Commercial food service hoods shall exhaust a minimum net quantity of air determined in accordance with this section and Sections 507.5.1 through 507.5.5. The net quantity of exhaust air shall be calculated by subtracting any airflow supplied directly to a hood cavity from the total exhaust flow rate of a hood. Where any combination of heavy-duty, medium-duty and light-duty cooking appliances are utilized under a single hood, the exhaust rate required by this section for the heaviest duty appliance covered by the hood shall be used for the entire hood.
The minimum net airflow for hoods, as determined by Section 507.1, used for extra-heavy-duty cooking appliances shall be determined as follows:
| Type of Hood | CFM per linear foot of hood |
| Backshelf/pass-over | Not allowed |
| Double island canopy (per side) | 550 |
| Eyebrow | Not allowed |
| Single island canopy | 700 |
| Wall-mounted canopy | 550 |
For SI: 1 cfm per linear foot = 1.55 L/s per linear meter.
The minimum net airflow for hoods, as determined by Section 507.1, used for heavy-duty cooking appliances shall be determined as follows:
| Type of Hood | CFM per linear foot of hood |
| Backshelf/pass-over | 400 |
| Double island canopy (per side) | 400 |
| Eyebrow | Not allowed |
| Single island canopy | 600 |
| Wall-mounted canopy | 400 |
For SI: 1 cfm per linear foot = 1.55 L/s per linear meter.
The minimum net airflow for hoods, as determined by Section 507.1, used for medium-duty cooking appliances shall be determined as follows:
| Type of Hood | CFM per linear foot of hood |
| Backshelf/pass-over | 300 |
| Double island canopy (per side) | 300 |
| Eyebrow | 250 |
| Single island canopy | 500 |
| Wall-mounted canopy | 300 |
For SI: 1 cfm per linear foot = 1.55 L/s per linear meter.
The minimum net airflow for hoods, as determined by Section 507.1, used for light-duty cooking appliances and food service preparation shall be determined as follows:
| Type of Hood | CFM per linear foot of hood |
| Backshelf/pass-over | 250 |
| Double island canopy (per side) | 250 |
| Eyebrow | 250 |
| Single island canopy | 400 |
| Wall-mounted canopy | 200 |
For SI: 1 cfm per linear foot = 1.55 L/s per linear meter.
The minimum net airflow for Type II hoods used for dishwashing appliances shall be 100 cfm per linear foot (155 L/s per linear meter) of hood length.
Exception: Dishwashing appliances and equipment installed in accordance with Section 507.3.
Exception: Dishwashing appliances and equipment installed in accordance with Section 507.3.