Supersedes: AD3V (991) AD3V (1294)

Transcription

1 APPLICATION DATA VENTING TABLES CATEGORY I, CENTRAL FURNACES Supersedes: AD3V (991) AD3V (1294) SIZING OF VENTING SYSTEMS SERVING APPLIANCES EQUIPPED WITH DRAFT HOODS, CATEGORY I APPLIANCES AND APPLIANCES LISTED FOR USE WITH TYPE B VENTS CONTENTS: Guidelines for Single Appliance Vents Single Appliance Venting Figures and Tables Guidelines for Multi-Appliance Vents Multi-Appliance Venting Figures and Tables Reference for Masonry Chimney Liner Dimensions...13 Manifolded & Offset Common Venting...14 Multistory Venting Design Procedures GENERAL These instructions, along with the furnace installation instructions should be read carefully and completely before installing this furnace. The vent system should be sized with the assistance of these venting tables where they are applicable. When an existing furnace is removed or replaced in a venting system, the venting system may not be properly sized to vent the attached appliances. An improperly sized venting system could result in the formation of condensate and leakage or spillage of combustion products. This appliance may be common vented and installed in multistory vent systems according to the guidelines contained in this instruction. Fan-assisted combustion system Category I furnaces shall not be vented into single wall metal vents. Category I furnaces must be vented vertically or nearly vertically, unless equipped with a listed mechanical venter. Vent connectors serving Category I and Category II furnaces shall not be connected into any portion of mechanical draft systems operating under positive pressure. The furnace shall be connected to a factory built chimney or vent complying with a recognized standard, or a masonry or concrete chimney lined with a lining material acceptable to the authority having jurisdiction. Venting into an unlined masonry chimnney or concrete chimney is prohibited. These venting tables and guidelines are applicable for all Category I appliances (drafthood equipped central furnaces and fan assisted combustion system central furnaces) vented into a dedicated vent or common vent with other Category I appliances. These tables and guidelines should be used for venting into a chimney, as allowed. Along with the venting tables, these instructions include definitions or terms and examples demonstrating how to use the vent tables for a variety of applications. Where the vent pipe will be exposed in an unconditioned or cool location, (i.e., attic crawl space, etc.) only double wall B-vent pipe should be used. When reference in this publication is made to the National Fuel Gas Code NFPA No. 54/ANSI Z (latest edition), note this applies only to installations inside the United States. All Canadian installations must be made in accordance with the CAN/CGA-B149.1M91 and CAN/CGA-B149.2-M91 installation codes. All venting systems shall be made in accordance with one of the above codes and all other authorities having jurisdiction. DEFINITIONS The following definitions apply to tables in these instructions: FAN ASSISTED COMBUSTION SYSTEM - An appliance equipped with an integral mechanical means to either draw or force products of combustion through the combustion chamber and/or heat exchanger. FAN MIN. - The minimum appliance input rating of a Category I appliance with a fan-assisted combustion system that could be attached to the vent. FAN MAX. - The maximum appliance input rating of a Category I appliance with a fan-assisted combustion system that could be attached to the vent. NAT MAX. - The maximum input rating of a Category I appliance equipped with a draft hood that could be attached to the vent. There are no minimum appliance input ratings for draft hood-equipped appliances. FAN + FAN - The maximum combined appliance input rating of two or more fan-assisted appliances attached to the common vent. FAN + NAT - The maximum combined appliances input rating of one or more fan-assisted appliances and one or more draft hood-equipped appliances attached to the common vent. NAT + NAT - The maximum combined input rating of two or more draft hood-equipped appliances attached to the common vent. NR - Vent configuration is not recommended due to potential for condensate formation and/or pressurization of the venting system. NA - Vent configuration is not applicable due to physical or geometric constraints. SINGLE APPLIANCE Notes for Single Appliance Vents (See Tables J-1 to J-5) 1. If the smaller size determined from the tables is smaller than the appliance draft hood outlet or flue collar, the smaller size shall be permitted to be used, provided: (a) The total vent height ("I") is at least 10 feet (3.05 m).

