VENTING TABLES CATEGORY I CENTRAL FURNACES

now exist for fan-assisted combustion system central furnaces.<br><br> Venting tables for these types of appliances are not contained in the National Fuel Gas Code (NFPA 54/ ANSI Z223.1-1988). All requirements contained in this booklet apply to both Category I drafthood equipped central furnaces as well as fan-assisted combustion system central furnaces. At no time should a venting system for a listed Category II, III, or IV central furnace be sized with these tables.<br><br> The National Fuel Gas Code (NFPA 54/ANSI Z223.1-1988) may also be used to size venting systems for drafthood equipped central furnaces. However, at this time, the National Fuel Gas Code does not include alternate sizing methods for fan-assisted combustion systems. There- fore, until engineering data is developed to allow alternate sizing methods for Category I fan-assisted central fur- naces, the enclosed venting tables must be used for fan-assisted combustion system central furnaces.<br><br> These tables apply to venting single appliances and common venting multiple appliances in both metal and masonry chimneys. The new venting tables were developed by Battelle under contract (GRI-5088-245-1728) to the Gas Research Institute (GRI). The computer program (VENT-II) developed by Battelle Columbus generated the vent- ing tables in this booklet and this procedure has been accepted by the American Gas Association Laboratories as an appropriate engineering methodology for determining venting requirements of Category I central furnaces.<br><br> For your information, the general venting requirements listed in this booklet are not intended to be used as complete installation instructions and represent only a partial list of venting considerations. For venting applications that fall outside the parameters of the new venting tables, refer to the furnace manufacturer 9s complete installation instructions, the speciRc vent manufacturer 9s complete installation instruc- tions, and state and local codes. GRI DISCLAIMER LEGAL NOTICE: This information is, in part, a result of work performed by Battelle under the sponsorship of the Gas Research Institute (GRI).<br><br> Neither GRI, members of GRI, nor any person acting on behalf of either: a. Makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of this information, or that the use of any apparatus, method, or process disclosed may not infringe privately owned rights; or b. Assumes any liability with respect to the use of, or for damages resulting from the use of, any information, apparatus, method, or process disclosed.<br><br> 1 I. INTRODUCTION This booklet contains the current deRnitions, instruc- tions, and tables necessary to vent todays modern Category I Gas Fired Appliance. A variety of deRni- tions of new terms describing today 9s gas appliances are included to supplement the actual venting tables which have been generated to correctly vent various combinations of Category I Appliances using Type B or single-wall metal vent connectors attached to Type B vents or masonry chimneys.<br><br> Tables are also included covering similar venting material combina- tions when applied to common venting arrangements of two or more appliances. Finally, a series of examples are presented demon- strating how the vent tables are used to size the vent connector and the vertical vent for a variety of typical applications. II.<br><br> DEFINITION OF TERMS cFan Assisted Combustion System d An appliance equipped with an integral mechanical means to either draw or force products of combustion through the com- bustion chamber and/or heat exchanger. cFAN Min d refers to the minimum appliance input rating of a Category I appli- ance with a fan-assisted com- bustion system that could be attached to the vent. cFAN Max d refers to the maximum appliance input rating of a Category I appli- ance with a fan-assisted com- bustion system that could be attached to the vent.<br><br> cNAT Max d refers to the maximum appliance input rating of a Category I appli- ance equipped with a drafthood that could be attached to the vent. There are no minimum appliance input ratings for drafthood- equipped appliances. cFAN+FAN d refers to the maximum combined input rating of two or more fan- assisted appliances attached to the common vent.<br><br> cFAN+NAT d refers to the maximum combined input rating of one or more fan- assisted appliance and one or more drafthood-equipped appli- ance attached to the common vent. cNAT+NAT d refers to the maximum combined input rating of two or more drafthood-equipped appliances attached to the common vent. cNR d means not recommended due to potential for condensate forma- tion and/or pressurization of the venting system.<br><br> cNA d means not applicable due to physical or geometric constraints. DraftHood A device built into an appliance, or made a part of the vent con- nector from an appliance, which is designed to (1) provide for the ready escape of the Sue gases from the appliance in the event of no draft, backdraft, or stoppage beyond the drafthood, (2) prevent a backdraft from entering the appliance, and (3) neutralize the effect of stack action of the chim- ney or gas vent upon the opera- tion of the appliance. Vent A passageway used to convey Sue gases from gas utilization equipment, or their vent connec- tors, to the outside atmosphere.<br><br> Vent Connector The pipe or duct which connects a fuel-gas burning appliance to a vent or chimney. Flue Collar That portion of an appliance designed for the attachment of a drafthood, vent connector, or venting system. Categorized Vent Diameter The minimum vent diameter per- missible for Category I appli- ances to maintain a nonpositive vent static pressure when tested in accordance with nationally rec- ognized standards.<br><br> VENTING REQUIREMENTS FOR CATEGORY I APPLIANCES 2 III. GENERAL VENTING REQUIREMENTS All requirements contained in this document apply to both Category I draft hood equipped and fan- assisted combustion appliances. At no time should a venting system for a listed Category II, III, or IV appli- ance be sized with these Tables.<br><br> The alternate sizing methods described in the National Fuel Gas Code (NFPA54/ANSI Z223.1-1988) may also be used to size the venting system for a drafthood equipped appliance. At this time, alternate sizing methods have not been developed for fan-assisted appli- ances. Therefore, until engineering data is devel- oped to allow alternate sizing methods for Category I fan-assisted appliances, the vent tables must be used.<br><br> 1) The venting tables included in this instruction apply to vents and chimneys internal to the structure below the roof line. Exterior chimneys or vents not enclosed by the structure or a chase below the roof line may experience con- tinuous condensation depending on locality. Consult local gas utility, appliance manufac- turer and/or local codes.<br><br> A chimney with one or more sides exposed to the outside of the struc- ture is considered to be an exterior chimney. A Type B or listed chimney lining system passing through an unused masonry chimney Sue is not considered to be exposed to the outdoors. 2) If the vent or connector size determined from the tables is smaller than the appliance draft- hood outlet or Sue collar, the smaller size may be used provided: a) The total vent height cH d is at least 10 FT.<br><br> b) Vents or connectors for appliance draft- hood outlets or Sue collars 12 inches in diameter or smaller are not reduced more than one table size (e.g. 12 inches to 10 inches is a one size reduction). c) Vents or connectors for appliance draft- hood or Sue collars above 12 inches in diameter are not reduced more than two table sizes (e.g.