Halton - Kitchen Design Guide

Care forWellbeing
Enabling Indoor Air
Halton design guide for indoor air

KDG/1309/UK
climate in commercial kitchens

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Design Fundamentals
Commercial Kitchen Ventilation Systems

The commercial kitchen is a unique space where and thermal comfort. The kitchen supply air, whether
many different HVAC applications take place within a mechanical or transfer or a combination of both,
single environment. Exhaust, supply, transfer, should be of an amount that creates a small negative
refrigeration, building pressurisation and air pressure in the kitchen space. This will avoid odours
conditioning all must be considered in the design of and contaminated air escaping into surrounding areas.
most commercial kitchens. Therefore the correct exhaust air flow quantity is
It is obvious that the main activity in the commercial fundamental to ensure good system operation,
kitchen is the cooking process. This activity generates thermal comfort and improved IAQ.
heat and effluent that must be captured and Similar considerations should be given to washing-up,
exhausted from the space in order to control odour food preparation and serving areas.

Picture 1.

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Initial Design Considerations Heat Gain and Emissions Inside
the Kitchen
The modes of heat gain in a space may include solar
radiation and heat transfer through the construction Cooking can be described as a process that adds heat
together with heat generated by occupants, lights and
to food. As heat is applied to the food, effluent (1) is
appliances and miscellaneous heat gains as air
released into the surrounding environment. This
infiltration should also be considered.
effluent release includes water vapour, organic
Sensible heat (or dry heat) is directly added to the material released from the food itself, and heat that
conditioned space by conduction, convection and was not absorbed by the food being cooked. Often,
radiation. Latent heat gain occurs when moisture is when pre-cooked food is reheated, a reduced amount
added to the space (e.g., from vapour emitted by the of effluent is released, but water vapour is still emitted
cooking process, equipment and occupants). Space into the to the surrounding space.
heat gain by radiation is not immediate. Radiant
The hot cooking surface (or fluid, such as oil) and
energy must first be absorbed by the surfaces that
products create thermal air currents (called a thermal
enclose the space (walls, floor, and ceiling) and by the
plume) that are received or captured by the hood and
objects in the space (furniture, people, etc.). As soon
as these surfaces and objects become warmer than then exhausted. If this thermal plume is not totally
the space air, some of the heat is transferred to the air captured and contained by the hood, they become a
in the space by convection (see picture 2). heat load to the space.
To calculate a space cooling load, detailed building There are numerous secondary sources of heat in the
design information and weather data at selected kitchen (such as lighting, people, and hot meals) that
design conditions are required. Generally, the following
contribute to the cooling load as presented in table 1.
information is required:

• building characteristics Load W

• configuration (e.g, building location) Lighting 21-54/m2
People 130/person
• outdoor design conditions
Hot meal 15/meal
• indoor design conditions Cooking eq. varies
• operating schedules Refrigeration varies
• date and time of day Table 1. Cooling load from various sources

However, in commercial kitchens, cooking processes

contribute the majority of heat gains in the space.

1
2

1 Thermal plumes 2 Radiant heat

Picture 2. Heat gain and emission inside the kitchen

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Thermal Comfort, Productivity and Health Met is a unit used to express the metabolic rate per
unit Dubois area, defined as the metabolic rate of a
Thermal Comfort sedentary person, 1 met = 50 kcal/(hr.m2) = 58.2 W/m2.
One reason for the low popularity of kitchen work is
the unsatisfactory thermal conditions.
Assymmetric Thermal Radiation
Thermal comfort is a state where a person is satisfied
with the thermal conditions. In the kitchen, the asymmetry of radiation between
the cooking appliances and the surrounding walls is
The International Organisation for Standardisation considerable as the temperature difference of radiation
(ISO) specifies such a concept as the predicted is generally much higher than 20° C.
percentage of dissatisfied occupants (PPD) and the
predicted mean vote (PMV) of occupants.
PMV represents a scale from -3 to 3, -from cold to hot -, 80 Warm ceiling
with 0 being neutral. PPD tells what percentage of
occupants are likely to be dissatisfied with the thermal 40 Cool wall

environment. These two concepts take into account four

Percent Dissatisfied
factors affecting thermal comfort: 20

Cool ceiling Warm wall

• air temperature 10
• radiation
5
• air movement
• humidity
2

1
0 5 10 15 20 25 30 35 °C
Radiant Temperature Asymmetry

Figure 2. Assymmetric thermal radiation

Ventilation Effectiveness and Air Distribution

System

The Effect of Air Supply

Ventilation effectiveness can be described as the
ability of ventilation system to achieve design
conditions in the space (air temperature, humidity,
Figure 1. PPD as a function of PMV concentration of impurities and air velocity) at
minimum energy consumption. Air distribution
The percentage of dissatisfied people remains under methods used in the kitchen should provide adequate
10% in neutral conditions if the vertical temperature ventilation in the occupied zone, without disturbing the
difference between the head and the feet is less than thermal plume.
3°C and there are no other non-symmetrical
temperature factors in the space. A temperature In the commercial kitchen environment the supply
difference of 6-8°C increases the dissatisfied airflow rate required to ventilate the space is a major
percentage to 40-70%. factor contributing to the system energy consumption.
There are also important personal parameters Traditionally high velocity mixing or low velocity mixing
influencing the thermal comfort (typical values in systems have been used. Now there is a third alternative
kitchen environment in parenthesis): that clearly demonstrates improved thermal comfort over
mixing systems, this is displacement ventilation.
• clothing (0.5 - 0.8 clo)
• activity (1.6 - 2.0 met) The supply air (make-up air) can be delivered to the
kitchen in two ways:
Clo expresses the unit of the thermal insulation of • high velocity or mixiing ventilation
clothing (1 clo = 0.155 m2 K/W ). • low velocity or displacement.

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Low Velocity or Displacement Ventilation
Here, the cooler-than-surrounding supply air is
distributed with a low velocity to the occupied zone. In
this way, fresh air is supplied to where it is needed.
Because of its low velocity, this supply air does not
disturb the hood function.

Picture 4. High velocity or mixing ventilation

In the case of mixing ventilation, with an

intensity of turbulence from 30 to 50 %, one
finds 20 % of people dissatisfied in the following
conditions:

air temperature. (°C) 20 26

air velocity (m/s) 0.15 0.25
Table 2. Air temperature/air velocity

Refer to section Effect of Air Distribution System page

Picture 3. Low velocity or displacement ventilation 39 for a detailed comparison between mixing and
displacement systems in a typical kitchen
environment.
With a displacement system the intensity of
turbulence of about 10 %, one accepts velocities
between 0.25 and 0.40 m/s, with the air
between 20 and 26°C respectively with 20% of
people dissatisfied.

High velocity or Mixing Ventilation

Everything that is released from the cooking process
is mixed with the supply air. Obviously impurities and
heat are mixed with surrounding air. Also the high
velocity supply air disturbs the hood function.

Picture 5. Recommended design criteria

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Productivity

Labour shortages are the top challenge that 27°C in the kitchen the productivity of the restaurant
commercial restaurants face today. The average age of employees is reduced to 80 % (see picture 6). That
a restaurant worker is between 16 and 24 years. In a translates to losses of about $40,000 yearly on
recent survey conducted by the National Restaurant salaries and wages for an owner of a 100-seat
Association in USA, over 52% of respondents said restaurant.
that finding qualified motivated labour was their main
concern.

Room air temperature affects a person’s capacity to

work. Comfortable thermal conditions decrease the
number of accidents occurring in the work place.
When the indoor temperature is too high (over 28 °C
in commercial kitchens) the productivity and general
comfort diminish rapidly.

The average restaurant spends about $2,000 yearly on

salaries in the USA, wages and benefits per seat. If
the air temperature in the restaurant is maintained at Picture 6. Productivity vs. Room Air Temperature

Health

There are several studies dealing with cooking and The risk was further increased among women stir-
health issues. The survey confirmed that cooking frying meat daily whose kitchens were filled with oily
fumes contain hazardous components in both Western fumes during cooking. Also, the statistical link
and Asian types of kitchens. In one study, the fumes between chronic coughs, phlegm and breathlessness
generated by frying pork and beef were found to be on exertion and cooking were found.
mutagenic. In Asian types of kitchens, a high
concentration of carcinogens in cooking oil fumes has In addition to that, Cinni Little states, that three
been discovered. All this indicates that kitchen quarters of the population of mainland China alone use
workers may be exposed to a relatively high diesel as fuel type instead of town gas or LPG,
concentration of airborne impurities and that cooks are causing extensive bronchial and respiratory problems
potentially exposed to relatively high levels of among kitchen workers, which is possibly exacerbated
mutagens and carcinogens. by an air stream introduced into the burner mix.

Chinese women are recognised to have a high

incidence of lung cancer despite a low smoking rate
e.g. only 3% of women smoke in Singapore. The
studies carried out show that inhalation of carcinogens
generated during frying of meat may increase the risk
of lung cancer.

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Reduction of Health Impact
The range of thermal comfort neutrality acceptable highest acceptable temperature (Weihe 1987, quoted
without any impact on health has been proposed as in WHO 1990). Symptoms of discomfort and health
running between 17°C as the lowest and 31°C as the risks outside this range are indicated in table 3.