2 (b) Vents for appliance draft hood outlets or flue collars 12 inches (305 mm) in diameter or smaller are not reduced more than two table sizes. (c) Vents for appliance draft hood outlets or flue collars above 12 inches (305 mm) in diameter are not reduced more than two table sizes. (d) The maximum capacity listed in the tables for a fanassisted appliance is reduced by 10 percent (0.90 x maximum table capacity). (e) The draft hood outlet is greater than 4 inches in diameter. Do not connect a 3-inch diameter vent to a 4-inch diameter draft hood outlet. This provision ("e") shall not apply to fan-assisted appliances. 2. Single appliance venting configurations with zero ("0") lateral lengths in Tables J-1, J-2 and J-5 shall have no elbows in the venting system. For vent configurations with lateral lengths, the venting tables include allowances for two 90-degree (1.57 rad) elbows. For each additional 90-degree (1.57 rad) elbow, or equivalent beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum table capacity). NOTE: Two 45-degree (0.79 rad) elbows are equivalent to one 90-degree (1.57 rad) elbow. 3. Zero ("0") lateral ("L") shall apply only to a straight verticalvent attachment to a top outlet draft hood or flue collar. 4. Sea-level input ratings shall be used when determining maximum capacity for high-altitude installation. Actual input (derated for altitude) shall be used to determine minimum capacity for high altitude installation. 5. Numbers followed by an asterisk (*) in Tables J-3, J-4 and J-5 indicate the possibility of condensation, depending on locality. Consult local serving gas supplier or local codes. 6. For appliances with more than one input rate, the minimum vent capacity determined from the tables shall be greater then the highest appliance input rating. 7. Listed corrugated metallic chimney-liner systems in masonry chimneys shall be sized by using Tables J-1 or J-2 for Type B vents with the maximum capacity reduced by 20 percent (0.80 maximum table capacity) and the minimum capacity as shown in Tables J-1 and J-2. Corrugated metal venting systems installed with bends or offsets shall have their maximum capacity reduced. (See Note 2). 8. If the vertical vent has a larger diameter than the vent connector, use the vertical vent-connector diameter to determine the minimum vent capacity and the connector diameter to determine the maximum vent capacity. The flow of the vertical vent shall not exceed seven times the flow area of the listed appliance categorized vent area, flue collar area, or draft hood outlet area, unless designated in accordance with approved engineering methods. 9. The tables listed in this Part shall be used for chimneys and vents not exposed to the outdoors below the roof line. Exterior chimneys or vents exposed to the outdoors below the roof line may experience continuous condensation, depending upon the locality. Consult local serving gas suppliers, or the authority having jurisdiction. A Type B vent or listed chimney-lining system passing through an otherwise unused masonry chimney flue shall be considered to be an interior-vent system. 10. Vent connectors shall not be sized upward more then two sizes greater then the appliance categorized vent diameter, flue collar diameter, or draft hood-outlet diameter. 11. In a single run of vent or vent connector, more than one diameter and type shall be permitted to be used provided that all the sizes and type are permitted by the tables. 12. Interpolation shall be permitted in calculating capacities for vent dimensions which fall between table entries. 13. Extrapolation beyond the table entries shall not be permitted. 2 Unitary Products Group

3 FIGURE J-1 Table J-1 shall be used when Type B Double-Wall Vent Pipe is used for both the vent connector and the vent. NOTE: The appliance may be either Category I Draft Hood-equipped or Fan-assisted type. Table J-1 Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Servicing a Single Category I Appliance Vent and Connector Diameter - D 3" 4" 5" 6" 7" Height Lateral Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR Unitary Products Group 3

4 FIGURE J-2 Table J-2 shall be used when a Single Wall Metal Vent Connector is attached to a Type B Double-Wall Vent NOTE: The appliance may be either Category I Draft Hood-equipped or Fan-assisted type. Table J-2 Capacity of Type B Double-Wall Vents with Single-Wall Metal Connectors Servicing a Single Category I Appliance Vent and Connector Diameter - D 3" 4" 5" 6" 7" Height Lateral Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 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 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 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR 4 Unitary Products Group