<br><br> 24 inches to 20 inches is a two size reduction). d) The maximum capacity listed in the tables for a fan-assisted appliance is reduced by 10% (0.90 x maximum capacity). e) The drafthood outlet is greater than 4 inches in diameter.<br><br> Do not connect a 3 inch diameter vent or connector to a 4 inch diameter drafthood outlet. This provision does not apply to fan-assisted appliances. 3) Single appliance venting conRgurations with zero lateral lengths, Tables 1 & 2, are assumed to have no elbows in the vent system.<br><br> For all other vent conRgurations, the vent system is assumed to have two 90 ° elbows. For each additional 90 ° elbow, or equivalent* beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity). * Two 45 ° elbows are equivalent to one 90 ° elbow.<br><br> 4) The common venting Tables 3, 4, 7, & 8 were generated using a maximum horizontal vent connector length of 1 1/2 feet (18 inches) for each inch of connector diameter as follows: The vent connector should be routed to the vent utilizing the shortest possible route. Con- nectors with longer horizontal lengths than those listed above are possible under the fol- lowing conditions: a) The maximum capacity (Fan Max. or Nat Max.) of the vent connector shall be reduced 10% for each additional multiple of the length listed above.<br><br> For example, the maximum length listed above for a 4 inch connector is 6 feet. With a connector length greater than 6 feet but not exceed- ing 12 feet, the maximum capacity must be reduced by 10% (0.90 x maximum vent connector capacity). With a connector length greater than 12 feet but not exceed- ing 18 feet, the maximum capacity must be reduced by 20% (0.80 x maximum vent capacity).<br><br> CONNECTOR DIAMETER (INCHES) MAXIMUM HORIZONTAL CONNECTOR LENGTH (FEET) 3 4 1/2 4 6 5 7 1/2 6 9 7 10 1/2 8 12 9 13 1/2 10 15 12 18 14 21 16 24 18 27 20 30 22 33 24 36 3 b) The minimum capacity (Fan Min.) shall be determined by referring to the correspond- ing single appliance table (Tables 1 and 2). In this case, for each appliance the entire vent connector and common vent from the appliance to the vent termination would be treated as a single appliance vent, as if the other appliances were not present. 5) If vent connectors are combined prior to enter- ing the common vent, the maximum common vent capacity listed in the common venting tables must be reduced by 10%, the equivalent of 1 (one) 90 ° elbow (0.90 x maximum common vent capacity).<br><br> See Figure 7. The horizontal length of the common vent connector manifold (L) should not exceed 1-1/2 feet (18 inches) for each inch of common vent connector manifold diameter. 6) If the common vertical vent is offset as shown in Figure 8, the maximum common vent capac- ity listed in the common venting tables should be reduced by 20%, the equivalent of 2 (two) 90 ° elbows (0.80 x maximum common vent capacity).<br><br> The horizontal length of the offset shall not exceed 1 1/2 feet for each inch of common vent diameter. 7) The common vent diameter must always be at least as large as the largest vent connector diameter. All interconnection Rttings must also be the same size as the common vent.<br><br> 8) Type B gas vents shall terminate above the roof surface with a listed cap or a listed roof assembly in accordance with the terms of their respective listings and the vent manufacturer 9s instructions. VENT CAPS 12Ý AND SMALLER Listed gas venting systems using listed vent caps 12Ý and smaller in size may terminate in accordance with the VENT TERMINATION TABLE. (SEE FIGURE 1) VENT CAPS LARGER THAN 12Ý Listed vent caps larger than 12Ý must be located at least 2 feet above the highest point and at least 2 feet higher than any portion of a building within a horizontal distance of 10 Feet.<br><br> (SEE FIGURE 2) 9) Use sea level input rating when determining maximum capacity for high altitude installation. Use actual input rating for determining mini- mum capacity for high altitude installation. GAS VENT TERMINATION TABLE *THIS REQUIREMENT COVERS MOST INSTALLATIONS ROOF PITCH MINIMUM HEIGHT FLAT TO 7/12 1.0 FEET* OVER 7/12 TO 8/12 1.5 FEET OVER 8/12 TO 9/12 2.0 FEET OVER 9/12 TO 10/12 2.5 FEET OVER 10/12 TO 11/12 3.25 FEET OVER 11/12 TO 12/12 4.0 FEET OVER 12/12 TO 14/12 5.0 FEET OVER 14/12 TO 16/12 6.0 FEET OVER 16/12 TO 18/12 7.0 FEET OVER 18/12 TO 20/12 7.5 FEET OVER 20/12 TO 21/12 8.0 FEET VERTICAL WALL LISTED CAP MINIMUM HEIGHT 8 2 MIN.<br><br> LOWEST DISCHARGE OPENING THE VENT TERMINATION SHOULD NOT BE LESS THAN 8 FT. FROM A VERTICAL WALL FIGURE 1 3 VENT CAPS 12 3 OR SMALLER 12 X ROOF PITCH IS X/12 2 2 MIN. 10 2 MIN.<br><br> FIGURE 2 3 VENT CAPS LARGER THAN 12 3 4 10) No portion of the venting system can extend into, or pass through any circulating air duct or plenum. 11) All vent pipe passing through Soors, walls, and ceilings must be installed with the listed clear- ance to combustible materials and be Rre stopped according to local codes. In the absence of local codes, refer to NFGC (Z223.1) 12) Vent connectors serving Category I appliances shall not be connected to any portion of mechanical draft systems operating under pos- itive pressure such as Category III or IV Vent- ing Systems.<br><br> 13) A Category I appliance must never be con- nected to a chimney that is servicing a solid fuel appliance. If a Rreplace chimney Sue is used to vent this appliance, the Rreplace open- ing must be permanently sealed. 14) A vent connector shall be supported without any dips or sags and shall slope a minimum of 1/4 inch per lineal foot of connector, back towards the appliance.<br><br> 15) Vent connectors shall be Rrmly attached to drafthood outlets or Sue collars by sheet-metal screws or other approved means, except vent connectors of listed Type B vent material which shall be assembled in accordance with the manufacturer 9s instructions. Joints between sections of single wall connector piping shall be fastened by sheet-metal screws or other approved means. 16) When the vent connector used for Category I appliances must be located in or pass through a crawl space or other area which may be cold, that portion of the vent connector shall be of listed double-wall Type B vent material or mate- rial having equivalent insulation qualities.<br><br> 17) The entire length of single wall metal vent con- nector shall be readily accessible for inspec- tion, cleaning, and replacement. 18) For appliances with more than one input rate, the minimum vent or connector (Fan Min) capac- ity determined from the tables shall be less than the lowest appliance input rating and the maxi- mum vent or connector (Fan or Nat Max.) capac- ity determined from the tables shall be greater than the highest appliance input rating. 19) For single appliance vents: a) If the vertical vent or tile lined chimney has a larger diameter or Sow area than the vent connector, use the vertical vent diam- eter to determine the minimum vent capacity and the vent connector diameter to determine the maximum vent capacity.<br><br> The Sow area of the vertical vent, however, shall not exceed 7 times the Sow area of the listed appliance categorized vent area, drafthood outlet area or Sue collar area unless designed in accordance with approved engineering methods. See Table 9 for calculated areas. b) For multiple appliance vents: The Sow area of the largest section of ver- tical vent or chimney shall not exceed 7 times the smallest listed appliance catego- rized vent area, Sue collar area, or draft hood outlet area unless designed in accor- dance with approved engineering meth- ods.