510.1 Single Appliance Vent Table 510.1.2(1) through

Table 510.1.2(6). Table 510.1.2(1) through Table 510.1.2(6) shall not be used where obstructions are installed in the venting system. The installation of vents serving listed appliances with vent dampers shall be in accordance with the appliance manufacturer’s installation instructions or in accordance with the following: (1) The maximum capacity of the vent system shall be deter mined using the NAT Max column.

(1) The maximum capacity of the vent system shall be deter mined using the NAT Max column. (2) The minimum capacity shall be determined as though the

appliance were a fan-assisted appliance, using the FAN

The minimum capacity shall be determined as though the

appliance were a fan-assisted appliance, using the FAN Min column to determine the minimum capacity of the vent system. Where the corresponding “FAN Min” is “NA”, the vent configuration shall not be permitted, and an alternative venting configuration shall be utilized.

[NFPA 54:13.1.1] 510.1.1 Vent Downsizing. Where the vent size determined from the tables is smaller than the appliance draft hood outlet or flue collar, the use of the smaller size shall be permitted provided that the installation is in accordance with the following requirements: (1) The total vent height (H) is not less than 10 feet

(3048 mm).

(1) The total vent height (H) is not less than 10 feet

(3048 mm). (2) Vents for appliance draft hood outlets or flue collars

12 inches (300 mm) in diameter or smaller are not

(2) Vents for appliance draft hood outlets or flue collars

12 inches (300 mm) in diameter or smaller are not reduced more than one table size. (3) Vents for appliance draft hood outlets or flue collars

exceeding 12 inches (300 mm) in diameter are not

(3) Vents for appliance draft hood outlets or flue collars

exceeding 12 inches (300 mm) in diameter are not reduced more than two table sizes. (4) The maximum capacity listed in the tables for a fan assisted appliance is reduced by 10 percent (0.90 x

(4) The maximum capacity listed in the tables for a fan assisted appliance is reduced by 10 percent (0.90 x maximum table capacity). (5) The draft hood outlet exceeds 4 inches (100 mm) in

diameter. A 3 inch (80 mm) diameter vent shall not

(1) Draft regulators and safety controls specifically listed for

installation in venting systems and installed in accordance with the manufacturer’s installation instructions. (2) Approved draft regulators and safety controls designed

and installed in accordance with approved engineering

(2) Approved draft regulators and safety controls designed

and installed in accordance with approved engineering methods. (3) Listed heat reclaimers and automatically operated vent

dampers installed in accordance with the manufacturer’s

(3) Listed heat reclaimers and automatically operated vent

dampers installed in accordance with the manufacturer’s installation instructions. (4) Vent dampers serving listed appliances installed in accor dance with Section 510.1 or Section 510.2 or other

(4) Vent dampers serving listed appliances installed in accor dance with Section 510.1 or Section 510.2 or other approved engineering methods. (5) Approved economizers, heat reclaimers, and recupera tors installed in venting systems of appliances not

Approved economizers, heat reclaimers, and recupera tors installed in venting systems of appliances not required to be equipped with draft hoods provided the appliance manufacturer’s installation instructions cover

(5) The draft hood outlet exceeds 4 inches (100 mm) in

diameter. A 3 inch (80 mm) diameter vent shall not be connected to a 4 inch (100 mm) diameter draft hood outlet. This provision shall not apply to fanassisted appliances. [NFPA 54:13.1.2] 510.1.2 Elbows. Single-appliance venting configurations with zero lateral lengths in Table 510.1.2(1), Table 510.1.2(2), and Table 510.1.2(5) shall not have elbows in the venting system. Single-appliance venting with lateral lengths includes two 90 degree (1.57 rad) elbows. For each additional elbow up to and including 45 degrees (0.79 rad), the maximum capacity listed in the venting tables shall be reduced by 5 percent. For each additional elbow greater than 45 degrees (0.79 rad) up to and including 90 degrees (1.57 rad), the maximum capacity listed in the venting tables shall be reduced by 10 percent. Where multiple offsets occur in a vent, the total lateral length of offsets combined shall not exceed that specified in Table 510.1.2(1) through Table 510.1.2(5).

[NFPA 54:13.1.3]

102 2019 CALIFORNIA PLUMBING CODE

WATER HEATERS

510.1.3 Zero Lateral. Zero lateral (L) shall apply to a straight vertical vent attached to a top outlet draft hood or flue collar. [NFPA 54:13.1.4] 510.1.4 High-Altitude Installations. Sea level input ratings shall be used where determining maximum capacity for high-altitude installation. Actual input (derated for altitude) shall be used for determining minimum capacity for high-altitude installation. [NFPA 54:13.1.5] 510.1.5 Multiple Input Ratings. For appliances with more than one input rate, the minimum vent capacity (FAN Min) determined from the tables shall be less than the lowest appliance input rating, and the maximum vent capacity (FAN Max/NAT Max) determined from the tables shall exceed the highest appliance rating input.

[NFPA 54:13.1.6] 510.1.6 Corrugated Chimney Liner Reduction. Listed corrugated metallic chimney liner systems in masonry chimneys shall be sized by using Table 510.1.2(1) or Table 510.1.2(2) for Type B vents with the maximum capacity reduced by 20 percent (0.80 x maximum capacity) and the minimum capacity as shown in Table 510.1.2(1) or Table 510.1.2(2).

Corrugated metallic liner systems installed with bends or offsets shall have their maximum capacity further reduced in accordance with Section 510.1.2. The 20 percent reduction for corrugated metallic chimney liner systems includes an allowance for one long radius 90 degree (1.57 rad) turn at the bottom of the liner. [NFPA 54:13.1.7] 510.1.7 Connection to Chimney Liners. Connections between chimney liners and listed double-wall connectors shall be made with listed adapters designed for such purposes. [NFPA 54:13.1.8] 510.1.8 Vertical Vent Upsizing Using 7 x Rule. Where the vertical vent has a larger diameter than the vent connector, the vertical vent diameter shall be used to determine the minimum vent capacity, and the connector diameter shall be used to determine the maximum vent capacity. The flow area 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 designed in accordance with approved engineering methods. [NFPA 54:13.1.9] 510.1.9 Draft Hood Conversion Accessories. Draft hood conversion accessories for use with masonry chimneys venting listed Category I fan-assisted appliances shall be listed and installed in accordance with the listed accessory manufacturer’s installation instructions.

[NFPA 54:13.1.10] 510.1.10 Chimney and Vent Locations. Table 510.1.2(1) through Table 510.1.2(5) shall be used only for chimneys and vents not exposed to the outdoors below the roof line. A Type B vent or listed chimney lining system passing through an unused masonry chimney flue shall not be considered to be exposed to the outdoors. Where vents extend outdoors above the roof more than 5 feet (1524 mm) higher than required by Table

(2) The lower appliance input rating shown in the table

entries for FAN Max and NAT Max column values; and the higher appliance input rating for the FAN Min column values. [NFPA 54:13.1.18]