 0
50 NA NA NA NA NA NA NA 579
27 to 36°F Local 99% Winter Design Temperature: 27 to 36°F
6 0 0 68 116 156 180 212 266
8 0 0 82 127 167 187 214 263
10 0 51 97 141 183 201 225 265
15 NA NA NA NA 233 253 274 305
20 NA NA NA NA NA 307 330 362
30 NA NA NA NA NA 419 445 485
50 NA NA NA NA NA NA NA 763
17 to 26°F Local 99% Winter Design Temperature: 17 to 26°F
6 NA NA NA NA NA 215 259 349
8 NA NA NA NA 197 226 264 352
10 NA NA NA NA 214 245 278 358
15 NA NA NA NA NA 296 331 398
20 NA NA NA NA NA 352 387 457
30 NA NA NA NA NA NA 507 581
50 NA NA NA NA NA NA NA NA
5 to 16°F Local 99% Winter Design Temperature: 5 to 16°F
6 NA NA NA NA NA NA NA 416
8 NA NA NA NA NA NA 312 423
10 NA NA NA NA NA 289 331 430
15 NA NA NA NA NA NA 393 485
20 NA NA NA NA NA NA 450 547
30 NA NA NA NA NA NA NA 682
50 NA NA NA NA NA NA NA 972
-10 to 4°F Local 99% Winter Design Temperature: -10 to 4°F
6 NA NA NA NA NA NA NA 484
8 NA NA NA NA NA NA NA 494
10 NA NA NA NA NA NA NA 513
15 NA NA NA NA NA NA NA 586
20 NA NA NA NA NA NA NA 650
30 NA NA NA NA NA NA NA 805
50 NA NA NA NA NA NA NA 1,003
-11°F or Lower Local 99% Winter Design Temperature: -11°F or Lower
Not recommended for any vent configurations
For SI: °C = (°F - 32)/1.8, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 British thermal unit per hour = 0.2931 W.
Note: See Figure B-19 in Appendix B for a map showing local 99-percent winter design temperatures in the United States.

2018 INTERNATIONAL FUEL GAS CODE ® 113
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