<br><br> See Table for calculated areas. Maximum vent or tile lined chimney Sow area = x 7 * Drafthood outlet diameter, Sue collar diameter, or listed appli- ance categorized vent diameter. c) In no case, shall the vent connector be upsized more than 2 consecutive table size diameters over the size of the draft- hood outlet, Sue collar outlet, or listed appliance categorized vent.<br><br> Example : An appliance with a 4 inch diameter Sue outlet collar or drafthood outlet cannot be vented with a connector diameter larger than 6 inches. 20) Masonry chimneys used to vent Category I central furnaces must be either tile-lined or lined with a listed metal lining system or dedi- cated gas vent. Unlined masonry chimneys are prohibited.<br><br> (See Note 1). 21) A fan assisted furnace may be common vented into an existing masonry chimney provided: a. The chimney is currently serving at least one drafthood equipped appliance.<br><br> b. The vent connectors and chimney are sized in accordance with Tables 7 & 8. SINGLE APPLIANCE VENTING OF A FAN ASSISTED FURNACE INTO A TILE LINED, MASONRY CHIMNEY IS PROHIBITED.<br><br> THE CHIMNEY MUST FIRST BE LINED WITH EITHER TYPE B VENT SIZED IN ACCOR- DANCE WITH TABLES 1 OR 2 OR A LISTED SINGLE WALL, METAL LINING SYSTEM, SIZED IN ACCORDANCE WITH NOTE 22. TT D 7 ( ) 2 4 ------------------------- 5 22) Listed, corrugated metallic chimney liner sys- tems in masonry chimneys shall be sized by using Tables 1 or 2 for dedicated venting and Tables 3 or 4 for common venting with the max- imum capacity reduced by 20% (0.80 x maxi- mum capacity) and the minimum capacity as shown in the applicable table. Corrugated metal vent systems installed with bends or off- sets require additional reduction of the vent maximum capacity (See Note 6).<br><br> 23) For multiple units of gas utilization equipment all located on one Soor, available total height cH d is measured from the highest drafthood outlet or Sue collar up to the level of the cap or terminal. Connector rise cR d is measured from the drafthood outlet or Sue collar to the level where the vent gas streams come together. (Not applicable to multi-story).<br><br> 24) For multi-story installations, available total height for each segment of the system cH d is the vertical distance between the highest draft- hood outlet or Sue collar entering that segment and the centerline of the next higher intercon- nection tee (See Figure 13). 25) The size of the lowest connector and of the vertical vent leading to the lowest interconnec- tion of a multi-story system must be in accor- dance with Table 1 OR 2, for available total height cH d up to the lowest interconnection (See Figure 14). 26) Common vents in multi-story systems shall be type B when used in multi-story systems and have no offsets.<br><br> 27) Numbers followed by an asterisk (*) in Table 6, indicate the possibility of continuous condensa- tion, depending on locality. Consult appliance manufacturer, local serving gas supplier, and/or authority having jurisdiction. 28) In a single run of vent or vent connector, more than one diameter and type of pipe are permit- ted to be used, provided that all the sizes are permitted by the tables.<br><br> 29) If the desired vent height and connector rise and/or lateral are between the table entries, lin- ear interpolation is permitted for calculation of the permissible appliance input ratings. Extrap- olation beyond the table entries is not recom- mended. (See Example 7) 30) All combinations of pipe sizes, single-wall, and double-wall metal pipe are allowed within any connector run(s) or within the common vent provided ALL of the appropriate tables permit ALL of the desired sizes and types of pipe, as if they were used for the entire length of the sub- ject connector or vent.<br><br> If single-wall and Type B double-wall metal pipe are used for vent con- nectors, the common vent must be sized using Table 4. 31) Locate draft hood outlet or Sue collar of small- est input appliance closest to or under common vent. 32) When vent table permits more than one diam- eter of pipe to be used for a connector or vent, the smallest permitted diameter should be preferred.<br><br> TYPICAL VENTING APPLICATIONS FIGURE 3 Table 1 should be used when Type B vent is used for both the vent connector and the vertical vent. VENT VENT CONNECTOR D H L FIGURE 4 Table 2 should be used when a single-wall metal vent connector is attached toType B vertical vent. VENT VENT CONNECTOR D H L 6 FIGURE 5 Table 3 should be used when Type B vent connectors are attached to a Type B common vent.<br><br> TYPE B COMMON VENT APPLIANCE 1 APPLIANCE 2 D 2 D 1 H R 2 R 1 APPLIANCE 1 APPLIANCE 2 H R 1 R 2 D L Schematic Diagram showing a typical manifolded common vent section cL d of the vent connector. (See Note 5) cL d Less than or equal to 1.5 feet x D FIGURE 7 APPLIANCE 1 APPLIANCE 2 H R 1 R 2 D L Schematic Diagram showing offset in the common vent section of the vertical vent. (See Note 6) FIGURE 8 FIGURE 6 Table 4 should be used when single-wall metal vent connectors are attached to a Type B common vent.<br><br> TYPE B COMMON VENT APPLIANCE 1 APPLIANCE 2 D 2 D 1 H R 2 R 1 7 FIGURE 9 Table 5 shall be used when a Type B, double- wall vent connector is attached to a tile lined masonry chimney. TILE-LINED MASONRY CHIMNEY VENT CONNECTOR A L D H FIGURE 12 Table 8 shall be used when single-wall metal vent connectors are attached to a tile lined masonry chimney. TILE-LINED MASONRY CHIMNEY A D D H R R FIGURE 10 Table 6 shall be used when a single-wall metal vent connector is attached to a tile lined masonry chimney.<br><br> TILE-LINED MASONRY CHIMNEY VENT CONNECTOR A L D H FIGURE 11 Table 7 shall be used when Type B double-wall vent connectors are attached to a tile lined masonry chimney. TILE-LINED MASONRY CHIMNEY A D D H R R 8 VENT TABLES Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Serving a Single Category I Appliance TABLE 1 Height a Lateral H a aa L (ft) aa (ft) Vent and Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý Appliance Input Rating in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 6 0 2 4 6 0 13 21 25 78 51 49 46 46 36 34 32 0 18 30 36 152 97 94 91 86 67 64 61 0 27 39 47 251 157 153 149 141 105 103 100 0 32 50 59 375 232 227 223 205 157 153 149 0 44 66 78 524 321 316 310 285 217 211 205 0 53 79 93 698 425 419 413 370 285 279 273 0 63 93 110 897 543 536 530 470 370 362 354 8 0 2 5 8 0 12 23 28 84 57 53 49 50 40 38 35 0 16 32 39 165 109 103 98 94 75 71 66 0 25 42 51 276 178 171 164 155 120 115 109 0 28 53 64 415 263 255 247 235 180 173 165 0 42 70 84 583 365 356 347 320 247 237 227 0 50 83 99 780 483 473 463 415 322 313 303 0 60 99 117 1006 619 607 596 537 418 407 396 10 0 2 5 10 0 12 23 30 88 61 57 51 53 42 40 36 0 17 32 41 175 118 113 104 100 81 77 70 0 23 41 54 295 194 187 176 166 129 124 115 0 26 52 67 447 289 280 267 255 195 188 175 0 40 68 88 631 402 392 376 345 273 263 245 0 48 81 104 847 533 522 504 450 355 346 330 0 57 95 122 1096 684 671 651 585 457 446 427 15 0 2 5 10 15 0 11 22 29 35 94 69 65 59 53 58 48 45 41 37 0 15 30 40 48 191 136 130 121 112 112 93 87 82 76 0 20 39 51 61 327 226 219 206 195 187 150 142 135 128 0 22 49 64 76 502 339 330 315 301 285 225 217 208 198 0 38 64 84 98 716 475 463 445 429 390 316 300 288 275 0 45 76 99 115 970 633 620 600 580 525 414 403 386 373 0 53 90 116 134 1263 815 800 777 755 682 544 529 507 491 20 0 2 5 10 15 20 0 10 21 28 34 48 97 75 71 64 58 52 61 51 48 44 40 35 0 14 29 38 46 55 202 149 143 133 124 116 119 100 96 89 84 78 0 18 38 50 59 69 349 250 242 229 217 206 202 166 160 150 142 134 0 20 47 62 73 84 