511.1 Exhaust Fans for Commercial Cooking Operations

Exhaust fans shall be installed in accordance with Section 511.1.1 through Section 511.1.6. Exhaust fans shall comply with UL 762 and be installed in accordance with the manufacturer's installation instructions.

Upblast fans with motors surrounded by the airstream shall be hinged and supplied with flexible weatherproof electrical cable, and service hold-open retainers. Installation shall comply with the requirements of Section 510.9. Upblast fans shall have a drain directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L). [NFPA 96:8.1.2]

In-line fans shall be of the type with the motor located outside the airstream and with belts and pulleys protected from the airstream by a greasetight housing. In-line fans shall be connected to the exhaust duct by flanges securely bolted as shown in Figure 511.1.2(1) through Figure 511.1.2(4), or by a system specifically listed for such use. Flexible connectors shall not be used. [NFPA 96:8.1.3.1 — 8.1.3.3]

For SI units: 1 inch = 25.4 mm, °C = (°F—32)/1.8)

FIGURE 511.1.2(1)
TYPICAL SECTION OF DUCT-TO-FAN CONNECTION-BUTT JOINT METHOD
[NFPA 96: FIGURE 8.1.3.2(a)]

 

For SI units: 1 inch = 25.4 mm, °C = (°F—32)/1.8)

FIGURE 511.1.2(2)
TYPICAL SECTION OF DUCT-TO-FAN CONNECTION-OVERLAPPING METHOD
[NFPA 96: FIGURE 8.1.3.2(b)]

 

For SI units: 1 inch = 25.4 mm, °C = (°F—32)/1.8

FIGURE 511.1.2(3)
TYPICAL SECTION OF DUCT-TO-FAN CONNECTION-SEALANT METHOD
[NFPA 96: FIGURE 8.1.3.2(c)]

 

For SI units: 1 inch = 25.4 mm, °C = (°F—32)/1.8

 

FIGURE 511.1.2(4)
TYPICAL SECTION OF DUCT-TO-FAN CONNECTION-DIRECT TO FAN INLET CONE METHOD
[NFPA 96: FIGURE 8.1.3.2(d)]

Where the design or positioning of the fan allows grease to be trapped, a drain directed to a readily accessible and visible grease receptacle, not exceeding 1 gallon (4 L), shall be provided. In-line exhaust fans shall be located in an easily accessible area of approved size to allow for service or removal. Where the duct system connected to the fan is in an enclosure, the space or room in which the exhaust fan is located shall have the same fire resistance rating as the enclosure. [NFPA 96:8.1.3.4 — 8.1.3.6]

Utility set exhaust fans shall be installed in accordance with Section 511.1.3.1 through Section 511.1.3.3.

Fans installed at the rooftop termination point shall be in accordance with the following:

1. Section 510.9.1 and Section 510.9.1.2.
2. Flexible connectors shall be permitted.
3. A drain shall be directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L).

Fans installed within the building shall be in accordance with the following:

1. Located in an accessible area of a size to allow for service or removal. [NFPA 96:8.1.4.2]
2. Flexible connectors shall be prohibited. [NFPA 96:8.1.4.5]
3. A drain shall be directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L). [NFPA 96:8.1.4.6]

Duct systems connected to fans in an enclosure shall be in accordance with the following:

1. The space or room in which the exhaust fan is located shall have the same fire resistance rating as the enclosure.
2. The fan shall be connected to the exhaust duct by flanges securely bolted as shown in Figure 511.1.2(1) through Figure 511.1.2(4) or by a system specifically listed for such use. [NFPA 96:8.1.4.3, 8.1.4.4]

Exhaust fan housings shall be constructed of carbon steel not less than 0.060 of an inch (1.524 mm) (No. 16 MSG) in thickness, of stainless steel not less than 0.048 of an inch (1.219 mm) (No. 18 MSG) in thickness, or, where listed, in accordance with the terms of the listing. [NFPA 96:8.1.5]

Openings for cleaning, servicing, and inspection shall be in accordance with the requirements of Section 510.3.2. Clearances shall be in accordance with the requirements of Section 507.4, or Section 510.7.3 and Section 510.7.4 where installed within an enclosure. [NFPA 96:8.1.6.1, 8.1.6.2]

Wiring and electrical equipment shall comply with NFPA 70. [NFPA 96:8.1.7]