<< < 17 °C > 31 °C >>

Table 3. Health effects of thermal microclimates lying outside the neutral comfort zone

Ventilation Rate
The airflow and air distribution methods used in the ventilation air is supplied equally throughout the
kitchen should provide adequate ventilation in the occupied zone. Some common faults are to locate the
occupied zone, without disturbing the thermal plume supply and exhaust units too close to each other,
as it rises into the hood system. The German VDI-2052 causing ‘short-circuiting’ of the air directly from the
standard states that a: supply opening to the exhaust openings. Also, placing
the high velocity supply diffusers too close to the
Ventilation rate over 40 vol./h result on the basis of the hood system reduces the ability of the hood system
heat load, may lead to draughts. to provide sufficient capture and containment (C&C) of
the thermal plume.
The location of supply and exhaust units are also Recent studies show that the type of air distribution
important for providing good ventilation. Ventilating system utilised affects the amount of exhaust needed
systems should be designed and installed so that the to capture and contain the effluent generated in the
cooking process.

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Integrated Approach

Energy savings can be realised with various exhaust

hood applications and their associated make-up air
distribution methods. However with analysis the
potential for increased energy savings can be realised
when both extract and supply for the kitchen are
adopted as an integrated system.

The combination of high efficiency hoods (such as

Capture-Jet hoods) and displacement ventilation
reduces the required cooling capacity, while
maintaining temperatures in the occupied space. The
natural buoyancy characteristics of the displacement
air helps the C&C of the contaminated convective
plume by ‘lifting’ it into the hood.

Third-party research has demonstrated that this

integrated approach for the kitchen has the potential
to provide the most efficient and lowest energy
consumption of any kitchen system available today.

Picture 7. Displacement ventilation

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Kitchen Hoods
The purpose of kitchen hoods is to remove the heat,
smoke, effluent, and other contaminants. The thermal
plume from appliances absorbs the contaminants that
are released during the cooking process. Room air
replaces the void created by the plume. If convective
heat is not removed directly above the cooking
equipment, impurities will spread throughout the
Picture 8. Cooking process
kitchen, leaving discoloured ceiling tiles and greasy
countertops and floors. Therefore, contaminants from convective and latent heat are ‘spilling’ into the
stationary local sources within the space should be kitchen thereby increasing both humidity and
controlled by collection and removal as close to the temperature.
source as is practical.
Capture efficiency is the ability of the kitchen hood to
Appliances contribute most of the heat in commercial provide sufficient capture and containment at a
kitchens. When appliances are installed under an minimum exhaust flow rate. The remainder of this
effective hood, only the radiant heat contributes to the chapter discusses the evolution and development of
HVAC load in the space. Conversely, if the hood is not kitchen ventilation testing and their impact on system
providing sufficient capture and containment, design.

Picture 9. Capture efficiency hoods

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Evolution of Kitchen Ventilation System

Tracer Gas Studies

Halton pioneered the research on kitchen exhaust the heated cooking surface and compared to the
system efficiency in the late 1980’s, commissioning a concentration measured in the exhaust duct. The
study by the University of Helsinki. At the time there difference in concentration was the efficiency at a
were no efficiency test standards in place. The goal given air flow. This provided valuable information about
was to establish a test protocol that was repeatable the potential for a variety of capture and containment
and usable over a wide range of air flows and hood strategies. The Capture JetTM system was tested using
designs. the Tracer Gas technique and the results showed a
significant improvement in capture and containment of
Nitrous Oxide (tracer gas), a neutrally buoyant gas, the convective plume at lower exhaust air flows
was used. A known quantity of gas was released from compared to conventional exhaust only hoods.

Picture 10. Tracer gas studies

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ASTM F1704 system and are used to measure the heat gain to the
In 1990, AGA Laboratories was funded by the Gas kitchen space. This enables researchers to determine
Research Institute to construct a state-of-the-art the temperature of room air being extracted into the
kitchen ventilation laboratory and research the hood.
interaction between cooking appliances, kitchen
In theory, when the hood is providing sufficient
ventilation hoods, and the kitchen environment.
capture and containment, all of the convective plume
In early 1993, the original Energy Balance Protocol
was developed to explain the interaction between the from the appliance is exhausted by the hood while the
heat loads in the kitchen. Mathematically, the energy remaining radiant load from the appliance is heating
consumed by the cooking appliance can only go three up the hood, kitchen walls, floors, ceiling, etc. that are
places: eventually seen as heat in the kitchen.

• to the food being cooked Schlieren Thermal

• out of the exhaust duct
Imaging
• into the kitchen as heat load
Schlieren thermal imaging
has been around since the
In late 1993, this was introduced as a draft standard to
be adopted by ASTM and was called the Energy mid 1800’s but was really
Balance Protocol. The original protocol was developed used as a scientific tool
to only examine the energy interactions in the kitchen starting from the late 20th
with the goal of determining how much heat was century. During the 1950’s
Picture 11. Capture JetTM ON.
released into the kitchen from cooking under a variety Schlieren thermal imaging
of conditions. This standard was adopted by ASTM as was used by AGA Laboratories to evaluate gas
F1704.
combustion with several different burner technologies.
NASA has also made significant use of Schlieren
thermal imaging as a means of evaluating shockwaves
for aircraft, the space shuttle, and jet flows. In the
1990’s Penn State University began using Schlieren
visualisation techniques to evaluate heat flow from
computers, lights, and people in typical home or office
environments. In 1998 the kitchen ventilation lab in
Chicago purchased the first Schlieren system to be
used in the kitchen ventilation industry. In 1999, the
Halton Company became the first ventilation
manufacturer globally to utilise a Schlieren thermal
Imaging system for use in their research and
development efforts.
Figure 3. Capture & containment By using the thermal imaging system we can visualise
all the convective heat coming off an appliance and
Around 1995, the standard adopted new methods of determine whether the hood system has sufficient
determining the capture and containment using a capture and containment. In addition to verifying
variety of visualisation techniques including visual capture and containment levels, the impact of various
observation, neutrally buoyant bubbles, smoke, lasers, supply air and air distribution measures can be
and Schlieren thermal imaging (discussed in more incorporated to determine the effectiveness of each.
detail later in this section). By using this technology a more complete
understanding of the interaction between different
The test set up includes a hood system operating over components in the kitchen (e.g., appliances, hoods,
a given appliance. Several thermocouple trees are make-up air, supply diffusers, etc.) is being gained.
placed from 1.8 m to 2.5 m. in the front of the hood

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Computer Modelling
Computational Fluid
Dynamics (CFD) has been
used in the aerospace and
automobile industries for a
number of years. Recently,
CFD use has become more
widespread, specifically in
the HVAC industry. 30 50 70 100
Figure 4. CFD
CFD works by creating a Airflow (%)

three-dimensional computer
model of a space. Boundary conditions, in the case of Figure 5. Capture efficiency
kitchen ventilation modelling, may include; hood
Consequently, the performances of induction hoods
exhaust rates, input energy of the appliance, supply air
are not due to the delivery of unheated air, but to the
type and volume and temperature of supply air.
improvement in capture.
Complex formulas are solved to produce the final
results. After the solutions converge, variables such as
temperature, velocity, and flow directions can be
visualised. CFD has become an invaluable tool for the
researcher by providing an accurate prediction of
results prior to full scale mock-ups or testing for
validation purposes.

Conclusion of the Test Conducted by EDF:

30 70 80 90 100
The study on induction hoods shows that their capture Airflow (%)

performances vary in relation to the air induction rate.

If this rate is too high (50 to 70%), the turbulence Figure 6. Capture efficiency
created by the hood prevents the efficient capture of
DEFINITION:
contaminants. If the Capture Jet air rate is about 10%
Induction Hood is a concept, which allows for the
or lower, the capture efficiency can be increased by
introduction of large volumes of untreated make-up air
20-50%, which in turn leads to an equivalent reduction
directly into the exhaust hood. The ratio of make-up air
in air flow rates.
to exhaust air was as high as 80%.

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Grease Extraction

The convection plume from the cooking operation

underneath the hood contains grease that has to be
extracted as efficiently as possible. The amount of
grease produced by cooking is a function of many
variables including: the type of appliance used for
cooking, the temperature that food is being cooked at,
and the type of food product being cooked.
The purpose of a mechanical grease filter is twofold:
first to provide fire protection by preventing flames
from entering the exhaust hood and ductwork, and
Figure 7. Total grease emissions by appliance category
secondly to provide a means of removing large grease
particles from the exhaust stream. The more grease
that can be extracted, the longer the exhaust duct and Upon observing figure 7, it appears at first as if the
fan stay clean, resulting in better fire safety. underfired broiler has the highest grease emissions.
From a practical standpoint, grease filters should be However when examining the figure closer you see
easily cleanable and non-cloggable. If the filter that if a gas or electric broiler is used to cook chicken
becomes clogged in use, the pressure drop across the breasts, the grease emissions are slightly lower than if
filter will increase and the exhaust airflow will be you cook hamburgers on a gas or electric griddle. This
lower than designed. is the reason that we are discussing “cooking
operation” and not merely the type of appliance.
What Is Grease? However, we can say that, for the appliances tested in
According to the University of Minnesota, grease is this study, the largest grease emissions are from
comprised of a variety of compounds including solid underfired broilers cooking burgers while the lowest
and/or liquid grease particles, grease and water grease emissions were from the deep-fat fryers. The
vapours, and a variety of non-condensable gases gas and electric ranges were used to cook a spaghetti
including nitrogen oxides, carbon dioxide, and carbon meal consisting of pasta, sauce, and sausage. All of
monoxide. The composition of grease becomes more the other appliances cooked a single food product. It
complex to quantify as grease vapours may cool down is expected that the emissions from solid-fuel (e.g.,
in the exhaust stream and condense into grease wood burning) appliances will probably be on the
particles. In addition to these compounds, same order of magnitude as under-fired broilers, but in
hydrocarbons can also be generated during the addition to the grease, large quantities of creosote and
cooking process and are defined by several different other combustion by-products may be produced that
names including VOC (volatile organic compounds), coat the grease duct. Chinese Woks may have grease
SVOC (semi-volatile organic compounds), ROC emissions well above under-fired broiler levels due to
(reactive organic compounds), and many other high surface temperature of the Woks combined with
categories. the cooking medium utilised for cooking (e.g. peanut
oil, kanola oil, etc.) which will tend to produce extreme
Grease Emissions By Cooking Operation grease vaporisation and heat levels table 4 presents
An ASHRAE research project conducted by the the specific foods cooked for the appliances presented
University of Minnesota has determined the grease in figure 8 and figure 9.
emissions from typical cooking processes. Figure 7
presents total grease emissions for several appliances.