540 377 367 351 337 322 307 249 241 228 217 206 0 33 62 81 94 107 776 531 519 499 481 464 430 346 337 321 308 295 0 41 73 95 111 125 1057 711 697 675 654 634 575 470 460 443 427 410 0 50 86 112 129 145 1384 917 902 877 853 830 752 612 599 576 557 537 30 0 2 5 10 15 20 30 0 9 21 27 33 56 NR 100 81 77 70 64 58 NR 64 56 54 50 NR NR NR 0 13 28 37 44 53 73 213 166 160 150 141 132 113 128 112 108 102 96 90 NR 0 14 36 48 57 66 88 374 283 275 262 249 237 214 220 185 176 171 163 154 NR 0 18 45 59 70 80 104 587 432 421 405 389 374 346 336 280 273 261 249 237 219 0 27 58 77 90 102 131 853 613 600 580 560 542 507 475 394 385 371 357 343 321 0 33 69 91 105 119 149 1173 826 811 788 765 743 702 650 535 524 507 490 473 444 0 42 82 107 124 139 171 1548 1072 1055 1028 1002 977 929 855 700 688 668 648 628 594 50 0 2 5 10 15 20 30 0 8 20 26 59 NR NR 101 86 82 76 70 NR NR 67 61 NR NR NR NR NR 0 11 27 35 42 50 69 216 183 177 168 158 149 131 134 122 119 114 NR NR NR 0 14 35 45 54 63 84 397 320 312 299 287 275 250 232 206 200 190 180 169 NR 0 15 43 56 66 76 99 633 497 487 471 455 440 410 363 314 308 298 288 278 259 0 22 55 73 85 97 123 932 715 702 681 662 642 605 518 445 438 426 413 401 376 0 26 65 86 100 113 141 1297 975 960 935 911 888 844 708 615 605 589 572 556 522 0 33 77 101 117 131 161 1730 1276 1259 1230 1203 1176 1125 952 813 798 773 747 722 670 100 0 2 5 10 15 20 30 50 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 0 10 26 33 40 47 NR NR 218 194 189 182 174 166 NR NR NR NR NR NR NR NR NR NR 0 12 33 43 50 59 78 NR 407 354 347 335 321 311 290 NR NR NR NR NR NR NR NR NR 0 13 40 53 62 71 92 147 665 566 557 542 528 513 483 428 400 375 369 361 353 344 NR NR 0 18 52 68 80 90 115 180 997 831 820 801 782 763 726 651 560 510 504 493 482 471 449 405 0 21 60 80 93 105 131 197 1411 1155 1141 1118 1095 1073 1029 944 770 700 692 679 666 653 627 575 0 25 71 94 109 122 149 217 1908 1536 1519 1492 1465 1438 1387 1288 1040 935 926 910 895 880 849 787 9 VENT TABLES Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Serving a Single Category I Appliance TABLE 1 (Cont 9d) Height a Lateral H a aa L (ft) a a (ft) Vent and Connector Diameter - D (inches) 10Ý 12Ý 14Ý 16Ý 18Ý 20Ý 22Ý 24Ý Appliance Input Rating in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 6 0 2 4 6 0 75 110 128 1121 675 668 661 570 455 445 435 0 103 147 171 1645 982 975 967 850 650 640 630 0 138 191 219 2267 1346 1338 1330 1170 890 880 870 0 178 242 276 2983 1769 1761 1753 1530 1170 1160 1150 0 225 300 341 3802 2250 2242 2235 1960 1480 1475 1470 0 296 390 437 4721 2782 2774 2767 2430 1850 1835 1820 0 360 469 523 5737 3377 3370 3363 2950 2220 2215 2210 0 426 555 618 6853 4030 4023 4017 3520 2670 2660 2650 8 0 2 5 8 0 71 115 137 1261 770 758 746 660 515 503 490 0 98 154 180 1858 1124 1110 1097 970 745 733 720 0 130 199 231 2571 1543 1528 1514 1320 1020 1010 1000 0 168 251 289 3399 2030 2013 2000 1740 1340 1330 1320 0 212 311 354 4333 2584 2563 2552 2220 1700 1685 1670 0 278 398 450 5387 3196 3180 3163 2750 2110 2090 2070 0 336 476 537 6555 3882 3863 3850 3360 2560 2545 2530 0 401 562 630 7838 4634 4612 4602 4010 3050 3040 3030 10 0 2 5 10 0 68 112 142 1377 852 839 817 720 560 547 525 0 93 149 187 2036 1244 1229 1204 1060 850 829 795 0 124 192 238 2825 1713 1696 1669 1450 1130 1105 1080 0 161 243 298 3742 2256 2238 2209 1925 1480 1461 1430 0 202 300 364 4782 2868 2849 2818 2450 1890 1871 1840 0 264 382 459 5955 3556 3536 3504 3050 2340 2318 2280 0 319 458 546 7254 4322 4301 4268 3710 2840 2818 2780 0 378 540 641 8682 5153 5132 5099 4450 3390 3371 3340 15 0 2 5 10 15 0 63 105 135 155 1596 1019 1003 977 953 840 675 660 635 610 0 86 140 177 202 2380 1495 1476 1446 1418 1240 985 967 936 905 0 114 182 227 257 3323 2062 2041 2009 1976 1720 1350 1327 1289 1250 0 147 229 283 318 4423 2719 2696 2659 2623 2270 1770 1748 1712 1675 0 186 283 346 385 5678 3467 3442 3402 3363 2900 2260 2235 2193 2150 0 239 355 432 479 7099 4304 4278 4234 4192 3620 2800 2777 2739 2700 0 290 426 510 564 8665 5232 5204 5159 5115 4410 3410 3385 3343 3300 0 346 501 599 665 10393 6251 6222 6175 6129 5300 4080 4057 4019 3980 20 0 2 5 10 15 20 0 59 101 130 150 167 1756 1150 1133 1105 1078 1052 930 755 738 710 688 665 0 81 135 172 195 217 2637 1694 1674 1641 1609 1578 1350 1100 1079 1045 1018 990 0 107 174 220 248 273 3701 2343 2320 2282 2245 2210 1900 1520 1498 1460 1425 1390 0 139 219 273 306 335 4948 3097 3071 3029 2988 2948 2520 2000 1978 1940 1910 1880 0 175 270 334 372 404 6376 3955 3926 3880 3835 3791 3250 2570 2544 2500 2465 2430 0 220 337 413 459 495 7988 4916 4885 4835 4786 4737 4060 3200 3174 3130 3090 3050 0 269 403 489 541 585 9785 5983 5950 5896 5844 5792 4980 3910 3880 3830 3795 3760 0 321 475 573 631 689 11753 7154 7119 7063 7007 6953 6000 4700 4662 4600 4575 4550 30 0 2 5 10 15 20 30 0 54 96 125 143 160 195 1977 1351 1332 1301 1272 1243 1189 1060 865 851 829 807 784 745 0 74 127 164 187 207 246 3004 2004 1981 1944 1908 1873 1807 1550 1310 1289 1254 1220 1185 1130 0 98 164 209 237 260 305 4252 2786 2759 2716 2674 2633 2555 2170 1800 1775 1733 1692 1650 1585 0 127 206 259 292 319 369 5725 3696 3666 3617 3570 3523 3433 2920 2380 2350 2300 2250 2200 2130 0 159 252 316 354 384 440 7420 4734 4701 4647 4594 4542 4442 3770 3050 3020 2970 2920 2870 2785 0 199 312 386 431 467 540 9341 5900 5863 5803 5744 5686 5574 4750 3810 3783 3739 3695 3650 3565 0 241 373 456 507 548 635 11483 7194 7155 7090 7026 6964 6842 5850 4650 4622 4574 4527 4480 4375 0 285 439 535 590 639 739 13848 8617 8574 8505 8437 8370 8239 7060 5600 5552 5471 5391 5310 5225 50 0 2 5 10 15 20 30 0 41 90 118 136 151 183 2231 1620 1600 1567 1536 1505 1446 1195 1010 996 972 948 924 876 0 66 118 154 177 195 232 3441 2431 2406 2366 2327 2288 2214 1825 1513 1495 1466 1437 1408 1349 0 86 151 196 222 244 287 4934 3409 3380 3332 3285 3239 3150 2550 2125 2102 2064 2026 1987 1910 0 113 191 243 274 300 347 6711 4554 4520 4464 4409 4356 4253 3440 2840 2813 2767 2721 2675 2631 0 141 234 295 330 361 412 8774 5864 5826 5763 5701 5641 5523 4460 3670 3639 3585 3534 3481 3431 0 171 283 355 396 433 494 11129 7339 7295 7224 7155 7086 6953 5635 4630 4597 4542 4511 4479 4421 0 209 336 419 465 506 577 13767 8980 8933 8855 8779 8704 8557 6940 5695 5654 5585 5546 5506 5444 0 251 394 491 542 586 672 16694 10788 10737 10652 10570 10488 10328 8430 6860 6818 6749 6710 6670 6603 100 0 2 5 10 15 20 30 50 0 30 82 108 126 141 170 241 2491 1975 1955 1923 1892 1861 1802 1688 1310 1170 1159 1142 1124 1107 1071 1000 0 44 107 142 163 181 215 292 3925 3027 3002 2961 2920 2880 2803 2657 2050 1820 1803 1775 1747 1719 1663 1550 0 72 136 180 206 226 265 350 5729 4313 4282 4231 4182 4133 4037 3856 2950 2550 2531 2500 2469 2438 2375 2250 0 95 172 223 252 277 319 415 7914 5834 5797 5737 5678 5619 5505 5289 4050 3500 3475 3434 3392 3351 3267 3100 0 120 208 268 304 330 378 486 10485 7591 7548 7478 7409 7341 7209 6956 5300 4600 4566 4509 4451 4394 4279 4050 0 138 245 318 358 387 446 572 13454 9577 9528 9447 9367 9289 9136 8841 6700 5800 5769 5717 5665 5613 5509 5300 0 169 293 374 418 452 514 659 16817 11803 11748 11658 11569 11482 11310 10979 8600 7200 7162 7100 7037 6975 6850 6600 0 204 341 436 487 523 592 752 20578 14264 14204 14105 14007 13910 13720 13354 10300 8800 8756 8683 8610 8537 8391 8100 10 VENT TABLES Capacity of Type B Double-Wall Vents with Single-Wall Metal Connectors Serving a Single Category I Appliance TABLE 2 Height a Lateral H aa a L (ft) a a (ft) Vent and Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý 12Ý Appliance Input Rating in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 Min Max Max 6 0 2 4 6 38 39 NR NR 77 51 NR NR 45 36 33 31 59 60 74 83 151 96 92 