5 FIGURE J-3 Table J-3 shall be used when a Type B Double-Wall Vent Connector is attached to a Tile-Lined Masonry Chimney. NOTE: The appliance may be either Category I Draft Hood-equipped or Fan-assisted type. NOTE: "A" is the equivalent cross sectional area of the Tile Liner. Table J-3 Capacity of Masonry Chimney Type B Double-Wall Vent Connectors Serving a Single Category I Appliance Connector Diameter - D To be used with chimney areas within the size limits at bottom 3" 4" 5" 6" Height Lateral Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max 6 2 NR NR 28 NR NR 52 NR NR 86 NR NR NR NR 25 NR NR 49 NR NR 82 NR NR NR NR 31 NR NR 61 NR NR 103 NR NR NR NR 28 NR NR 57 NR NR 96 NR NR NR NR 25 NR NR 50 NR NR 87 NR NR NR NR 35 NR NR 67 NR NR 114 NR NR NR NR 33 NR NR 62 NR NR 107 NR NR NR NR 28 NR NR 55 NR NR 97 NR NR NR NR NR NR NR 48 NR NR 89 NR NR NR NR 38 NR NR 74 NR NR 124 NR NR NR NR 36 NR NR 68 NR NR 116 NR NR NR NR NR NR NR 60 NR NR 107 NR NR NR NR NR NR NR NR NR NR 97 NR NR NR NR NR NR NR NR NR NR 83 NR NR NR NR 41 NR NR 82 NR NR 137 NR NR NR NR NR NR NR 76 NR NR 128 NR NR NR NR NR NR NR 67 NR NR 115 NR NR NR NR NR NR NR NR NR NR 107 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 50 2 NR NR NR NR NR 92 NR NR 161 NR NR NR NR NR NR NR NR NR NR 151 NR NR NR NR NR NR NR NR NR NR 138 NR NR NR NR NR NR NR NR NR NR 127 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 Minimum Internal Area of Chimney Square Inches Maximum Internal Area of Chimney Square Inches Unitary Products Group 5

6 FIGURE J-4 Table J-4 shall be used when a Single-Wall Vent Connector is attached to a Tile-Lined Masonry Chimney. NOTE: The appliance may be either Category I Draft Hood-equipped or Fan-assisted type. NOTE: "A" is the equivalent cross sectional area of the Tile Liner. Table J-4 Capacity of Masonry Chimney with Single-Wall Vent Connectors Serving a Single Category I Appliance Connector Diameter - D To be used with chimney areas within the size limits at bottom 3" 4" 5" 6" Height Lateral Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max 6 2 NR NR 28 NR NR 52 NR NR 86 NR NR NR NR 25 NR NR 48 NR NR 81 NR NR NR NR 31 NR NR 61 NR NR 102 NR NR NR NR 28 NR NR 56 NR NR 95 NR NR NR NR 24 NR NR 49 NR NR 86 NR NR NR NR 35 NR NR 67 NR NR 113 NR NR NR NR 32 NR NR 61 NR NR 106 NR NR NR NR 27 NR NR 54 NR NR 96 NR NR NR NR NR NR NR 46 NR NR 87 NR NR NR NR 38 NR NR 73 NR NR 123 NR NR NR NR 35 NR NR 67 NR NR 115 NR NR NR NR NR NR NR 59 NR NR 105 NR NR NR NR NR NR NR NR NR NR 95 NR NR NR NR NR NR NR NR NR NR 80 NR NR NR NR 41 NR NR 81 NR NR 136 NR NR NR NR NR NR NR 75 NR NR 127 NR NR NR NR NR NR NR 66 NR NR 113 NR NR NR NR NR NR NR NR NR NR 105 NR NR NR NR NR NR NR NR NR NR 88 NR NR NR NR NR NR NR NR NR NR NR NR NR NR 50 2 NR NR NR NR NR 91 NR NR 160 NR NR NR NR NR NR NR NR NR NR 149 NR NR NR NR NR NR NR NR NR NR 136 NR NR NR NR NR NR NR NR NR NR 124 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 Minimum Internal Area of Chimney Square Inches Maximum Internal Area of Chimney Square Inches Unitary Products Group

7 Table J-5 Capacity of Single-Wall Metal Pipe or Type B Asbestos Cement Vents Serving a Single Draft Hood-Equipped Appliance Height H (ft) Lateral L (ft) Vent and Connector Diameter - D 3" 4" 5" 6" 7" Maximum Appliance Input Rating in Thousands of Btu Per Hour 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 NR NR NR 222 Unitary Products Group 7