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Appliance Food Product

Gas Griddle Beef hamburgers, 113 g, 120 mm diameter, 20% fat content
Electric Griddle
Gas Fryer French fried potatoes, par-cooked, frozen shoestring potatoes, 60 mm thick with 2.2% fat content.
Electric Fryer
Gas Broiler Beef hamburgers, 150 g, 120 mm diameter, 20% fat content
Electric Broiler
Gas Broiler Boneless, skinless chicken breast, frozen, 1115 g, 125 mm thickness.
Electric Broiler
Gas Oven Sausage pizza with sausage, textured vegetable protein, mozzarella cheese, and cheese substitute. Each slice
Electric Oven was 100 x 150 mm, 142 g.
Gas Range Two pots of spaghetti noodles, 2.266 kg. dry weight, one pot boiling water, two posts of tomato based
Electric range spaghetti sauced, 3 litters each 1.360 kg of link style sausage cooked in a frying pan.
Table 4. Description of food cooked on each appliance

Figure 8. Particulate and vapour grease percentages by appliance Figure 9. Particle size distribution by cooking process
category

The components of grease were discussed earlier and The final piece of information that is important for
a breakdown of the grease emissions into the grease extraction is the size distribution of the grease
particulate and vapor phases is shown in figure 8. particles from the different cooking processes,
presented in figure 9.
Upon examining figure 8, it becomes apparent that
the griddles, fryers, and broilers all have a significant It can be observed from figure 9 that, on a mass
amount of grease emissions that are composed of basis, cooking processes tend to produce particles
particulate matter while the ovens and range tops are that are 10 microns and larger. However, the broilers
emitting mainly grease vapour. If you combine the produce significant amounts of grease particles that
data in figure 7 with the data in figure 8 it becomes are 2.5 microns and smaller (typically referred to as
evident that the broilers have the largest amount of PM 2.5) regardless of the food being cooked on the
particulate matter to remove from the exhaust stream. broiler.

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Cyclonic Grease Extraction Figure 11 presents the extraction efficiency curve for
One non-cloggable design of a baffle type grease Halton’s KSA filter for four different pressure drops
extractor is a “cyclone.’ The extractor is constructed of across the filter.
multiple cyclones that remove grease from the air
stream with the aid of centrifugal force. Filter Removal Efficiency
100
90
80
Figure 10 presents Halton’s KSA grease filter design. 70
You can see the cyclonic action inside the KSA filter. 60
50
40
30
20
10
0
1 2 3 4 5 6 7 8 9 10 11
particle size, microns

2 • 210 l/s – 240 Pa • 110 l/s – 60 Pa

• 150 l/s – 120 Pa • 80 l/s – 30 Pa

Figure 11. Grease extraction efficiency curves for KSA filter 500x330.

Comparison Test Filter Efficiency

3 1
When comparing to the other type of filters on the
market like ‘Baffle filter’, the results below show that
Figure 10. Halton KSA filter Halton has the most efficient filter on the market.
1. air enters through a slot in the filter face
2. air spins through the filter, impinging
Filter Removal Efficiency
grease on the filter walls 100
90
3. the cleaner air exits the top and 80
bottom of the filter. 70
60
50
40
Filter Efficiency 30
20
VDI has set up a test procedure (September 1999) in 10
0
order to compare the results of grease filters from 1 2 3 4 5 6 7 8 9 10 11
particle size, microns
different manufacturer.
• Halton KSA 330, 150 l/s • Other filter type, 110 l/s
• Halton KSA 500, 150 l/s • Baffle filter type, 150 l/s
KSA –filters were supplied by Halton to an Figure 12. Comparison test filter efficiency.
independent laboratory. The fractional efficiency
measurements were made at the flow rates of 80 l/s, Research has shown that as far as efficiency is
110 l/s, 150 l/s and 210 l/s. concerned, slot filters (baffle) are the lowest, followed
by baffle style filters (other type).
Mechanical grease filters quickly lose grease removal Note how the KSA efficiency remains high even when
effectiveness as the particulate size drops below 6 the filters are not cleaned and loading occurs.
microns depending on the pressure drop across the
filters.
Increasing the flow rate from 80 l/s to 210 l/s causes
an increase in the efficiency.

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Ultraviolet Light Technology

Ultraviolet Light – What Is It ?

Light is the most common form of the
electromagnetic radiation (EMR) that the average
person is aware of. Light is only a very small band
within the electromagnetic spectrum. Cosmic rays,
X-rays, radio waves, television signals, and microwave
are other examples of EMR.

EMR is characterised by its wavelength and frequency.

Wavelength is defined as the length from the peak of
one wave to the peak of the next, or one oscillation
(measured in metres). Frequency is the number of
oscillations in one second (measured in Hertz).

Sunlight is the most common source of ultraviolet

Picture 12. UVL with Capture RayTM
radiation (UVR) but there are also many other sources.
UVR emitting artificial light sources can be produced
to generate any of the UVR wavelengths by using the How Does the Technology Work?
appropriate materials and energies. Ultraviolet light reacts to small particulate and volatile
organic compounds (VOC) generated in the cooking
Ultraviolet radiation is divided into three categories – process in two ways, by exposing the effluent to light
UVA, UVB, and UVC. These categories are determined and by the generation of ozone (UVC).
by their respective wavelengths. As is commonly known, the effluent generated by the
Ultraviolet A radiation is the closest to the cooking process is a fatty substance. From a chemical
wavelengths of visible light . standpoint, a fatty substance contains double bonds,
Ultraviolet B radiation is a shorter, more energetic which are more reactive than single bonds. By using
wave. light and ozone in a certain manner, we are able to
Ultraviolet C radiation is the shortest of the three attack these double bonds and consequently break
ultraviolet bands and is used for sterilisation and them. This results in a large molecule being broken
germicidal applications. down into two smaller ones. Given enough reactive
sites, this process can continue until the large
UV technology has been known since the 1800’s. In molecule is broken down
the past it has been utilised in hospital, wastewater into carbon dioxide and
treatment plants, and various industry applications. water, which are
HALTON has now developed new applications to odourless and harmless.
harness the power of Ultraviolet Technology in Unlike the grease that
commercial kitchens. results in these small
molecules, CO2 and H2O
will not adhere to the
duct and will be carried
out by the exhaust air flow.

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This initial concept was studied in detail using a
computational fluid dynamics (CFD) model to
investigate the air flow within the plenum that
holds the UV lamps.

Picture 13. CFD model to investigate the air flow within the plenum that holds the UV lamps.

Evaluation of grease deposition the duct. The plenum design presented utilises an
When the grease generated was used without the UV exhaust airflow rate of 363 L/s with a volume of 0.6
technology, grease did collect on the plates. Tests m3 resulting in an average reaction time of 1.6
showed that using UV technology reduces the grease seconds in the plenum. In order to ensure
deposition on the duct walls and reduces the need for effectiveness under all cooking conditions this is
a restaurant to have their ducts cleaned. recommended as the minimum reaction time in the
plenum. The remaining duct run from the hood to
Evaluation of odour removal - where it exits the building provides a minimum of an
Chemical Analysis additional 0.4 seconds for the ozone to react with the
There was a significant reduction in the measured grease to achieve a total reaction time of 2 seconds.
”peak area” of the chemical compounds.
Results indicate that for cooking French fries, odours Benefits of Halton’s Capture RayTM System
were reduced by over 55% with the UV system. For • Reduces or eliminates costly duct cleaning.
the burgers, the odour was reduced by over 45%. This • Reduces odour emissions.
initial concept was studied in detail using a • Specifically engineered for your cooking
computational fluid dynamics (CFD) model to applications.
investigate the airflow within the plenum that holds • Personnel protected from UV exposure.
the UV lamps. • Monitors hood exhaust flow rates.
• Improved hygiene.
Conclusions • Reduces fire risk.
The results of this research indicate that the UV
technology is effective at reducing both grease
emissions and odour. Based on chemical analysis the
odour was reduced for both the French fries and the
burgers. The grease deposition testing concludes that
there appears to be a reduction in grease build-up in

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Types of Hoods efficiency multi cyclone grease extractor (Model KSA)
is to create a push/pull effect within the capture area,
Kitchen ventilation hoods are grouped into one of two directing the grease-laden vapors toward the exhaust.
categories. They are defined by their respective Performance tests indicate a reduction greater than 30
applications: % in the exhaust rate over exhaust only devices.
TYPE I: Is defined for use over cooking processes that
produce smoke or grease laden vapours and meet the Capture JetTM fan

construction requirements of NFPA-96 Where only small quantities of supply air are available,

TYPE II: Is defined for use over cooking and it is possible to fit a fan to the roof of the supply

dishwashing processes that produce heat or water plenum.

vapour.
Capture JetTM double island hood

Additional information on Type I and Type II hoods can For use over the back-to-back appliance layout. This

be found in Chapter 30 of the 1999 ASHRAE HVAC system incorporates two Capture JetTM hoods, back to

Applications Handbook. This section presents back to cover the cooking line.

information on engineered, low-heat hoods and

commodity classes of hoods as well as an overview of
the most common types of grease removal devices.