89 85 66 63 60 85 85 102 114 249 156 152 147 140 104 102 99 126 123 146 163 373 231 225 220 204 156 152 148 165 159 187 207 522 320 313 307 284 213 208 203 211 201 237 263 695 423 416 409 369 284 277 271 267 251 295 327 894 541 533 526 469 368 360 352 371 347 409 449 1118 673 664 656 569 453 443 433 537 498 584 638 1639 979 971 962 849 648 638 627 8 0 2 5 8 37 39 NR NR 83 56 NR NR 50 39 37 33 58 59 77 90 164 108 102 95 93 75 69 64 83 83 107 122 273 176 168 161 154 119 114 107 123 121 151 175 412 261 252 243 234 179 171 163 161 155 193 223 580 363 352 342 319 246 235 225 206 197 245 280 777 482 470 458 414 321 311 300 258 246 305 344 1002 617 604 591 536 417 404 392 360 339 418 470 1257 768 754 740 658 513 500 486 521 486 598 665 1852 1120 1104 1089 967 743 730 715 10 0 2 5 10 37 39 52 NR 87 61 56 NR 53 41 39 34 57 59 76 97 174 117 111 100 99 80 76 68 82 82 105 132 293 193 185 171 165 128 122 112 120 119 148 188 444 287 277 261 254 194 186 171 158 153 190 237 628 400 388 369 344 272 261 241 202 193 241 296 844 531 518 497 449 354 344 325 253 242 299 363 1093 681 667 643 584 456 443 423 351 332 409 492 1373 849 834 808 718 559 544 520 507 475 584 688 2031 1242 1224 1194 1057 848 825 788 15 0 2 5 10 15 36 38 51 NR NR 93 69 63 NR NR 57 47 44 39 NR 56 57 75 95 NR 190 136 128 116 NR 111 93 86 79 72 80 80 102 128 158 325 225 216 201 186 186 149 140 131 124 116 115 144 182 220 499 337 326 308 290 283 224 217 203 192 153 148 182 228 272 713 473 459 438 418 388 314 298 284 269 195 187 231 284 334 966 631 616 592 568 523 413 400 381 367 244 232 287 349 404 1259 812 795 768 742 681 543 526 501 484 336 319 392 470 540 1591 1015 997 966 937 838 673 657 628 601 488 457 562 664 750 2374 1491 1469 1433 1399 1237 983 963 928 894 20 0 2 5 10 15 20 35 37 50 NR NR NR 96 74 68 NR NR NR 60 50 47 41 NR NR 54 56 73 93 NR NR 200 148 140 129 NR NR 118 99 94 86 80 NR 78 78 100 125 155 186 346 248 239 223 208 192 201 165 158 146 136 126 114 113 141 177 216 254 537 375 363 344 325 306 306 248 239 224 210 196 149 144 178 222 264 309 772 528 514 491 469 448 428 344 334 316 301 285 190 182 224 277 325 374 1053 708 692 666 640 616 573 468 457 437 419 400 238 227 279 339 393 448 1379 914 896 866 838 810 750 611 596 570 549 526 326 309 381 457 526 592 1751 1146 1126 1092 1060 1028 927 754 734 702 677 651 473 443 547 646 730 808 2631 1689 1665 1626 1587 1550 1346 1098 1074 1037 1005 973 30 0 2 5 10 15 20 30 34 37 49 NR NR NR NR 99 80 74 NR NR NR NR 63 56 52 NR NR NR NR 53 55 72 91 115 NR NR 211 164 157 144 131 NR NR 127 111 106 98 NR NR NR 76 76 98 122 151 181 NR 372 281 271 255 239 223 NR 219 183 173 168 157 NR NR 110 109 136 171 208 246 NR 584 429 417 397 377 357 NR 334 279 271 257 242 228 NR 144 139 171 213 255 298 389 849 610 595 570 547 524 477 472 392 382 367 349 333 305 184 175 215 265 312 360 461 1168 823 806 777 750 723 670 647 533 521 501 481 461 426 229 219 269 327 379 433 541 1542 1069 1049 1017 985 955 895 852 698 684 662 638 615 574 312 296 366 440 507 570 704 1971 1346 1324 1287 1251 1216 1147 1056 863 846 821 794 768 720 454 424 524 620 702 780 937 2996 1999 1971 1927 1884 1841 1759 1545 1308 1283 1243 1205 1166 1101 50 0 2 5 10 15 20 30 33 36 48 NR NR NR NR 99 84 80 NR NR NR NR 66 61 NR NR NR NR NR 51 53 70 89 112 NR NR 213 181 174 160 148 NR NR 133 121 117 NR NR NR NR 73 73 94 118 145 176 NR 394 318 308 292 275 257 NR 230 205 198 186 174 NR NR 105 104 131 162 199 236 315 629 495 482 461 441 420 376 361 312 305 292 280 267 NR 138 133 164 203 244 285 373 928 712 696 671 646 622 573 515 443 435 420 405 389 NR 176 168 204 253 299 345 442 1292 971 953 923 894 866 809 704 613 602 583 562 543 502 220 209 257 313 363 415 521 1724 1273 1252 1217 1183 1150 1086 948 811 795 765 736 708 649 295 280 347 418 481 544 674 2223 1615 1591 1551 1512 1473 1399 1189 1007 991 963 934 906 848 428 401 496 589 668 741 892 3432 2426 2396 2347 2299 2251 2159 1818 1509 1490 1455 1421 1387 1318 100 0 2 5 10 15 20 30 50 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 49 51 67 85 132 NR NR NR 214 192 186 175 162 NR NR NR NR NR NR NR NR NR NR NR 69 70 90 113 138 168 231 NR 403 351 342 324 310 295 264 NR NR NR NR NR NR NR NR NR 100 98 125 153 188 224 301 NR 659 563 551 532 511 487 448 NR 395 373 366 354 343 NR NR NR 131 125 156 191 230 270 355 540 991 828 813 789 764 739 685 584 555 508 501 486 473 458 NR NR 166 158 194 238 281 325 418 617 1404 1152 1134 1104 1075 1046 988 866 765 698 688 672 656 639 NR NR 207 196 240 293 342 391 491 711 1900 1532 1511 1477 1443 1410 1343 1205 1033 933 921 902 884 864 824 NR 273 259 322 389 447 507 631 895 2479 1970 1945 1905 1865 1825 1747 1591 1300 1168 1153 1133 1110 1087 1041 NR 395 371 460 547 618 690 834 1138 3912 3021 2990 2938 2888 2838 2739 2547 2042 1817 1796 1763 1730 1696 1627 1489 11 VENT TABLES Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Serving Two or more Category I Appliances TABLE 3 Vent Connector Capacity Common Vent Capacity Vent Height H (ft) Connector Rise R (ft) Vent Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Appliance Input Rating Limits in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 6 1 2 3 22 23 24 37 41 44 26 31 35 35 37 38 66 75 81 46 55 62 46 48 49 106 121 132 72 86 96 58 60 62 164 183 199 104 124 139 77 79 82 225 253 275 142 168 189 92 95 97 296 333 363 185 220 248 109 112 114 376 424 463 237 282 317 128 131 134 466 526 575 289 345 386 8 1 2 3 22 23 24 40 44 47 27 32 36 35 36 37 72 80 87 48 57 64 49 51 53 114 128 139 76 90 101 64 66 67 176 195 210 109 129 145 84 86 88 243 269 290 148 175 198 100 103 105 320 356 384 194 230 258 118 121 123 408 454 492 248 294 330 138 141 143 507 564 612 303 358 402 10 1 2 3 22 23 24 43 47 50 28 33 37 34 36 37 78 86 92 50 59 67 49 51 52 123 136 146 78 93 104 65 67 69 189 206 220 113 134 150 89 91 94 257 282 303 154 182 205 106 109 111 341 374 402 200 238 268 125 128 131 436 479 515 257 305 342 146 149 152 542 596 642 314 372 417 15 1 2 3 21 22 24 50 53 55 30 35 40 33 35 36 89 96 102 53 63 71 47 49 51 142 153 163 83 99 111 64 66 68 220 235 248 120 142 160 88 91 93 298 320 339 163 193 218 110 112 115 389 419 445 214 253 286 134 137 140 493 532 565 273 323 365 162 165 167 609 658 700 333 394 444 20 1 2 3 21 22 23 54 57 60 31 37 42 33 34 35 99 105 110 56 66 74 46 48 50 157 167 176 87 104 116 62 64 66 246 259 271 125 149 168 86 89 91 334 354 371 171 202 228 107 110 113 436 463 486 224 265 300 131 134 137 552 587 618 285 339 518 158 161 164 681 725 764 347 414 466 30 1 2 3 20 21 22 62 64 66 33 39 44 31 33 34 113 118 123 59 70 79 45 47 48 181 190 198 93 110 124 60 62 64 288 299 309 134 158 178 83 85 88 391 408 423 182 215 242 103 105 108 512 535 555 238 282 317 125 129 132 649 679 706 305 360 405 151 155 158 802 840 874 372 439 494 50 1 2 3 19 21 22 71 73 75 36 43 48 30 32 33 133 137 141 64 76 86 43 45 46 216 223 229 101 119 134 57 59 61 349 358 366 145 172 194 78 81 83 477 490 502 197 234 263 97 100 103 627 645 661 257 306 343 120 123 126 797 820 842 330 392 441 144 148 151 984 1014 1043 403 478 538 100 1 2 3 18 19 20 82 83 84 37 44 50 28 30 31 158 161 163 66 79 89 40 42 44 262 267 272 104 123 138 53 55 57 442 447 452 150 178 200 73 75 78 611 619 627 204 242 272 91 94 97 810 822 834 266 316 355 112 115 118 1038 1054 1069 341 405 455 135 139 142 1285 1306 1327 417 494 555 Vent Height H (ft) Common Vent Diameter - D (inches) 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Combined Appliance Input Rating in Thousands of Btu Per Hour 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 92 81 65 140 116 103 204 161 147 309 248 200 404 314 260 547 434 335 672 520 410 8 101 90 73 155 129 114 224 178 163 339 275 223 444 348 290 602 480 378 740 577 