8 MULTI-APPLIANCE Notes for Multiple Appliance Vents (See Tables J-6 to J-10). Connector Diameter Maximum Connector Horizontal Length (Inches) (mm) (Feet) (m) 3 (76.2) 4-1/2 (1.37) 4 (102) 6 (1.83) 5 (127) 7-1/2 (2.29) 6 (152) 9 (2.74) 7 (178) 10-1/2 (3.20) 8 (203) 12 (3.65) 9 (229) 13-1/2 (4.11) 10 (254) 15 (4.57) 12 (305) 18 (5.49) 14 (356) 21 (6.40) 16 (406) 24 (7.32) 18 (457) 27 (8.22) 20 (508) 30 (9.14) 22 (559) 33 (10.06) 24 (610) 36 (10.97) 1. The maximum vent connector horizontal length inch of vent-connector diameter as follows: 2. The vent connector shall be routed to the vent utilizing the shortest possible route. Longer connector than those listed above are permitted under the following conditions. (a) The maximum capacity of the vent connector shall not be reduced more than 10 percent for each additional multiple of the length listed above. For example, the maximum length listed above for a 4-inch (120 mm) connector is 6 feet (1.83 m). With a connector length greater than 12 feet (3.66 m) but not exceeding 18 feet (5.49 m), the maximum capacity must be reduced by 20 percent (0.80 x maximum vent capacity); (b) The minimum capacity shall be determined by referring to the corresponding single appliance table (Tables J-1 to J-2). In this case, for each connector and common vent from the appliance to the vent termination shall be treated as a single appliance vent, as if the other appliances were not present. 3. If vent connectors are combined prior to entering the common vent, the maximum common vent capacity listed in the common venting tables shall be reduced by 10 percent (0.90 x maximum vent capacity). (See Figure J-9). The length of the common vent connector manifold (L o) shall not exceed 1-1/2 feet (18 inches) (457 mm) for each inch (25.4 mm) of common vent connector-manifold diameter (D). 4. If the common vertical vent is offset as shown in Figure J-10, the maximum common vent capacity listed in the common venting tables shall be reduced by 20 percent (0.80 x maximum vent capacity), the equivalent of two 90-degree (1.57 rad) elbows. The horizontal length of the common vent offset shall not exceed 1-1/2 feet (457 mm) for each inch (25.4 mm) of common-vent diameter. 5. Excluding elbows counted in (4) above, for each additional elbow in excess of two, the maximum capacity of that portion of the venting system shall be reduced by 10 percent. NOTE: Two 45-degree (0.79) rad) elbows are equivalent to one 90-degree (1.57 rad elbow). 6. The common vent diameter shall be at least as large as the largest vent-connector diameter. 7. Interconnection fittings must be the same size as the common vent. 8. Sea-level input ratings shall be used when determining maximum capacity for high-altitude installation. Actual input (derated for altitude) shall be used to determine minimum capacity for high-altitude installation. 9. For multiple units of gas utilization equipment all located on one floor, available total height ("H") shall be measured from the highest draft hood outlet or flue collar up to the level of the cap or terminal. Connector rise ("R") shall be measured from the draft hood outlet or flue collar to the level where the vent gas streams come together. (Not applicable to multistory). 10. For multistory installations, available total height for each segment of the system ("H") shall be the vertical distance between the highest draft hood outlet or flue collar entering that segment and the center line of the next higher interconnection tee. (See Figure J-11). 11. The size of the lowest connector and of the vertical vent leading to the lowest interconnection of the multistory system shall be in accordance with Table J-1 or J-2 for available total height ("H") up to the lowest interconnection. (See Figure J-11). 12. Vertical common vents shall have no offsets when used in multistory systems. 13. When two or more appliances are connected to a vertical vent or chimney, the flow area of the largest section of vertical vent shall not exceed seven times the flow area of the smallest flue collar area or draft hood outlet area unless designed in accordance with approved engineering methods. 14. For appliances with more than one input rate, the minimum vent capacity determined from the tables shall be less than the lowest appliance input rating and the maximum vent capacity determined from the tables should be greater than the highest appliance input rating. 15. Listed corrugated metallic chimney-liner systems in masonry chimneys should be sized by using Table J-6 or J-7 for Type B vents with the maximum capacity reduced by 20 percent (0.80 x maximum table capacity) and the minimum capacity as shown in Tables J-6 or J-7. corrugated metal venting systems installed with bends or offsets require additional reduction of the vent maximum capacity. (See Note 5). 16. The tables included in this Part shall be used for chimneys and vents not exposed to the outdoors below the roof line. Exterior chimneys or vents exposed to the outdoors below the roof line may experience continuous condensation depending on locality. Consult local serving gas suppliers, or the authority having jurisdiction. A Type B vent or listed chimney-lining system passing through an otherwise unused masonry chimney flue shall be considered to be an interior-vent system. 17. Vent connectors shall not be sized upward more than two sizes greater than the appliance categorized vent diameter, flue collar diameter, or draft hood-outlet diameter. 18. All combinations of pipe sizes, single-wall, and doublewall metal pipe shall be 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, as if they were used for the entire length of the subject connector or vent. If a single-wall and Type B double-wall metal pipe are used for vent connectors, the common vent must be sized using Table J-7 or J-9 as appropriate. 8 Unitary Products Group