Engineered Hood Systems

This subsection presents the engineered hood
products offered by Halton. These systems are factory
built and tested and are considered to be high-
efficiency systems.
These systems have been tested using the tracer gas
technique, Schlieren visualization, and computer
modeling to measure system efficiency. Common to Picture 14. Island model
these designs is the use of Capture JetTM technology
Capture JetTM V bank Island
to improve the capture and containment efficiency of
For use with a single row of appliances in an island
the hood.
configuration. This system incorporates the use of the
Capture JetTM Hoods jets on both sides of the V bank, directing rising heat
These wall style hoods incorporate the Capture Jet and effluent toward the extractors.
technology to prevent ‘spillage’ of grease-laden vapor
Capture JetTM Water Wash
out from the hood at low exhaust rates. A secondary
Water wash systems are often thought of in terms of
benefit coupled with the low-pressure loss, high
grease extraction efficiency. In fact this type of system
has little or no impact on the grease extraction
efficiency of the hood but is a device to facilitate
cleaning of the filters. The basic premise of the water
wash hood is the ability to “wash down” the exhaust
plenum within the hood as well as the mechanical
grease extraction device. A secondary benefit is said
to be an aid to fire suppression. Water wash hoods
come in a variety of configurations as far as hood
geometry goes. These follow fairly closely the “dry”
hood styles.
Picture 9. Capture efficiency hoods

Kitchen Hoods
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 KDG/1309/UK
Picture 17. Exhaust only hood Picture 18. Condensate hood

Design of the exhaust air flow is based upon the face

velocity method of calculation. We generally use 0.2
Picture 15. Water wash hood m/s for a light and 0.4 m/s for a medium cooking load.

Capture JetTM Back Shelf Hood

Condensate Hoods
The Capture Jet back shelf hood incorporates the use
Construction follows National Sanitation Foundation
of jets in a unique way. Due to the proximity to the
(NSF) guidelines.
cooking surface, the jet is used as an air curtain,
A subcategory of Type II hoods would include
extending the physical front of the hood towards the
condensation removal (typically with an internal baffle
cooking surface without impeding the thermal plume.
to increase the surface area for condensation.)
The result from independent testing shows a 27%
decrease in exhaust over conventional back shelf
Heat Removal, Non-Grease Hoods
design during full load cooking and a 51% reduction
These Type II hoods are typically used over non-grease
during idle cooking.
producing ovens. The box style is the most common.
They may be equipped with lights and have an
aluminium mesh filter in the exhaust collar to prevent
large particles from getting into the ductwork.

Other Type of Hoods (Short Cycle)

These systems, no longer advocated by the industry,
were developed when the exhaust rate requirements
followed the model codes exclusively. With the advent
of U.L. 710 testing and a more complete understanding
of thermal dynamics within the kitchen, the use of
short cycle hoods has been in decline. The concept
Picture 16. Back shelf hood
allowed for the introduction of large volumes of
untreated make up air directly into the exhaust hood.
The ratio of make up air to exhaust air was as high as
Basic Hood Type 80% and in some extreme cases, 90%. It was
There are some applications where there is no grease assumed that the balance drawn from the space
load from the cooking process and only small amounts (known as “net exhaust”) would be sufficient to
of heat or water vapor are being generated. Three remove the heat and effluent generated by the
options are presented here depending on the appliances. This was rarely the case since the design
application. did not take into account the heat gain from the
appliances. This further led to a domino effect of
Exhaust Only Hoods balancing and rebalancing the hood that ultimately stole
These type systems are the most rudimentary design air-conditioned air from the dining room. In fact, testing
of the Type I hood, relying on suction pressure and by hood manufacturers has shown that the net-exhaust
interior geometry to aid in the removal of heat and quantities must be nearly equal to the exhaust through
effluent. an exhaust-only hood to achieve a similar capture and
containment performance for short-circuit hoods.

Kitchen Hoods
20
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Hoods Comparison Studies

In this section a variety of techniques and research JetTM technology to enhance hood performance, and
findings are presented that demonstrate the consequently hood efficiency, versus the competition.
performance and value that Halton’s products offer the In this case study, the KVI hood has been modelled
end-user. There is a discussion on the ineffectiveness using CFD software. Two cases were modelled for this
of some hood designs offered by Halton’s competitors analysis: one with the jets turned off – in effect this
followed by a discussion of how capture efficiency simulates a generic exhaust only hood and a second
impacts the energy use, and energy bills, of the end- model with the jets turned on. As can be seen from
user. observing figures 13 and 4, at the same exhaust flow
rate, the hood is spilling when the jets are turned off
KVI Case Study and capturing when they are turned on.
Halton is using state-of-the-art techniques to validate The same studies were conducted in the third party
hood performance. These include modeling of laboratory. The Schlieren Thermal Imaging system was
systems, using CFD, Schlieren imaging systems, and used to visualise the plume and effect of Capture
smoke visualization. All the test results presented here JetTM. As one can see the CFD results are in good
have been validated by third-party research. agreement with the Schlieren visualisation, see
Halton’s standard hood (model KVI) utilizes Capture pictures 19 and 11.

Figure 13. KVI with Capture JetTM off Figure 4. KVI with Capture JetTM on

Picture 19. Schlieren Image of KVI Hood. Picture 11. Schlieren Image of KVI Hood.
Capture JetTM Off Capture JetTM On

Kitchen Hoods
21
 KDG/1309/UK
KVL Case Study models could predict what was observed in a real
Independent research has been performed to evaluate world test. Figures 14 and 15 present the results of
the capture efficiency of Halton’s back shelf style the CFD models for jets off and jets on, respectively.
(model KVL) hood. Note that the jets in the KVL hood are directed
The first set of results for the KVL hood demonstrate downwards, where they were directed inwards on the
the capture efficiency using a Schlieren thermal KVI hood discussed earlier. If you were to place
imaging system. Note that the hood has been downwards directed jets on the KVI hood, it would
manufactured with Plexiglas sides to allow the heat actually cause the hood to spill instead of capture. This
inside the hood to be viewed. Pictures 20 and 21 is testimony to the importance of performing in-house
show the results of the KVL hood with the jets turned research and is just one value added service provided
off and on at the same exhaust air flow, respectively. by Halton.
Once again, it becomes readily apparent that the
Capture JetTM technology significantly improves When you compare the CFD results to those taken
capture efficiency. The KVL hood is spilling with the with the Schlieren system for the KVL hood, you’ll
jets turned off and capturing when the jets are turned note that they produce extremely similar results. This
on. demonstrates that not only can CFD models be used
Another study conducted in-house was to model to model kitchen hoods but they can also augment
these two cases using CFD in order to see if the CFD laboratory testing efforts.

Picture 20. Schlieren Image of KVL hood. Picture 21. Schlieren Image of KVL Hood.
Capture JetTM Off Capture JetTM On

Figure 14. CFD Results of KVL Hood Figure 15. CFD Results of KVL Hood
With Capture JetTM Off With Capture JetTM On

Kitchen Hoods
22
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Ventilated Ceiling
General

The ventilated ceiling is an alternative kitchen exhaust usually assembled from exhaust and supply cassettes.
system. The ceiling should be used for aesthetic The space between the ceiling and the void is used as
reasons when open space is required, multiple kitchen a plenum. The contaminated air goes via the slot
equipment of different types is installed and the where grease and particles are separated.
kitchen floor space is large.
Specific Advantages
The ventilated ceilings are used in Europe especially in • Good aesthetics.
institutional kitchens like schools and hospitals. • Possibility to change kitchen layout.

Ceilings are categorised as “Open” and “Closed” Disadvantages

ceiling system. • Not recommended for heavy load
(gas griddle, broiler..).
• Efficient when only steam is produced.
Open Ceiling
• Not recommended from a hygienic point of
Principle view (free space above the ceiling used as
Open ceiling is the design with suspended ceiling that plenum – risk of contamination).
consists of a supply and exhaust area. • Expensive in maintenance.
Supply and exhaust air ductworks are connected to • Condensation risk.
the voids above the suspended ceiling. Open ceiling is

Picture 22. Open ceiling

Ventilated Ceilings
23
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Picture 23. Closed Ceiling

Closed Ceiling

Halton ventilated ceiling is based on Capture JetTM There are various closed ceilings.
installed flush to the ceiling surface, which helps to Halton utilise the most efficient ceiling, which includes
guide the heat and impurities towards the extract an exhaust equipped with a high efficiency KSA filter,
sections. Supply air is delivered into the kitchen supply air unit and a Capture JetTM system installed
through a low velocity unit. flush to the ceiling panels.
Air distribution significantly affects thermal comfort
and the indoor air quality in the kitchen. Specific advantages
• Draught free air distribution into the working zone.
There are also combinations of hoods and ventilated from low velocity ceiling mounted panels.
ceilings. Heavy frying operations with intensive grease • High efficiency grease filtration using Halton KSA
emission are considered to be a problem for ventilated ‘Multi-cyclone’ filters.
ceilings, so hoods are recommended instead. • Protection of the building structure from grease,
humidity and impurities.
Principle • Modular construction simplifies design, installation
Supply and exhaust units are connected straight to the and maintenance.
ductwork. This system consists of having rows of filter • Integrated Capture Jets within supply air
and supply units; the rest is covered with infill panel. sections.

