7. System Design for Kitchens
Air Conditioning
Ventilation
Fire Safety
Building Pressurization
Air Distribution
Food Service Equipments
8. Basic Purpose of Kitchen Ventilation
To provide a comfortable environment in the
kitchen
To ensure the safety of the people working in the
kitchen and building occupants by:
Effective removal of Effluents which may include
gaseous, liquid and solid contaminants produced
by the cooking process and products of fuel &
food combustion.
11. Electrostatic Precipitators (ESPs)
Used in the exhaust stream downstream of the
hood and the most common higher efficiency
(HE) device.
By high voltage ionization, particles are collected
on that electrostatic plates.
Efficiency may drop as the ionizer section
becomes dirty and effective surface area is
reduced.
Under heavy loading condition, unit may shut
down because of voltage drop.
12. Grease Emissions
Amount of grease in vapour phase
varies from 30% to 90% by mass.
This is an important factor in
designing the grease removal
system.
Co, CO2, and NOX emissions are
present in gas and not electrical
appliances.
13. Grease Extraction
Without proper filtration, grease will:
Collect in exhaust plenum and duct creating fire
hazard and incur cleaning costs.
Collect at the fan, causing unbalance and
premature failure.
Create undesired odour.
Collect on rooftop equipment and cooling coils.
Pollute the environment.
16. An Exhaust Hood
The Centre Piece of any kitchen Ventilation Systems (KVS).
Not just a sheet metal box but a critical components of a
well engineered system.
Much greater awareness today about the need for an
effective KVS.
Issues are health, safety, efficiency and energy savings.
18. Exhaust Hoods
Type I – for removing grease &
smoke: used for cooking appliances.
Type II – for steam, Vapour, heat &
odour when grease is not present:
used for dishwashers, steam tables,
etc.
20. Type II Hood - OVEN Hoods
Removal of heat & Odour.
Canopy hood with no filters.
Hood size determined with oven door open.
21. Type II Hood – condensate Hood
Removal of heat & Odour & moisture.
Condensate baffle and gutter to condense moist air & drain
the water.
Used over dishwashers.
22. Basic styles of Type I Hoods
Wall Mounted Canopy
Single island
Double island
Back shelf or proximity
Pass Over
Eyebrow
27. Wall Canopy Hood
Cooking appliance placed against
a wall
Minimum air flow requirement
3” built in gap between hood &
wall.
Three finished sides.
Less susceptible to cross drafts.
Minimum Overhang requirement:
6” on sides and 6”-12” in front for
full capture.
28. Single Island Hood
Cooking appliance/s (row)
placed in the middle (not
against a wall).
Four finished sides
More susceptible to cross
drafts.
Recommended overhang:
12” on all 4 sides.
Baffle filters in ‘V’
configuration.
29. Double island Hood
Double row of appliances
placed back to back.
Two wall canopy hoods
placed back to back.
Recommended overhang:
6” – 12” on all 4 sides.
30.
31.
32. Hood Overhang
Minimum Hood Overhang Requirements
(mm)
Hood Type End Front Rear
Wall Mounted Canopy 150 150 -
Single Island 150 150 150
Double Island (Per side) 150 150 -
Eyebrow - 150 -
Back Shelf 150 250* -
Pass Over 150 250* -
* Maximum Setback
33. Minimum Exhaust Flow Rates by Equipments Category
CFM per Linear Meter of Hood
Equipments Duty => Light Medium Heavy Extra
Heavy
Wall Mounted Canopy 660 990 1315 1800
Single Island 1315 1645 1975 2300
Double Island (Per side) 830 990 1315 1800
Eyebrow 830 830 - -
Back Shelf 990 990 1315 -
Pass Over 990 990 1315 -
For a combination of appliances in a row under a single hood, the
flow rate is based on the heaviest duty appliance unless the hood
design permits different rates over different sections of the hood.
34. Hood Overhang
(A) NORMAL VIEW (B) SCHLIEREN VIEW OF
SPILLAGE WITH 4ft DEEP
HOOD WITH 6in OF FRONT
OVERHANG
(C) SCHLIEREN VIEW
DURING CAPTURE &
CONTAINMENT WITH 18 in
OF FRONT OVERHANG
36. Hood Pressure Drop
Pressure Drop across a Hood with
Baffle Filters A General Guide
Exhaust Flow Rate per Linear Meter Ps
(CFM) (MM)
530 – 850 6 -12
850 – 1150 12 – 19
1150 – 1500 19 – 26
> 1500 > 26
40. Fans for Kitchen Exhaust
Kitchen exhaust consists of hot, grease laden air
with some solid particulate matter also.
Fan must be Capable of this air.
Motor must be kept outside the air-stream.