9 19. The draft hood inlet or flue collar of the smallest input appliance shall be located closest to, or under, the common vent. 20. When a table permits more than one diameter of of pipe to be used for a connector or vent, all the permitted sizes shall be permitted to be used. NOTE: In general, it is preferable to use the smallest diameter permitted to minimize heat loss. 21. Interpolation shall be permitted in calculating capacities for vent dimensions which fall between table entries. 22. Extrapolation beyond the table entries shall not be permitted. FIGURE J-5 Table J-6 shall be used when Type B Double-Wall Vent Pipe Connectors are attached to a Type B Double-Wall Common Vent NOTE: Each appliance may be either Category I Draft Hood-equipped or Fan-assisted type. Table J-6 Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors Servicing Two or More Category I Appliances VENT CONNECTOR CAPACITY Vent and Connector Diameter - D Vent Connector 3" 4" 5" 6" 7" Height Rise Appliance Input Rating in Thousands of Btu Per Hour H R FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max COMMON VENT CAPACITY Vent Height H (ft) Common Vent diameter - D 4" 5" 6" 7" 8" 9" 10" Combined Appliance Input Rating in Thousands of Btu Per Hour FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT Unitary Products Group 9

10 FIGURE J-6 Table J-7 shall be used when Single Wall Vent Connectors are attached to a Type B Double-Wall Common Vent NOTE: Each appliance may be either Category I Draft Hood-equipped or Fan-assisted type. Table J-7 Capacity of Type B Double-Wall Vents with Single-Wall Connectors Servicing Two or More Category I Appliances VENT CONNECTOR CAPACITY Vent and Connector Diameter - D Vent Connector 3" 4" 5" 6" 7" Height Rise Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 6 1 NR NR 26 NR NR 46 NR NR 71 NR NR NR NR 38 NR NR 55 NR NR NR NR 34 NR NR NR NR NR NR NR NR COMMON VENT CAPACITY Vent Height H (ft) Common Vent diameter - D 4" 5" 6" 7" 8" 9" 10" Combined Appliance Input Rating in Thousands of Btu Per Hour FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT Unitary Products Group

11 FIGURE J-7 Table J-8 shall be used when Type B Double Wall Vent Connectors are attached to a Tile-Lined Masonry Chimney. NOTE: Each appliance may be either Category I Draft Hood-equipped or Fan-assisted type. NOTE: "A" is the equilvalent cross sectional area of the Tile Liner. Table J-8 Capacity of Masonry Chimney with Type B Double-Wall Connectors Servicing Two or More Category I Appliances VENT CONNECTOR CAPACITY Vent and Connector Diameter - D Vent Connector 3" 4" 5" 6" 7" Height Rise Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 6 1 NR NR COMMON VENT CAPACITY Vent Height H (ft) Minimum Internal Area of Chimney, Square Inches Combined Appliance Input Rating in Thousands of Btu Per Hour FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT 6 NR NR NR NR NR NR NR NR 853 NR 8 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 NR NR NR 91 NR NR 165 NR NR NR NR NR NR NR NR 85 NR NR 163 NR NR 284 NR NR 435 NR NR NR NR NR Unitary Products Group 11