Panels Panels Panels

Figure 16. Closed ceiling

Ventilated Ceilings
24
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Ceiling Ventilation Testing

The performance of the KCE ventilated ceiling was

studied by the Lappeenranta Regional Occupational
Health institute. The goal was to establish a test
protocol that was repeatable and usable over a wide
range of air flows and ceiling designs.

Tracer Gas Studies

The measurement was carried out with a tracer gas
(N2O) released from the heated cooking surface. The
concentration at different locations (P1, P2, P3, P4)
was observed.
When a steady state of concentration was attained, Figure 17. Tracer gas concentration with Capture JetTM. The right
column without capture air.
the tracer gas was shut off.
Local air quality indices were calculated from the
average breathing zone concentrations and the
concentration in the exhaust duct.

The graphs aside show the concentration at different

measurement points with different air flow rates ( 50,
100, 150%) and with different Capture JetTM air flow
rates.
The column on the left hand side shows the tracer gas
concentration with Capture JetTM and the right column
without capture air.

The study shows that:

The same level of concentration was achieved with
the capture jet ON as with 150% exhaust air flow rate
and Capture JetTM OFF, thus the increase of exhaust
air volume increases only the energy consumption.

• The capture air prevents effectively the impurities

from spreading into the space.
• The use of Capture JetTM is crucial to the proper
function of the ventilated ceiling.

Results
Without Capture Jet™ and with 150% air flow rate the
Figure 18. Concentration study conducted by the Lappeenranta
pollution level is still higher than with Capture Jet™ with regional occupational health institute.
100% air flow rate (see table 5). So it is not possible to
Air flow rate 100% Jets 150% Jets
get the same level even with 150% air flow rate. Measured on (ppm) off (ppm)
values - locations (ppm)
P1 8 19
The revelations are based on the concentrations of the
P2 10 37
occupied zone.
Table 5. IAQ difference

Ventilated Ceilings
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 KDG/1309/UK
Computer modelling Comparison Studies
CFD works by creating a three-dimensional computer Temperature comparison:
model of a space. Boundary conditions, in the case of
kitchen ventilation modelling, may include ; In this case study, the KCE ceiling has been modelled
• Ceiling exhaust rates using CFD software.
• Input energy of appliance As can be seen from observing figures 19 and 20, at
• Supply air type and volume the same exhaust flow rate, the thermal comfort
• Temperature of supply air (lower operative temperature) in the working area is
better when the jets are turned ON.
Complex formulae are used to produce the final
results.
Two cases were modelled for this analysis: one with
the jets turned off and a second model with the jets
turned on.

The cold supply air will close the

ceiling level and so guarentees
comfortable thermal conditions
in the occupied zone.

Figure 19. Capture JetTM ON

The part of the cold supply air is

dropping down in the occupied
zone and it increases the draft
risk.

Figure 20. Capture JetTM OFF

Ventilated Ceilings
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Concentration comparison
As can be seen from observing figures 21 and 22, there is a significant difference
between the Capture JetTM ceiling and the ceiling without the jet.

P3 P4 P2 P1

Figure 21. Capture JetTM OFF - concentrations under the supply units increase

With Capture JetTM off the contaminant is mixed freely with the supply air and the
concentration in the working zone is increased (see table 6).

P3 P4 P2 P1

Figure 22. Capture JetTM ON

The plume from the width of the kitchen appliance is Energy saving effect
bigger. The plume will stay near the ceiling level and In the design process, the main idea is to reach the
the average pollution level is much lower than when set target value of indoor air quality. The enegy
the Capture Jet is OFF. consumption is strongly depending on the target
value. Thus energy consumption and the contaminant
Measured values location Jets on Jets off
level should be analysed at the same time.
(ppm) (ppm)
P1 8 21
Even if the exhaust rate is increased by 50% with no
P2 10 47 Capture Jet concept, it is not possible to reach as low
P3 4 19 contaminant as with the Capture Jet system. For the
P4 5 20 energy saving, this target value approach means that
with the Capture Jet it is possible to reach more 50%
Table 6. Measured concentrations
saving in the energy consumption.
Concentrations measured at each of the points P1, P2,
P3, P4 are about 4 times higher than with jet ON.

Ventilated Ceilings
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 KDG/1309/UK
Recommended Minimum Distances
A minimum horizontal distance between the supply air unit and the edges of
cooking appliances should not be less than 700 mm to ensure that there are no
disturbances (mixing) between displacement air and the convection plume.

If the displacement unit is too close to the heat load from the appliances it can
cause induction. The air from the supply air flow is then contaminated and
reaches the floor.

Duct Installation Requirement

Ventilated Ceilings
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 KDG/1309/UK
Design Guidelines
Design Principles

The design of the professional kitchen follows the

methodology of the industrial design process. The
kitchen layout design and time dependent internal
loads are specified through the understanding of a
specific restaurant and its food service process.
Also, the target levels for the IAQ and ventilation
system performance and the basic concept are to be
defined at an early stage of the design. Picture 24.

In the beginning of the kitchen design process, the affects a person’s capacity to work and at the same
designer defines the type and process type as an time decreases productivity (see curve page 9).
input. The space dimensioning includes room With air conditioning, it is possible to maintain ideal
estimates for all functional areas, such as receiving, thermal conditions all year.
storage, preparation, cooking and dishwashing, that is
required to produce the menu items. The space After that the ventilation strategy of the kitchen space
required for each functional area of the facility is is pre-selected which is one of the key input factors
dependent upon many factors. The factors involved for kitchen hoods selection.
include: The integrated design principle is the key element
• number of meals to be prepared when the exhaust airflow rates are optimised.
• functions and tasks to be performed According to the German guideline (VDI 1999), the
• equipment requirements and application of a displacement ventilation system
• suitable space for traffic and movement allows for a reduction in exhaust air flow by 15%
compared to a conventional mixing ventilation system.
First, the indoor air is selected by the designer Deciding on the strategy in the design phase has a
together with the owner and the end-user. It means great effect on investment costs and the energy costs
an evaluation of the indoor climate including target of the whole system.
value adjustment for temperature, humidity and air Based on the kitchen equipment information such as:
movement. It should be noticed that if there is no air- • heat gain (Sensible / Latent)
conditioning in the kitchen, the indoor temperature is • maximum electrical power
always higher than the outdoor temperature. • surface temperature
The fact remains that when the indoor temperature
and humidity are high ( over 27° C and 65%), this also Hoods are Chosen

Design Guidelines
29
 KDG/1309/UK
Hood Sizing

The size of the exhaust hood in relation to the cooking What Is the Solution
equipment is an important design consideration. Experience has shown that such air draughts can have
Typically, the hood must extend beyond the cooking a much greater effective throw distance to produce a
greater detrimental effect on the capture envelope
equipment: on all open sides for a hood style hood
than one would normally expect.
and on the ends for a back shelf style system.
In a typical situation, if a hood system is not capturing
and containing the effluent from the cooking process,
it will spill in the front corners of the hood.

Picture 27. Right traffic pattern

Picture 25. Wrong traffic pattern

The mouvement of people can involve moving an

object of sufficient size and speed to create
secondary air currents which pirate effluent from
the cooking process.
While the effect of one individual is only
momentary, it can be a problem if the traffic
occurs continually.

Picture 28. Re-hing doors and add end panels

Picture 26. Air draughts

Opening windows in the kitchen creates draughts

and also affects the ideal shape of the thermal
plume.
It can be one of the most difficult problems to
solve. It is difficult because it is often not
suspected as the problem.

Design Guidelines
30
 KDG/1309/UK
Front or Back Overhang - Wrong
Kitchen ventilation hoods require some distance

When the cooking equipment and hood are mounted of overhang on each end of hood.

against the wall, a rear overhang is not required.

However, if the hood is set out in a single island
installation it is necessary to ensure that the proper
distance of back overhang is provided in addition to
the front overhang.

Picture 31. Help! End overhang - wrong

Picture 29. I feel hot!

When two hoods are used in back to back (double

island) installation, the pair of hoods negates the
need for a rear overhang. However, the need for a
front overhang remains.

Picture 30. What’s wrong?

Design Guidelines
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 KDG/1309/UK
Overhang - Right will help insure capture and containment in most
kitchen settings.
All hood type kitchen ventilation requires front and Recommended height from the floor to the lower
end overhangs. In most instances, extending the edge of the hood is 2000 mm.
overhang of a hood system from the typical 300 mm

Picture 32. A wall model installed as an island model. In this case, Figure 23. Wall model KV-/1
overhang on the back is needed.

Picture 14. Island model Figure 24. Island model KV-/2

Picture 33. The hood should extend a minimum of 300 mm Figure 25. End overhang
beyond the cooking equipment.

