Lesson 23 Appendix C Exhaust Calculation

Maria’s Restaurant Maria’s

Maria’s Restaurant Design (Staff: Maria & 6 Employees each shift. Glass Store Front and front door) C1 R1 F1 Woman’s Restroom 1 handicap 1 standard Men’s Restroom 1 handicap 1 urinal S3 Shelv.. R3 DW Bar 12 X 10 Seating 12 Counter C6 Bar S2 B2 Ice R4 Shelving/Storage 25 ft. Shelv. B1 C7 C2 Fry S1 Restaurant 33 X 15, 11 X 4 & 11 X 6 Seating 58 CT/O C3 SP SK H1 R2 F2 WH S1 66 ft. Kitchen Area = 533 Sqft Bar Area = 180 Sqft Woman Rest Room = 110 Sqft Men Rest Room = 99 Sqft Bar Area = 180 Sqft Entry Area = 120 Sqft Dinning Area = 605 Sqft

Kitchen Exhaust Requirements Typical Type 1 Exhaust Hood With Perforated Perimeter Supply (11.5 ft. linear length 3,450 CFM hood with 1,150 CFM untempered ASHRAE 62 Class 1 makeup air)

Hood Types Double Island Canopy Eyebrow

Hood Types Wall Mounted Canopy Pass Over

Hood Types Single Island Canopy Back Shelf

Hood Duty Definitions Light Duty: Gas & Electric Ovens, steamers, and ranges. Food Warmers, pasta cookers, pizza ovens, Non- cooking appliance, smoker, rotisserie. Medium Duty: Combi-Ovens, Gas & Electric Fryers, Griddles, Tilting skillets, tilting braising pans grill, hibachi grill, salamander

Hood Duty Definitions Heavy Duty: Upright broiler, electric Char-broiler Extra-Heavy Duty: Gas Char-broiler, Mesquite, infrared broiler, lava rock char-broiler, wok, chain broiler.

Hood Type Definitions Type I hoods: Required over cooking equipment that produces grease laden effluent. Must have a sealed or welded exhaust duct system. Type II hoods: Used over cooking equipment that does not produce grease.

2015 Uniform Mechanical Code (IMC) Airflow Requirement (air class 2) Type 1 Exhaust Hood CFM 2015 Uniform Mechanical Code (IMC) Airflow Requirement (air class 2) Type of Hood Airflow by Duty (CFM per linear foot of hood) Light Medium Heavy Backshelf/Passover 250 300 400 Double Island Canopy Eyebrow Not Allowed Single Island Canopy 500 600 Wall Mounted Canopy 200 11.5 ft hood X 300 CFM = 3,450 CFM

Type 2 Exhaust Hood CFM Type 2 used for dishwasher/humidity removal: Not Less Than 200 CFM per linear foot of hood. 3 ft hood X 200 CFM = 600 CFM

Operational Outside Air Minimums Outside air required for the kitchen side of the building by ASHRAE 62.1 is 119 CFM: Thus, 119 CFM must be brought in at all times. 4,050 CFM will be exhausted through the two kitchen exhaust hoods. That will leave a negative 3,931 CFM of air if only 119 CFM is brought in from the outside. Thus, an additional 3,931 CFM of air will need to be brought into the kitchen if it is to remain at a neutral pressure with respect to the outside. (slightly positive to the outside is preferable)

Kitchen Exhaust Total Cooking Hood: 3,450 CFM Dish washer Hood: 600 CFM Total: 4,050 CFM

Kitchen Exhaust & OA Sketch AIR In 1,150 CFM AIR In 600 CFM AIR In Setting 1: 1,900 CFM Setting 2: 100 CFM EX. AIR #2 Package Heat Pump ERV EX AIR OUT 500 CFM EX. AIR AIR In 500 CFM EX 2 Supply Air 3,200 CFM Return Air Setting 1: 1,300 CFM Setting 2: 3,100 CFM 2 Bathrooms Airflow ½ each EX 1 EX 2 AIR 600 CFM EX AIR Speed/Setting 1: 3,450 CFM Speed/Setting 2: 1,650 CFM Kitchen Area (+0.001” IWC) Bar & Dining Area (+0.004” IWC)

Kitchen Exhaust Total The Total CFM Requiring heating and cooling is Lowered to: 4,050 – 2,050 = 2,000 Cooking Hood: 3,450 CFM Dish washer Hood: 600 CFM Total: 4,050 CFM Bring 1,150 CFM into the hood by a separate outside air fan. Bring 600 CFM to dish wash area when exhaust hood is on through designated outside air fan. Bring 500 CFM into kitchen area from Bathroom ERV constant volume.

Kitchen Exhaust & OA Sketch AIR In 1,150 CFM AIR In 600 CFM AIR In Setting 1: 1,900 CFM Setting 2: 100 CFM EX. AIR #2 Package Heat Pump ERV EX AIR OUT 500 CFM EX. AIR AIR In 500 CFM EX 2 Supply Air 3,200 CFM Return Air Setting 1: 1,300 CFM Setting 2: 3,100 CFM 2 Bathrooms Airflow ½ each EX 1 EX 2 AIR 600 CFM EX AIR Speed/Setting 1: 3,450 CFM Speed/Setting 2: 1,650 CFM Kitchen Area (+0.001” IWC) Bar & Dining Area (+0.004” IWC)

Kitchen Exhaust Requirements Typical Type 1 Exhaust Hood With Perforated Perimeter Supply (11.5 ft. linear length 3,450 CFM hood with 1,150 CFM untempered ASHRAE 62 Class 1 makeup air)

Further Savings: Two Speed Type I Exhaust Hood The Type I hood selected is designed with an automated control that senses usage. When there is no usage, down and the hood fan lowers it’s speed so only 1,650 CFM are being exhausted by the hood when the cooking equipment is not being used. Thus, only 100 CFM is being conditioned by the Kitchen HVAC system.

Kitchen Exhaust & OA Sketch AIR In 1,150 CFM AIR In 600 CFM AIR In Setting 1: 1,900 CFM Setting 2: 100 CFM EX. AIR #2 Package Heat Pump ERV EX AIR OUT 500 CFM EX. AIR AIR In 500 CFM EX 2 Supply Air 3,200 CFM Return Air Setting 1: 1,300 CFM Setting 2: 3,100 CFM 2 Bathrooms Airflow ½ each EX 1 EX 2 AIR 600 CFM EX AIR Speed/Setting 1: 3,450 CFM Speed/Setting 2: 1,650 CFM Kitchen Area (+0.001” IWC) Bar & Dining Area (+0.004” IWC)

Dining & Bar Exhaust & OA Sketch AIR In 500 CFM AIR In 689 CFM # 1 Package Heat Pump ERV EX AIR OUT 500 CFM EX. AIR Supply Air 2,400 CFM 2 Bathrooms Airflow ½ each Return Air 1,711 CFM Kitchen Area (+0.001” IWC) Bar & Dining Area (+0.004” IWC)

Dedicated Outdoor Air Unit

Field Notes Technicians should be able to identify imbalances in exhaust and makeup air by simply verifying airflow directions. Technicians can use a piece of tissue or a smoke pencil to identify airflow paths and the relative building pressures they indicate. Most commercial buildings have an airflow related problem somewhere within their walls. Understanding how the systems work together is very important before making an adjustment to any of the components.