12 FIGURE J-8 Table J-9 shall be used when Single Wall Vent Connectors are connected to a Tile-Lined Masonry Chimney. NOTE: Each appliance may be either Category I Draft Hood-equipped or Fan-assisted type. NOTE: "A" is the equilvalent cross sectional area of the Tile Liner. Table J-9 Capacity of Masonry Chimney with Single-Wall Connectors Servicing Two or More Category I Appliances VENT CONNECTOR CAPACITY Vent and Connector Diameter - D Vent Connector 3" 4" 5" 6" 7" Height Rise Appliance Input Rating in Thousands of Btu Per Hour H L FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT (ft) (ft) Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max 6 1 NR NR 21 NR NR 39 NR NR NR NR 28 NR NR 52 NR NR NR NR 34 NR NR NR NR 23 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR COMMON VENT CAPACITY Vent Height H (ft) Minimum Internal Area of Chimney, Square Inches Combined Appliance Input Rating in Thousands of Btu Per Hour FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN FAN NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT FAN NAT NAT 6 NR NR NR NR NR NR NR NR 846 NR 8 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 NR NR NR 90 NR NR 162 NR NR NR NR NR NR NR NR 83 NR NR 160 NR NR 280 NR NR 429 NR NR NR NR NR Unitary Products Group

13 Table J-10 Capacity of a Single-Wall Metal Pipe or Type B Asbestos Cement Vent Serving Two or More Draft Hood-Equipped Appliances VENT CONNECTOR CAPACITY Total Vent Height "H" 6-8" and up Connector Rise "R" Vent Connector Diameter - D 3" 4" 5" 6" 7" Maximum Appliance Input Rating in Thousands of Btu Per Hour COMMON VENT CAPACITY Total Vent Height "H" 6-8" and up Connector Rise "R" Vent Connector Diameter - D 3" 4" 5" 6" 7" 8" Maximum Appliance Input Rating in Thousands of Btu Per Hour Table J-11 Masonry Chimney Liner Dimensions with Circular Equivalents Nominal Liner Size Inches Inside Dimensions of Linear Inches 4 x 8 2-1/2 x x6-1/2 8 x 8 6-3/4 x x6-3/4 Inside Diameter or Equivalent Diameter Inches x /4 x 9-3/ x /2 x x13-1/ x /4 x 13-1/ Equivalent Area Inches x x When liner sizes differ dimensionally from those in Table J-7, equivalent diameters may be determined from published tables for square and rectangular ducts of equivalent carrying capacity or by other engineering methods. Unitary Products Group 13

14 FIGURE J-9 EXAMPLE A: Manifolded Common Vent Connector L o shall be no greater than eighteen times the common vent connector manifold inside diameter; i.e. a 4-inch inside diameter common vent connector manifold shall not exceed 72 inches in length. (See Note 3) NOTE: This is an illustration of a typical manifolded vent connector. Different appliance, vent connector, or common-vent types are possible. Consult the notes for Common Venting. FIGURE J-10 EXAMPLE B: Offset Common Vent NOTE: This is an illustration of a typical Offset Vent. Different appliance and vent connector types are possible. Consult the notes for Single Appliance and Common Venting. 14 Unitary Products Group

15 FIGURE J-11 Multi-Story Gas vent Design Procedure for Each Segment of System (See Notes 9, 10, 11, 12 & 13) Multi-Story Gas Vent Design Procedure for each Segment of System Common Vent Size Depends on: Combined Inputs Available Total Height "H" Table J-6 Common Vent Vertical Common Vent with no Offsets Vent Connector Size Depends on: Input Rise Available Total Heigt "H" Table J-6 Connectors FIGURE J-12 Multi-Story Vent System (See Notes 9, 10, 11, 12 & 13) Principles of Design of Multistory Vents Using Vent Connector and Common Vent Design Tables Unitary Products Group 15

16 Subject to change without notice. Printed in U.S.A. Copyright by Unitary Products Group All rights reserved AD3V Unitary Products Group Post Office Box 1592 York Pennsylvania