Design Guidelines
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 KDG/1309/UK
Dishwashing Area
Recommended Overhang

Conveyor type

Figure 26. Conveyor type

Hood type

Figure 27. Hood type

Design Guidelines
33
 KDG/1309/UK
Heat Load Based Design Many manufacturers of commercial kitchen ventilation
It is still common practice to estimate exhaust airflow equipment offer design methods for determining
rate based on rough methods. The characteristic exhaust based on cooking appliances. Any method
feature of these methods is that the actual heat gain used is better than no quantification at all. The method
of the kitchen appliance is neglected. Thus the exhaust of determining exhaust levels based on the heat
air flow rate is the same whether the appliances generated by the cooking process is referred to as
under the hood are a heavy load like a wok or a light heat load based design and is the premise for this
load like a pressure cooker. manual. It is the foundation of accurate and correct
design fundamentals in a commercial kitchen
These rough methods are listed for information, but environment.
should only be used for preliminary purposes and not
The lower the exhaust air flow and the higher the
for the final air flow calculation. They will not provide
exhaust duct temperature at full capture and
an accurate result.
containment the more efficient the hood systems is.
Many designers do not consider hood efficiency. The
• floor area
“box is a box” syndrome is prevalent with many
• air change rate
people. However, each and every hood system, due to
• cooking surface area
internal construction and added performance variables,
• face velocity method (0.3-0.5 m/s)
offers a differing efficiency when related to exhaust
• portions served simultaneously
flows required to obtain capture and containment. This
section discusses the dimensioning of hoods and
Neither of these rules takes into account the type of
gives an in-depth look at heat load based hood design.
cooking equipment under the hood and typically
results in excessive exhaust air flow and hence
oversized air handling units coupled with high energy
consumption rates.

Picture 8. Cooking process

Design Guidelines
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 KDG/1309/UK
The most accurate method to calculate the hood qp = k . (z + 1.7Dh) 35- . Qconv 31- . Kr (1)
exhaust air flow is a heat load based design. This
method is based on detailed information of the Where
cooking appliances installed under the hood including qp – airflow in convective pume, m3/h
type of appliance, its dimensions, height of the z – height above cooking surface, mm
Qconv – cooking appliance convective heat output, kw
cooking surface, source of energy and nameplate
k – empirical coefficient, k = 18 for a generic hood
input power. All this data allows the way the particular Kr = reduction factor, taking into account installation of
appliance emits energy into the kitchen to be cooking appliance (free, near wall or in the corner)
Dh – hydraulic diameter, mm
calculated. Part of this energy is emitted into the
.
space in the form of the convective plume – hot air Dh = 2L+ W
rising from the cooking surface. The other part is L W
rejected into the space by radiation warming up the L,W – length and width of cooking surface accordingly, mm

kitchen surfaces and eventually the air in the kitchen.

LxW

Figure 28. Hydraulic diameter

Kitchen hoods are designed to capture the convective

portion of heat emitted by cooking appliances, thus
the hood exhaust airflow should be equal or higher
than the airflow in the convective plume generated by
the appliance. The total of this exhaust depends on
the hood efficiency.
Picture 34.

qex = qp . Khoodeff . Kads (2)

The amount of air carried in a convective plume over a
cooking appliance at a certain height can be calculated Where
Khoodeff – kitchen hood efficiency.
using Equation
Kads – spillage coefficient taking into account the effect of the air
distribution system on convective plume spillage from under the
hood. The recommended values for Kads are listed in the table 7.

Design Guidelines
35
 The kitchen hood efficiency shown in equation 2 can Hood Engineering Layout Program (HELPTM) is

KDG/1309/UK
be determined by comparing the minimum required specially designed for commercial kitchen ventilation
capture and containment flow rates for two hoods that and turns the cumbersome calculation of the heat load
have been tested using the same cooking process. based design into a quick and easy process. It
contains the updateable database of cooking
Table 7 presents recommended values for the spillage
appliances as well as Halton Capture JetTM hoods with
coefficient as a function of the air distribution system.
enough information to be able to use Equations 1 and
2 accurately to calculate hood exhaust air flow.
For the short-cycle hoods equation 2 will change into
qex = qp . Khoodeff . Kads + qint (2.1) Type of air distribution system Kads

qex = qp
Where .K .K + qint (2.1)
Mixing ventilation
hoodeff ads Supply from wall mounted 1.25
qint – internal discharge air flow, m3/h grills
Supply from the ceiling 1.2
multicone diffusers
The Heat Load based design gives an accurate
Displacement ventilation
method of calculating hood exhaust air flow as a
Supply from ceiling low velocity 1.1
function of cooking appliance shape, installation and diffusers
input power, and it also takes into account the hood Supply from low velocity 1.05
diffusers located in the work area
efficiency. The only disadvantage of this method is that
Table 7. Spillage coefficients as a function of the air distribution
it is cumbersome and time-consuming if manual system
calculations are used.

Total Kitchen Ventilation System Design into the kitchen. This will guarantee that the odours
from the kitchen do not spread to the adjacent spaces.
A properly designed and sized kitchen hood will Equation 3 describes the air flow balance in a kitchen
ensure that effluents and convective heat (warm air)
from cooking process are captured; however, it is not Ms + Mtr = MHood (3)

enough to guarantee the kitchen space temperature is Where

comfortable. The radiation load from appliances Ms – mass flow rate of air supplied in the kitchen (outside supply air
underneath the hood, heat from appliances not under delivered through the air handling unit and makeup air), l/s
Ms = Mosa + Mmu
the hood, people, lights, kitchen shell (heat transfer
Mtr – mass flow rate of transfer air entering the kitchen from the
through walls and ceiling), solar load, and potential adjacent spaces, l/s
heat and moisture from untreated makeup air are to Mhood – mass flow rate of exhaust air through the hoods, kg/s
be handled by the kitchen air conditioning system.
It is recommended that a negative air balance be The supply air temperature ts to maintain design air
maintained in the kitchen. A simple rule of thumb is temperature in the kitchen is estimated from the
that the amount of air exhausted from the kitchen energy balance equation shown below:
should be at least 10% higher than the supply air flow
Ms . cp . ρs (tr – ts) + Mtr . cp . ρtr (tr – ttr) + Qsens= 0 (4)
Where
cp – specific heat of air = 1 kJ/(kg.°C)
ρs, ρtr – air density of supply and transfer air accordingly, kg/m3
tr – kitchen design air temperature, °C
ts – supply air temperature, °C
ttr – transfer air temperature, °C
Qsens – total cooling load in the kitchen, kW from appliance radiation,
unhooded appliances, people, lights, solar load, etc.

Picture 7.

Design Guidelines
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 KDG/1309/UK
In cases where the supply air temperature ts
Number of appliances in use
calculated from equation 4 is below 14°C (13°C off-coil Ksim = (5)
Total number of appliances in kitchen
temperature with 1°C duct heat gain), the supply
airflow rate Ms must be increased. The new value for Kitchen type Simultaneous coefficient Ksim
Ms is calculated from the same equation 4 by setting
Hotel 0.6 – 0.8
ts= 14°C. In this case, we recommend incorporating a Hospital 0.7 – 0.5
return air duct to increase supply air flow. Cafeteria 0.7 – 0.5
School 0.6 – 0.8
Restaurant 0.6 – 0.8
Since it is rare that all the equipment is simultaneously Industrial 0.6 – 0.8
operating in the kitchen, the heat gain from cooking
Table 8. Recommended values for simultaneous coefficient.
appliances is multiplied by the reduction factor called
the simultaneous coefficient, defined in Equation 5.
Recommended values are presented in table 8.

Effect of Air Distribution System same appliances contributing the same heat load to
the space. The supply air flow and temperatures, and
Equation 4 assumes that a mixing air distribution the exhaust air flow through the hoods are the same
system is being utilised and that the exhaust/return air in both cases. The air is supplied through the typical
temperature is equal to the kitchen air temperature ceiling diffusers in the mixing system. In the case of
(assuming fully mixed conditions). Conversely, a the displacement system, air is supplied through
displacement ventilation system can supply low specially designed kitchen diffusers located on the
velocity air directly into the lower part of the kitchen walls. As one can see, the displacement system
and allow the air naturally to stratify. This will result in provides temperatures in the kitchen occupied zone
a higher temperature in the upper part of the kitchen from 22 to 26°C while the mixing system, consuming
while maintaining a lower air temperature in the the same amount of energy as displacement, results
occupied zone. This allows for improvement of the in 27…32°C temperatures. This 2°C temperature
kitchen indoor air quality without increasing the capital increase in the kitchen with the mixing air distribution
costs of the air conditioning system. system will result in approximately 10% reduction in
productivity (see picture 6. page 9).
Picture 35 demonstrates a CFD simulation of two Halton HELPTM program allows kitchen ventilation
kitchens with mixing and displacement ventilation systems for both mixing and displacement ventilation
systems. In both simulations the kitchens have the systems to be designed.

Picture 35. CFD simulation of a kitchen with mixing (top) and displacement (bottom) air distribution system. Air temperatures are shown.

Design Guidelines
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 KDG/1309/UK
Mixing Ventilation
Mixed air supply diffusers supply high velocity air at
the ceiling level. This incoming air is “mixed” with
room air to satisfy the room temperature set point.
Theoretically there should be a uniform temperature
from floor to ceiling. However, since commercial
kitchens have a high concentration of heat,
stratification naturally occurs. Consequently, the
conditioned air does lose some of its cooling
effectiveness, gaining in temperature as it mixes with
the warmer air at the ceiling.

Picture 7. Displacement ventilation

According to VDI 2052, application of a

Displacement Ventilation system allows for a
reduction in hood exhaust airflow by 15%
compared to a conventional mixing system.

Picture 36. Mixing ventilation

Research has shown that if mixing diffusers are

located close to the hood, the high velocity air
interrupts the cooking plume, drawing some of it out
of the hood (in effect causing the hood to ‘spill’) and
further increasing the heat load on the space.