465 10 110 97 79 169 141 124 243 194 178 367 299 242 477 377 315 649 522 405 800 627 495 15 125 112 91 195 164 144 283 228 206 427 352 280 556 444 365 753 612 465 924 733 565 20 136 123 102 215 183 160 314 255 229 475 394 310 621 499 405 842 688 523 1035 826 640 30 152 138 118 244 210 185 361 297 266 547 459 360 720 585 470 979 808 605 1209 975 740 50 167 153 134 279 244 214 421 353 310 641 547 423 854 706 550 1164 977 705 1451 1188 860 100 175 163 NR 311 277 NR 489 421 NR 751 658 479 1025 873 625 1408 1215 800 1784 1502 975 12 VENT TABLES Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Serving two or more Category I Appliances TABLE 3 (cont 9d) Vent Connector Capacity Common Vent Capacity Vent Height H (ft) Connector Rise R (ft) Vent Connector Diameter - D (inches) 12Ý 14Ý 16Ý 18Ý 20Ý 22Ý 24Ý Appliance Input Rating Limits in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 6 2 4 6 174 180 NA 764 897 NA 496 616 NA 223 230 NA 1046 1231 NA 653 827 NA 281 287 NA 1371 1617 NA 853 1081 NA 346 352 NA 1772 2069 NA 1080 1370 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 8 2 4 6 186 192 198 822 952 1050 516 644 772 238 244 252 1126 1307 1445 696 884 1072 298 305 313 1478 1719 1902 910 1150 1390 365 372 380 1920 2211 2434 1150 1460 1770 NA 471 478 NA 2737 3018 NA 1800 2180 NA 560 568 NA 3319 3665 NA 2180 2640 NA 662 669 NA 3957 4373 NA 2590 3130 10 2 4 6 196 201 207 870 997 1095 536 664 792 249 256 263 1195 1371 1509 730 924 1118 311 318 325 1570 1804 1989 955 1205 1455 379 387 395 2049 2332 2556 1205 1535 1865 NA 486 494 NA 2887 3169 NA 1890 2290 NA 581 589 NA 3502 3849 NA 2280 2760 NA 686 694 NA 4175 4593 NA 2710 3270 15 2 4 6 214 221 228 967 1085 1181 568 712 856 272 279 286 1334 1499 1632 790 1006 1222 336 344 351 1760 1978 2157 1030 1320 1610 408 416 424 2317 2579 2796 1305 1665 2025 NA 523 533 NA 3197 3470 NA 2060 2510 NA 624 634 NA 3881 4216 NA 2490 3030 NA 734 743 NA 4631 5035 NA 2960 3600 20 2 4 6 223 230 237 1051 1162 1253 596 748 900 291 298 307 1443 1597 1726 840 1064 1288 357 365 373 1911 2116 2287 1095 1395 1695 430 438 450 2533 2778 2984 1385 1765 2145 NA 554 567 NA 3447 3708 NA 2180 2650 NA 661 671 NA 4190 4511 NA 2630 3190 NA 772 785 NA 5005 5392 NA 3130 3790 30 2 4 6 216 223 231 1217 1316 1400 632 792 952 286 294 303 1664 1802 1920 910 1160 1410 367 376 384 2183 2366 2524 1190 1510 1830 461 474 485 2891 3110 3299 1540 1920 2340 NA 619 632 NA 3840 4080 NA 2365 2875 NA 728 741 NA 4681 4976 NA 2860 3480 NA 847 860 NA 5606 5961 NA 3410 4150 50 2 4 6 206 213 221 1479 1561 1631 689 860 1031 273 281 290 2023 2139 2242 1007 1291 1575 350 359 369 2659 2814 2951 1315 1685 2055 435 447 461 3548 3730 3893 1665 2135 2605 NA 580 594 NA 4601 4808 NA 2633 3208 NA 709 724 NA 5569 5826 NA 3185 3885 NA 851 867 NA 6633 6943 NA 3790 4620 100 2 4 6 192 200 208 1923 1984 2035 712 888 1064 254 263 272 2644 2731 2811 1050 1346 1642 326 336 346 3490 3606 3714 1370 1760 2150 402 414 426 4707 4842 4968 1740 2220 2700 NA 523 539 NA 5982 6143 NA 2750 3350 NA 639 654 NA 7254 7453 NA 3330 4070 NA 769 786 NA 8650 8892 NA 3950 4810 Vent Height H (ft) Common Vent Diameter - D (inches) 12Ý 14Ý 16Ý 18Ý 20Ý 22Ý 24Ý Combined Appliance Input Rating in Thousands of Btu Per Hour 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 6 900 696 588 1284 990 815 1735 1336 1065 2253 1732 1345 2838 2180 1660 3488 2677 1970 4206 3226 2390 8 994 773 652 1423 1103 912 1927 1491 1190 2507 1936 1510 3162 2439 1860 3890 2998 2200 4695 3616 2680 10 1076 841 712 1542 1200 995 2093 1625 1300 2727 2113 1645 3444 2665 2030 4241 3278 2400 5123 3957 2920 15 1247 986 825 1794 1410 1158 2440 1910 1510 3184 2484 1910 4026 3133 2360 4971 3862 2790 6016 4670 3400 20 1405 1116 916 2006 1588 1290 2722 2147 1690 3561 2798 2140 4548 3552 2640 5573 4352 3120 6749 5261 3800 30 1658 1327 1025 2373 1892 1525 3220 2558 1990 4197 3326 2520 5303 4193 3110 6539 5157 3680 7940 6247 4480 50 2024 1640 1280 2911 2347 1863 3964 3183 2430 5184 4149 3075 6567 5240 3800 8116 6458 4500 9837 7813 5475 100 2569 2131 1670 3732 3076 2450 5125 4202 3200 6749 5509 4050 8597 6986 5000 10681 8648 5920 13004 10499 7200 13 VENT TABLES Capacity of Type B Double-Wall Vent with Single-Wall Connectors Serving Two or more Category I Appliances TABLE 4 Vent Connector Capacity Common Vent Capacity Vent Height H (ft) Connector Rise R (ft) Vent Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Appliance Input Rating Limits in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 6 1 2 3 NR NR NR NR NR NR 26 31 34 NR NR NR NR NR NR 46 55 62 NR NR 121 NR NR 131 71 85 95 NR 168 174 NR 182 198 102 123 138 207 215 222 223 251 273 140 167 188 262 271 279 293 331 361 183 219 247 325 334 344 373 422 462 234 281 316 447 458 468 463 524 574 286 344 385 15 1 2 3 NR NR NR NR NR NR 29 34 39 79 83 87 87 94 100 52 62 70 116 121 127 138 150 160 81 97 109 177 185 193 214 230 243 116 138 157 238 246 255 291 314 333 158 189 215 312 321 331 380 411 438 208 248 281 397 407 418 482 522 557 266 317 360 556 568 579 596 646 690 324 387 437 30 1 2 3 47 50 54 60 62 64 31 37 42 77 81 85 110 115 119 57 67 76 113 117 122 175 185 193 89 106 120 169 177 185 278 290 300 129 152 172 226 236 244 380 397 412 175 208 235 296 307 316 497 521 542 230 274 309 378 389 400 630 662 690 294 349 394 528 541 555 779 819 855 358 425 482 50 1 2 3 46 49 53 69 71 72 33 40 45 75 79 83 128 132 136 60 72 82 109 114 119 207 215 221 96 113 128 162 170 178 336 345 353 137 164 186 217 226 235 460 473 486 188 223 252 284 294 304 604 623 640 245 293 331 364 376 387 768 793 816 314 375 424 507 520 535 951 983 1013 384 458 518 Vent Height H (ft) Common Vent Diameter - D (inches) 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Combined Appliance Input Rating in Thousands of Btu Per Hour 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 89 78 64 136 113 100 200 158 144 304 244 196 398 310 257 541 429 332 665 515 407 8 98 87 71 151 126 112 218 173 159 331 269 218 436 342 285 592 473 373 730 569 460 10 106 94 76 163 137 120 237 189 174 357 292 236 467 369 309 638 512 398 787 617 487 15 121 108 88 189 159 140 275 221 200 416 343 274 544 434 357 738 599 456 905 718 553 20 131 118 98 208 177 155 305 247 223 463 383 302 606 487 395 824 673 512 1013 808 626 30 145 132 113 236 202 179 350 286 257 533 446 349 703 570 459 958 790 593 1183 952 723 50 159 145 128 268 233 204 406 337 296 622 529 410 833 686 535 1139 954 689 1418 1157 838 14 VENT TABLES Capacity of Masonry Chimney with Type B Double-Wall Vent Connectors Serving a Single Category I Appliance TABLE 5 Height Lateral H L (ft) (ft) Connector Diameter - D (inches) To be used with chimney areas within the size limits at bottom 3Ý4Ý5Ý6Ý7Ý8Ý9Ý10Ý12Ý Appliance Input Rating in Thousands of Btu Per Hour FAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NAT MinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax Max 62 5 NR NR NR NR 28 25* NR NR NR NR 52 49 NR NR NR NR 86 82 NR NR NR NR 130 117 NR NR NR NR 180 165 NR NR NR NR 247 231 NR NR NR NR 320 298 NR NR NR NR 401 376 NR NR NR NR 581 561 102 5 10 NR NR NR NR NR NR 31 28* 25* NR NR NR NR NR NR 61 57 50* NR NR NR NR NR NR 103 96 87 NR NR NR NR NR NR 162 148 139 NR NR NR NR NR NR 221 204 181 NR NR NR NR NR NR 298 277 263 NR NR NR NR NR NR 388 365 347 NR NR NR NR NR NR 491 466 444 NR NR NR NR NR NR 724 712 668 152 5 10 15 NR NR NR NR NR NR NR NR 35* 33* 28* NR NR NR NR NR NR NR NR NR 67 62 55* 48* NR NR NR NR NR NR NR NR 114 107 97 89* NR NR NR NR NR NR NR NR 179 164 153 141 NR NR NR NR NR NR NR NR 250 231 216 201 NR NR NR NR NR NR NR NR 336 313 296 281 NR NR NR NR NR NR NR NR 441 416 394 375 NR NR NR NR NR NR NR NR 562 533 567 485 NR NR NR NR NR