Displacement Ventilation
Thermal displacement ventilation is based on the
natural convection of air, namely, as air warms, it will
rise. This has exciting implications for delivering fresh,
clean, conditioned air to occupants in commercial
kitchens.

Instead of working against the natural stratification in a

kitchen, displacement ventilation first conditions the
occupied zone and, as it gains heat, continues to rise
towards the upper unoccupied zone where it can be
exhausted.

Design Guidelines
38
 KDG/1309/UK
Design Practice

Introduction
It is still quite common practice to estimate exhaust
air flow rates based on rough methods. The
characteristic feature of these methods is that the
actual heat gain of the kitchen appliance is neglected.
Thus, the exhaust air flow rate is the same: even
when a heavy load like a wok or a light load like a
pressure cooker is under the hood. These kinds of
rough estimation methods do not produce optimal
solutions; the size of the whole system will be
oversized and so the investment costs and running Picture 24.
costs will increase.

The layout of the kitchen ventilation design was The steam emitted in the opening of cooking pots or
complex due to the provision of a logical structure the brat pan should also be captured immediately.
combined with good air flow distribution and In this case of providing sufficient efficiency in
performance. capturing polluants, the necessity of having the lowest
energy consumption for the end user had to be
Technically it was a question of designing and considered.
providing an air conditioning installation offering
conditions and a minimal variable temperature in the In tackling these constraints, it has been decided to
surrounding area ie: 23°C, 0/3°C whilst also keeping a select a model of hood using high technology offering,
negative pressure between the kitchen and all for the same connecting power installed in the
adjacent areas. kitchen, maximum efficiency and important energy
savings.
The most sensitive space to be handled turned out to
be the working zone, where the airflow to extract heat Kitchen Design Process
and steam produced by ovens or cooking pots were The design of the professional kitchen environment
important. follows the methodology of the industrial design
process.

Design Guidelines
39
 KDG/1309/UK
Phase1: Background information of the kitchen
available:

• Layout, type and the dimensions of the kitchen. The kitchen is a central kitchen and its layout and
• Type and properties of the cooking equipment dimensions are presented in figure 29.
(sizes, source of energy, input power…).
• Target level for the IAQ and ventilation system • Dimensions of cooking area 11x8.3 - 91m2, 3m high
performance. • five people working in the kitchen
• Temperature design conditions 23°C - Relative
humidity 65% The kitchen is open seven days a week and fourteen
• Total design approach to consider both IAQ and hours a day. Simultaneous coefficient: 0.7.
energy efficiency factors ( air distribution system
chosen).

Figure 29. Kitchen lay-out

Phase 2: Kitchen equipment definition

Item Qty Description Dimensions Elec. kW Gas kW

1 1 Kettle steamer 1200x800x900 18

2 1 Table 500x800x900
3 1 Kettle steamer 1000x800x900 15
4 1 Kettle steamer 900x800x900 14
5 1 Braising Pan 1400x900x900 18
6 1 Braising Pan 1000x900x900 15
7 1 Braising Pan 1200x900x900 18
8 1 Braising Pan 1300x900x900 15
9 1 Table 1000x800x900
10 1 Braising Pan 1300x900x900 18
11 1 Range (4 elements) 800x900x900 16
12 1 Table 1000x800x900
13 2 Fryer 400x800x900 15
14 1 Table 800x800x900
15 3 Convection (double stack) 100x900x1700 17

Table 9. Cooking equipment data-base

Design Guidelines
40
 KDG/1309/UK
Calculation with traditional methods for traditional The amount of air carried in a convective plume over a
hood (KVX type) cooking appliance at a certain height can be calculated
using Equation 1 page 31
One of the rules for hoods is to exhaust between 0.2
of hood face for light duty (boiler, bain marie..) and 0.5 qp = k . (z + 1.7Dh) 35- . Qconv 31- . Kr (1)
for heavy load ( broiler, bratt pan..).
Kitchen hoods are designed to capture the convective
Equation 1 is to calculate the exhaust airflow rate to portion of heat emitted by cooking appliances; thus
determine the volume of air to be extracted: the hood exhaust airflow should be equal to or higher
than the airflow in the convective plume generated by

Q = V . 3600 . P . H (1)
the appliance. The total of this exhaust depends on
the hood efficiency.
Where :
V = capture velocity, m/s qex = qp . Khoodeff . Kads (2)
P = Perimeter of hood, m
H= distance of hood to emitting surface, m Where
Khoodeff – kitchen hood efficiency.
This method does not really take into account the Kads – spillage coefficient taking into account the
characteristics of the appliances. For example, the effect of the air distribution system.
actual heat load (more exactly the convection share of
the sensible load) is neglected. The recommended values for Kads (VDI 1999) are listed
in the table 7 page 38. Based on this table the
Block I: 4200 x 2250 x 555 requested exhaust airflow with wall-mounted supply
Island type hood: (Kads =1.25) is 19 % higher than with low velocity.
Q = 0.3•3600•(4.2+2.25+4.2+2.25)•1.1 = 15 325 m3/h
Since it is rare that all the equipment is simultaneously
Block II: 4200 x 2350 x 555 operating in the kitchen, the heat gain from cooking
Island type hood: appliances is multiplied by the reduction factor called
Q = 0.3•3600•(4.2+2.35+4.2+2.35)•1.1 = 15 563 m3/h the simultaneous coefficient (ϕ). Normally, the
simultaneous factor is from 0.5 – 0.8. This means that
Block III: 4400 x 1350 x 555 only 50 – 80 % of the appliances are used at the
Wall type hood: same time.
Q = 0.25•3600•(4.4+1.35+1.35)•1.1 = 7029 m3/h
Block I:
Total exhaust : 37 917 m3/h A kitchen extraction hood measuring 4200 mm x
2250 mm x 555 mm is mounted 2 m above the floor.
Heat load based design methods The installation height of the hood is then 1.1m above
the appliances.
The most accurate method to calculate the hood
exhaust air flow is a heat load based design. This
method is based on detailed information of the
cooking appliances installed under the hood including
type of appliance, its dimensions, height of the
cooking surface, source of energy and nameplate
input power.
It should be mentioned that with the hood it is
possible to extract only the convection load of the
appliances while the remaining radiant load is always
discharged in the kitchen.

Design Guidelines
41
 KDG/1309/UK
Item1: Kettle steamer

N
Dh – hydraulic diameter, m

2[1.2•0.8]
Dh = = 0.96 m
[1.2+0.8]

Qconv= P. Qs. b . ϕ in W
Qconv= 18. 200. 0.7 . 0.7 = 1764 w L xW

Item5: Braising Pan

= 1160 m3/h

Item2: table: No thermic flow

Dh – hydraulic diameter, m
Item3: Kettle steamer
2[1.4•0.9]
Dh = = 1.095 m
[1.4+0.9]

Qconv= P. Qs. b . ϕ in W
Dh – hydraulic diameter, m
Qconv= 18 . 450 . 0.5 . 0.7 = 2835 w
2[1.0•0.8]
Dh = = 0.888 m
[1.0+0.8] =1557 m3/h

Item6: Braising Pan

Qconv= P. Qs. b . ϕ in W
Qconv= 15.200 . 0.7 . 0.7 = 1470 w

qp = 18 . (1.1 + 1.7[0.96]) 35- . [1470] 3- . 1 = 1013 m3/h

1

Dh – hydraulic diameter, m

Item4: Kettle steamer 2[1•0.9]

Dh = = 0.947 m
[1+0.9]
Qconv= P. Qs. b . ϕ in W
Qconv= 15 . 450 . 0.5 . 0.7 = 2362 w
Dh – hydraulic diameter, m
= 1263m3/h
2[0.9•0.8]
Dh = = 0.847 m
[0.9+0.8]
Item7: Braising Pan

Qconv= P. Qs. b . ϕ in W
Qconv= 14. 80. 0.5 . 0.7 = 392 w
Dh – hydraulic diameter, m

2[1.2•0.9]
Dh = = 1.028 m
= 623 m /h
3 [1.2+0.9]

Qconv= P. Qs. b . ϕ in W
Qconv= 18 . 450 . 0.5 . 0.7 = 2835 w

= 1460 m3/h

Design Guidelines
42
 SUMMARY BLOCK I

KDG/1309/UK
Item Qty Description Dimensions dh (m) Qconv (W) Net exhaust (m3/h)

1 1 Kettle steamer 1200x800x900 0,96 1764 1160

2 1 Table 500x800x900
3 1 Kettle steamer 1000x800x900 0,88 1470 1013
4 1 Kettle steamer 900x800x900 0,847 392 623
5 1 Braising Pan 1400x900x900 1,018 2835 1557
6 1 Braising Pan 1000x900x900 0,947 2362 1263
7 1 Braising Pan 1200x900x900 1,028 2835 1460
TOTAL 7076

Exhaust air flow for block I : Comparison of Exhaust Air flow Rates
Hood exhaust air flow should be equal to or higher Using a heat load based design method gives more
than the air flow in the convective plume generated by accurate and optimized air flow rates than traditional
the appliance. The total of this exhaust depends on rules.
the hood efficiency.