NR NR NR 841 828 777 742 202 5 10 15 20 NR NR NR NR NR NR NR NR NR NR 38* 36* NR NR NR NR NR NR NR NR NR NR NR NR NR 74 68* 60* NR NR NR NR NR NR NR NR NR NR NR NR 124 116 107* 97* 83* NR NR NR NR NR NR NR NR NR NR 201 184 172 159 148* NR NR NR NR NR NR NR NR NR NR 274 254 237 220 206 NR NR NR NR NR NR NR NR NR NR 375 350 332 314 296 NR NR NR NR NR NR NR NR NR NR 491 463 440 418 397 NR NR NR NR NR NR NR NR NR NR 627 597 566 541 513 NR NR NR NR NR NR NR NR NR NR 953 933 879 840 807 302 5 10 15 20 30 NR NR NR NR NR NR NR NR NR NR NR NR 41* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 82* 76* 67* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 137 128* 115* 107* 91* NR NR NR NR NR NR NR NR NR NR NR NR NR 216 198 184* 171* 159* NR NR NR NR NR NR NR NR NR NR NR NR NR 303 281 263 243* 227* 188* NR NR NR NR NR NR NR NR NR NR NR NR 421 393 373 353 332 288* NR NR NR NR NR NR NR NR NR NR NR NR 558 526 500 476 450 416 NR NR NR NR NR NR NR NR NR NR NR NR 717 683 648 621 592 555 NR NR NR NR NR NR NR NR NR NR NR NR 1112 1094 1025 981 940 877 502 5 10 15 20 30 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 92* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 161* 151* 138* 127* NR NR NR NR NR NR NR NR NR NR NR NR NR NR 251* 230* 215* 199* 185* NR NR NR NR NR NR NR NR NR NR NR NR NR 351* 323* 304* 282* 264* NR NR NR NR NR NR NR NR NR NR NR NR NR 477 445 424* 400* 376* 327* NR NR NR NR NR NR NR NR NR NR NR NR 633 596 567 539* 511* 468* NR NR NR NR NR NR NR NR NR NR NR NR 812 774 733 702 669* 623* NR NR NR NR NR NR NR NR NR NR NR NR 1243 1225 1147 1099 1050 984 Minimum Internal Area of Chimney Square Inches 1219283850637895132 Maximum Internal Area of Chimney Square Inches 4988137198269352445550792 15 VENT TABLES Capacity of Masonry Chimney with Single-Wall Vent Connectors Serving a Single Category I Appliance TABLE 6 * See Note 27 Height a Lateral H aa a L (ft) aa (ft) Connector Diameter - D (inches) To be used with chimney areas within the size limits at bottom 3Ý4Ý5Ý6Ý7Ý8Ý9Ý10Ý12Ý Appliance Input Rating in Thousands of Btu Per Hour FAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NATFAN NAT MinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax MaxMinMax Max 62 5 NR NR NR NR 28 25* NR NR NR NR 52 48 NR NR NR NR 86 81 NR NR NR NR 130 116 NR NR NR NR 180 164 NR NR NR NR 247 230 NR NR NR NR 319 297 NR NR NR NR 400 375 NR NR NR NR 580 560 102 5 10 NR NR NR NR NR NR 31 28* 24* NR NR NR NR NR NR 61 56 49* NR NR NR NR NR NR 102 95 86 NR NR NR NR NR NR 161 147 137 NR NR NR NR NR NR 220 203 189 NR NR NR NR NR NR 297 276 261 NR NR NR NR NR NR 387 364 345 NR NR NR NR NR NR 490 465 441 NR NR NR NR NR NR 722 710 665 152 5 10 15 NR NR NR NR NR NR NR NR 35* 32* 27* NR NR NR NR NR NR NR NR NR 67 61 54* 46* NR NR NR NR NR NR NR NR 113 106 96 87* NR NR NR NR NR NR NR NR 178 163 151 138 NR NR NR NR NR NR NR NR 249 230 214 198 NR NR NR NR NR NR NR NR 335 312 294 278 NR NR NR NR NR NR NR NR 440 414 392 372 NR NR NR NR NR NR NR NR 560 531 504 481 NR NR NR NR NR NR NR NR 840 825 774 738 202 5 10 15 20 NR NR NR NR NR NR NR NR NR NR 38* 35* NR NR NR NR NR NR NR NR NR NR NR NR NR 73 67* 59* NR NR NR NR NR NR NR NR NR NR NR NR 123 115 105* 95* 80* NR NR NR NR NR NR NR NR NR NR 200 183 170 156 144* NR NR NR NR NR NR NR NR NR NR 273 252 235 217 202 NR NR NR NR NR NR NR NR NR NR 374 348 330 311 292 NR NR NR NR NR NR NR NR NR NR 490 461 437 414 392 NR NR NR NR NR NR NR NR NR NR 625 594 562 536 510 NR NR NR NR NR NR NR NR NR NR 950 930 875 835 800 302 5 10 15 20 30 NR NR NR NR NR NR NR NR NR NR NR NR 41* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 81* 75* 66* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 136 127* 113* 105* 88* NR NR NR NR NR NR NR NR NR NR NR NR NR 215 196 182* 168* 155* NR NR NR NR NR NR NR NR NR NR NR NR NR 302 279 260 240* 223* 182* NR NR NR NR NR NR NR NR NR NR NR NR 420 391 370 349 327 281* NR NR NR NR NR NR NR NR NR NR NR NR 556 524 496 471 445 408 NR NR NR NR NR NR NR NR NR NR NR NR 715 680 644 615 585 544 NR NR NR NR NR NR NR NR NR NR NR NR 1110 1090 1020 975 932 865 502 5 10 15 20 30 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 91* NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 160* 149* 136* 124* NR NR NR NR NR NR NR NR NR NR NR NR NR NR 250* 228* 212* 195* 180* NR NR NR NR NR NR NR NR NR NR NR NR NR 350* 321* 301* 278* 258* NR NR NR NR NR NR NR NR NR NR NR NR NR 475 442 420* 395* 370* 318* NR NR NR NR NR NR NR NR NR NR NR NR 631 593 562 533* 504* 458* NR NR NR NR NR NR NR NR NR NR NR NR 810 770 728 695 660* 610* NR NR NR NR NR NR NR NR NR NR NR NR 1240 1220 1140 1090 1040 970 Minimum Internal Area of Chimney Square Inches 1219283850637895132 Maximum Internal Area of Chimney Square Inches 4988137198269352445550792 16 VENT TABLES Capacity of Masonry Chimney with Type B Double-Wall Connectors Serving two or more Category I Appliances TABLE 7 Vent Connector Capacity Common Vent Capacity Vent Height H (ft) Connector Rise R (ft) Vent Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Appliance Input Rating Limits in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 6 1 2 3 24 26 27 NR 43 49 21 28 34 39 41 42 62 79 92 40 52 61 52 53 55 106 133 155 67 85 97 65 67 69 194 230 262 101 124 143 87 89 91 274 324 369 141 173 203 104 107 109 370 436 491 201 232 270 124 127 129 479 562 633 253 330 349 145 148 151 599 694 795 319 378 439 15 1 2 3 24 25 26 48 55 59 23 31 35 38 39 41 93 105 115 44 55 64 54 56 57 154 174 189 74 89 102 72 74 76 277 299 319 114 134 153 100 103 105 384 419 448 174 192 215 125 128 131 511 558 597 229 260 292 153 156 159 658 718 760 297 339 382 184 187 190 824 900 960 375 432 486 30 1 2 3 24 25 26 54 60 64 25 32 36 37 38 40 111 122 131 48 58 66 52 54 56 192 208 221 82 95 107 69 72 74 357 376 392 127 145 163 96 99 101 504 531 554 187 209 233 119 122 125 680 715 746 255 287 317 145 149 152 883 928 968 337 378 418 175 179 182 1115 1171 1220 432 484 535 50 1 2 3 23 24 26 52 59 64 26 31 37 36 37 39 116 127 135 49 58 66 51 53 55 209 225 237 82 96 108 67 70 72 405 421 435 133 152 170 92 95 98 582 604 624 198 222 247 115 118 121 798 827 854 271 304 334 140 143 147 1049 1085 1118 362 400 439 168 172 176 1334 1379 1421 462 510 558 Vent Height H (ft) Minimum Internal Area of Chimney, Square Inches 12 19 28 38 50 63 78 113 Combined Appliance Input Rating in Thousands of Btu Per Hour 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 NR 74 25 NR 119 46 NR 178 71 NR 257 103 NR 351 143 NR 458 188 NR 582 246 NR 853 NR 8 NR 80 28 NR 130 53 NR 193 82 NR 279 119 NR 384 163 NR 501 218 NR 636 278 NR 937 408 10 NR 84 31 NR 138 56 NR 207 90 NR 299 131 NR 409 177 NR 538 236 NR 686 302 NR 1010 454 15 NR 90 36 NR 152 67 NR 233 106 NR 334 152 NR 467 212 NR 611 283 NR 781 365 NR 1156 546 20 NR 92 41 NR 159 75 NR 250 122 NR 368 172 NR 508 243 NR 668 325 NR 858 419 NR 1286 648 30 NR NR NR NR NR NR NR 270 137 NR 404 198 NR 564 278 NR 747 381 NR 969 496 NR 1473 749 50 NR NR NR NR NR NR NR NR NR NR NR NR NR 620 328 NR 831 461 NR 1089 606 NR 1692 922 17 VENT TABLES Capacity of Masonry Chimney with Single-Wall Connectors Serving two or more Category I Appliances TABLE 8 Vent Connector Capacity Common Vent Capacity Vent Height H (ft) Connector Rise R (ft) Vent Connector Diameter - D (inches) 3Ý 4Ý 5Ý 6Ý 7Ý 8Ý 9Ý 10Ý Appliance Input Rating Limits in Thousands of Btu Per Hour FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT FAN 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 6 1 2 3 NR NR NR NR NR NR 21 28 34 NR NR NR NR NR NR 39 52 61 NR NR 134 NR NR 153 66 84 97 179 186 193 191 227 258 100 123 142 231 239 247 271 321 365 140 172 202 292 301 309 366 432 491 200 231 269 362 373 381 474 557 634 252 299 348 499 509 519 594 696 793 283 331 375 15 1 2 3 NR NR NR NR NR NR 23 30 34 NR 92 96 NR 103 112 43 54 63 129 135 141 151 170 185 73 88 101 199 207 215 271 295 315 112 132 151 268 277 286 376 411 439 171 189 213 349 359 368 502 548 586 225 256 289 445 456 466 646 706 755 291 334 378 623 634 646 808 884 945 360 402 437 30 1 2 3 NR NR NR NR NR NR 24 31 35 86 91 95 108 119 127 47 57 65 126 132 138 187 203 216 80 93 105 193 201 209 347 366 381 124 142 160 259 269 277 492 518 540 183 205 229 338 348 358 665 699 729 250 282 312 430 442 452 864 908 946 330 372 412 600 613 626 1089 1145 1193 455 490 521 50 1 2 3 NR NR NR NR NR NR 25 31 35 85 89 94 113 123 131 48 57 65 124 130 136 204 218 231 80 94 106 188 196 205 392 408 422 130 149 167 252 262 271 567 588 607 194 218 243 328 339 349 778 806 831 265 298 328 417 429 440 1022 1058 1090 355 393 431 582 596 610 1302 1346 1386 537 567 595 Vent Height H (ft) Minimum Internal Area of Chimney, Square Inches 12 19 28 38 50 63 78 113 Combined Appliance Input Rating in Thousands of Btu Per Hour 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 NR 73 25 NR 118 45 NR 176 71 NR 255 102 NR 348 142 NR 455 187 NR 579 245 NR 846 NR 8 NR 79 28 NR 128 52 NR 190 81 NR 276 118 NR 380 162 NR 497 217 NR 633 277 NR 928 405 10 NR 83 31 NR 136 56 NR 205 89 NR 295 129 NR 405 175 NR 532 234 NR 680 300 NR 1000 450 15 NR 88 36 NR 149 66 NR 230 105 NR 335 150 NR 460 210 NR 602 280 NR 772 360 NR 1139 540 20 NR 90 40 NR 157 74 NR 247 120 NR 362 170 NR 503 240 NR 661 321 NR 849 415 NR 1264 640 30 NR NR NR NR NR NR NR 266 135 NR 398 195 NR 558 275 NR 739 377 NR 957 490 NR 1447 740 50 NR NR NR NR NR NR NR NR NR NR NR NR NR 612 325 NR 821 456 NR 1076 600 NR 1672 910 18 TABLE 9 MASONRY CHIMNEY LINER DIMENSIONS WITH CIRCULAR EQUIVALENTS When liner sizes differ dimensionally from those shown in Table 9 equivalent diameters may be determined from published tables for square and rectangular ducts of equivalent carrying capacity or by other engineering methods. NOMINAL LINER SIZE INCHES INSIDE DIMENSIONS IN LINER INCHES INSIDE DIA.<br><br> OR EQUIVALENT DIA. INCHES EQUIVALENT AREA SQ. INCHES 4 x 8 2 1/2 x 6 1/2 4 5 6 7 12.2 19.6 28.3 38.3 8 x 8 6 3/4 x 6 3/4 7.4 8 42.7 50.3 8 x 12 6 1/2 x 10 1/2 9 10 63.6 78.5 12 x 12 9 3/4 x 9 3/4 10.4 11 83.3 95 12 x 16 9 1/2 x 13 1/2 11.8 12 14 107.5 113 153.9 16 x 16 13 1/4 x 13 1/4 14.5 15 162.9 176.7 16 x 20 13 x 17 16.2 18 206.1 254.4 20 x 20 16 3/4 x 16 3/4 18.2 20 260.2 314.1 20 x 24 16 1/2 x 20 1/2 20.1 22 314.2 380.1 24 x 24 20 1/4 x 20 1/4 22.1 24 380.1 452.3 24 x 28 20 1/2 x 24 1/4 24.1 456.2 28 x 28 24 1/4 x 24 1/4 26.4 27 543.3 572.5 30 x 30 25 1/2 x 25 1/2 27.9 30 607 706.8 30 x 36 25 1/2 x 31 1/2 30.9 33 749.9 855.3 36 x 36 31 1/2 x 31 1/2 34.4 36 929.4 1017.9 19 Example 1: Single Draft-Hood-Equipped Appliance Suppose that an installer has a 120,000 Btu/hr input appli- ance with a 5 inch diameter draft hood outlet that needs to be vented into a 10 foot high Type B vent system.<br><br> What size vent should be used assuming (a) a 5-Ft lateral sin- gle-wall metal vent connector is used with two 90 ° elbows, (b) a 5-Ft lateral single-wall metal vent connector is used with three 90 ° elbows in the vent system? Solution Table 2 should be used to solve this problem because sin- gle-wall metal vent connectors are being used with a Type B vent: Refer to Figure 4 of Typical Applications. (a) Read down the Rrst column in Table 2 until the row associated with a 10-Ft height and a 5-Ft lateral is found.<br><br> Read across this row until a vent capacity greater than 120,000 Btu/hr is located in the shaded columns labeled cNAT Max d for draft-hood- equipped appliances. In this case, a 5 inch diameter vent has a capacity of 122,000 Btu/hr and may be used for this application. (b) If three 90 ° elbows are used in the vent system, then the maximum vent capacity listed in the tables must be reduced by 10 percent (see Note 3).<br><br> This implies that the 5 inch diameter vent has an adjusted capacity of only 110,000 Btu/hr. In this case, the vent system must be increased to 6 inches in diameter. See calculations below: 122,000 x .90 = 110,000 for 5Ý Vent From Table 2 4Select 6Ý Vent 186,000 x .90 = 167,000; This is greater than the required 120,000, therefore use a 6Ý Vent and connector when three elbows are used.<br><br> 10 2 5 2 EXAMPLE 1 DRAFT HOOD EQUIPPED APPLIANCE 120,000 BTUH INPUT B-VENT ELBOW SINGLE WALL Example 2: Single Fan-Assisted Appliance Suppose an installer has an 80,000 Btu/hr input fan- assisted appliance that must be installed using 10 feet of lateral connector attached to a 30-Ft high Type B vent. Two 90 ° elbows are needed for the installation. Can a sin- gle-wall metal vent connector be used for this application?<br><br> Solution Table 2 refers to the use of single-wall metal vent connec- tors with Type B vent. In the Rrst column Rnd the row asso- ciated with a 30-Ft height and a 10-Ft lateral. Read across this row, looking at the cFAN Min d and cFAN Max d columns, to Rnd that a 3 inch diameter single-wall metal connector vent is not recommended.<br><br> Moving to the next larger size single wall connector (4Ý) we Rnd that a 4 inch diameter single-wall metal connector has a recommended minimum vent capacity of 91,000 Btu/hr and a recommended maxi- mum vent capacity of 144,000 Btu/hr. The 80,000 Btu/hr fan-assisted appliance is outside this range, so we con- clude that a single-wall metal vent connector cannot be used to vent this appliance using 10 feet of lateral for the connector. However, we see that if the 80,000 Btu/hr input appliance could be moved to within 5 feet of the vertical vent, then a 4 inch single-wall metal connector could be used to vent the appliance.<br><br> Table 2 shows the acceptable range of vent capacities for a 4 inch vent with 5 feet of lateral to be between 72,000 Btu/hr and 157,000 Btu/hr. If the appliance cannot be moved closer to the vertical vent, then Type B vent could be used as the connector material. In this case, Table 1 shows that for a 30-Ft high vent with 10 feet of lateral, the acceptable range of vent capacities for a 4 inch diameter vent attached to a fan-assisted appliance are between 37,000 Btu/hr and 150,000 Btu/hr.<br><br> 30 2 10 2 LATERAL EXAMPLE 2 FAN ASSISTED APPLIANCE 80,000 BTUH INPUT EXAMPLES USING SINGLE APPLIANCE VENTING TABLES 20 Example 3: Common Venting Two Draft-Hood Appliances Suppose a 35,000 Btu/hr water heater is to be common vented with a 150,000 Btu/hr furnace using a common vent with a total height of 30 feet. The connector rise is 2 feet for the water heater and 3 feet for the furnace. Assume single-wall metal connectors will be used with Type B vent.<br><br> What size connectors and combined vent should be used in this installation? Solution 4(Table 4 applies in this example) Table 4 should be used to size single-wall metal vent con- nectors attached to Type B vertical vent. In the vent con- nector capacity Table 4, Rnd the row associated with a 30- Ft vent height.<br><br> For a 2-Ft rise on the vent connector for the water heater, read the shaded columns for draft-hood- equipped appliances to Rnd that a 3 inch diameter vent connector has a capacity of 37,000 Btu/hr. Therefore, a 3 inch single-wall metal vent connector may be used with the water heater. For a draft-hood-equipped furnace with a 3-Ft rise, read across the appropriate row to Rnd that a 5 inch diameter vent connector has a maximum capacity of 120,000 Btu/hr (which is too small for the fur- nace) and a 6 inch diameter vent connector has a<br><br>

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