Description Air flow based on Heat load based

face velocity m3/h Design m3/h
Block I 15 325 9610
Block II 15 563 7613
Kads = 1.05
Block III 7029 1867
Kopt = 1.2 – Optimisation of the equipment under Total 37 917 19 070
the hood (In island position always 1.2).
Table 10.
qp = 7076 m3/h

HALTON solution is the recipe for a healthy &

qex = [7076•1•1.05]•1.2+605 = 9610 m3/h
productive kitchen environment
The Heat Load based design gives an accurate
Block II:
method of the calculating hood exhaust air flow as a
A kitchen extraction hood measuring 4200 mm x 2350
function of the cooking appliance’s shape, installation
mm x 555mm is mounted 2 m above the floor. The
and input power, and it also takes into account the
installation height of the hood is then 1.1m above the
hood efficiency. The only disadvantage of this method
appliances.
is that it is cumbersome and time-consuming if
manual calculations are used.
Same calculation procedure as above

Hood Engineering Layout Program, Halton HELP is

specially designed for commercial kitchen ventilation
and turns the cumbersome calculation of the heat load
qex = 7613 m3/h
based design into a quick and easy process. It
contains the updateable database of cooking
Block III:
appliances as well as Halton Capture JetTM hoods with
A kitchen extraction hood measuring 4400 mm x 1350
enought information to be able to use Equations 1 and
mm x 555 mm is mounted 2 m above the floor. The
2 to accurately to calculate the hood exhaust air flow.
installation height of the hood is then 1.1m above the
appliances.

Same calculation procedure as above

qex = 1867 m3/h

Design Guidelines
43
 KDG/1309/UK
Phase 3-4: Kitchen hood design

Intelligent Design Selection by using the HALTON

HELP Software
First of all, Halton had to calculate the air flow
precisely and then measure rates and adjust them
above each appliance. This allows the minimal air flow
that will enable the kitchen to work correctly when
using a KVF hood with Capture JetTM technology to be
determined. Indeed, by introducing air at the front
leading edge of the hood, at high velocity (>4m/s), it
creates a ”Venturi effect “ , leading the air directly
towards the filters, without increasing the exhaust air
flow. Compared with a traditional system of hoods,
the Capture JetTM system allows an exhaust flow up
to 30 % lower, by only having 5-10% of net exhaust.

Figure 32. Halton HELP Air conditioning inputs

Figure 30. Halton HELP Data entry

The KVF has been installed over the cooking Air conditioning calculation results
equipment, Block I and Block II. These hoods are
classified as Island hoods.

Figure 31. Halton HELP Kitchen lay-out

The other KVF hoods are installed over the other

cooking equipment and they are against the wall with
three sides open. These hoods are classified as wall
hoods (Block III) Figure 33. HELP print-out

Design Guidelines
44
 KDG/1309/UK
Energy and Cost Comparison Using the Halton This screen presents the annual heating, cooling and
HEAT Software air conditioning operating costs for the three different
hood types. However, in this case we have only
specified inputs for the Capture JetTM and exhaust only
hoods. Pressing the Conclusion button on the tree
brings up the report seen in figure 36.

This section shows the energy and cost benefits for

the end-user of utilising the Halton Capture JetTM
hood system versus the competition’s exhaust only
and short circuit hoods. The data entry screen for
Halton HEAT software is shown in figure 34.

Figure 35. Halton HEAT Annual costs

The energy savings report presents the financial and

environmental benefits of investing in a Halton
system. In this case, the savings in air-conditioning
were less than the added cost of the Halton hood
providing immediate payback to the end-user. Since
the Capture JetTM hood requires a lower exhaust flow
than a competitor’s hood, less make-up air is required
resulting in a lower air conditioning cost.

Figure 34. Halton HEAT Data entry screen

As shown in figure 35, we are comparing two

systems: a Halton model KVI hood with Capture JetTM
technology versus an exhaust-only hood.
Using Halton HELP software, it can be shown that the
exhaust flow of the Capture JetTM hood is only 19 000
m3/h. The remaining data on the screen are for the
total fan pressure drop of each of the systems
together with the total installed cost for the end-user,
which includes the hoods, fans, labour etc. The final
step on the main form is to press OK and to bring up
the screen shown in figure 35.
Figure 36. Halton HEAT Energy savings report

Design Guidelines
45
 KDG/1309/UK
Being Helped Successfully
Hood type KVF Exhaust-only
It was a quick decision to choose the highly efficient
Fan energy 1755 € 3106 € KVF hood with Halton Capture JetTM technology,
Heating energy 13321 € 20355 €
which allows the hood to operate with up to 30%
Cooling energy 4972 € 7649 €
Total 19958 € 31111 € lower exhaust flows than traditional hood systems.

Table 11. Annual cost

The make-up air for general ventilation is distributed
Upon examining the table above, it becomes apparent directly into the working zone from the front face and
that the KVF hood could save over 11153 Euros in from the low velocity supply diffuser at the side of the
annual operating costs for Paris, France. Using the hood.
exhaust flow rate of 19 000 m3/h of the KVF hood as a It is indeed the only hood currently on the market
basis, the exhaust only hood is calculated to need capable of combining the two features below:
26 905 m3/h.
The net effect is that the payback for the KVF is • Optimising the exhaust air flow rate and
instantaneous. energy saving
• Guaranteeing the comfort of the workers and
improving their productivity with better indoor air
quality.

Improving Comfort

In addition to energy savings there is a net

improvement in comfort due to the decrease in air
volumes calculated (i e : limitation of draughts). Other
features include increase in hood efficiency and high
grease filtration efficiency. The low velocity diffusion of
general supply air via the KVF also helps to improve

Picture 37.
comfort.

Picture 9. Capture efficiency hoods

Design Guidelines
46
 KDG/1309/UK
Product Support Package Tools

Guide
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Halton Hit Design software is an interactive tool that enables you to tion.
select any Halton products you need, configure them, and simulate
and optimise their performance to exactly match your application.

The hallmark of Halton design is the dedication to improve indoor air quality in
commercial kitchens, restaurants, hotels and bars. Halton provides foodservice
professionals is a complete package of tools and material for easy but
sophisticated design of working indoor environments.

• Halton HIT interactive product catalogue

• Halton HELP 3D design and selection software for kitchen hoods and ventilation
systems
• Halton HEAT energy analysis tool for payback time calculation and evaluation of
environmental impacts
• Commercial kitchen design guide
• Detailed technical data for Halton’s kitchen and restaurant ventilation range
• Halton references

Product Support Package Tools

47
 KDG/1309/UK
Measuring Airflow & Balancing Hoods
For any ventilation system to operate properly in a Exhaust & Supply air balancing
commercial kitchen, the airflows have to be measured
and balancing after the system has been installed to Halton offers a variety of means for determining the

ensure that the design criteria have been met. This exhaust flow through their Capture JetTM hoods.

chapter provides information on balancing the supply Integral to all Capture JetTM hoods is the Test &

and exhaust systems in a commercial kitchen. Balance Port (T.A.B.). These ports are to be used in
determining both the exhaust and Capture JetTM air
flows. Each incremental size of hood has been tested
through the range of operable air flows and a curve
has been generated showing air flow as a function of
pressure drop across the T.A.B. Regardless of duct
configuration, the T.A.B. ports will give you an accurate
reading of air flow.

Picture 38. Traditional way

Balancing is best performed when manufacturers of

the equipment are able to provide a certified reference
method of measuring air flows, rather than depending
on generic measurements of duct flows or other
forms of measurement in the field.
Picture 39. Halton way

Fan and Duct Sizing

It is recommended when sizing the exhaust duct not When the fan is installed in the duct system, the
to exceed 9 m/s for the main branch and 7 m/s for the pressure it creates is used to cover the total duct
branch runs. This is due to the noise potential for the pressure loss. The air flow of the fan is determined at
higher velocities and by sizing for a median velocity, it the point where the fan pressure curve and the
gives the designer greater flexibility in changing system pressure curve intersect.
exhaust rates up or down. The ideal duct size is a 1 to A common practice among fan manufacturers is to
1 ratio, trying not to exceed 2:1 whenever possible to use the static pressure in their literature; therefore, it
minimise static pressure and noise. Radius elbows is adequate just to define the static pressure loss in
instead of hard 90° should also be considered for the the ductwork and total airflow to select the fan. Hood
same reason. and grease extractor manufacturers give the pressure
information of these products. The data on frictional
There are two important factors to take into account and dynamic losses of the duct system can be found
when selecting the fan: pressure and sound level. in various sources.

Measuring Airflow & Balancing Hoods / Fan and Duct Sizing

48
 KDG/1309/UK
Fire Safety
The main purpose of fire protection is to protect the
occupants and the fire fighting personnel in case of
fire.
In commercial kitchens the biggest fire hazard exists
in places where a lot of grease is released: fryers, fat
cookers, charbroilers, woks...
The existence of grease and at the same time high
surface temperatures can cause flames and thus
cause the grease to ignite. Fire suppression systems
are used precisely in these cases in many countries.

Whenever fire safety issues are concerned, local

codes have to be taken into account. Picture 40. Fire suppression system

Fire Safety
49
 KDG/1309/UK
Glossary of terms
C & C – capture and containment

CFD – computational Fluid Dynamics

Hood Capture Efficiency - the ability of the kitchen

hood to provide sufficient C&C at minimum exhaust
flow rate

HVAC – Heating, Ventilation, Air Conditioning

Occupied Zone – lower part of the room where people

are, typically 1500 to 1800 mm from the floor.

50
 KDG/1309/UK
References

1. ASHRAE Handbook, Fundamentals Volume. American Society of Heating, Refrigerating, and Air-
Conditioning Engineers, Inc., Atlanta, Ga. 1989.

2 ASHRAE Standard 62-1999, Ventilation for Acceptable Indoor Air Quality. American Society of
Heating, Refrigerating, and Air-Conditioning Engineers, Inc., Atlanta, Ga. 1999.

3. Janssen, J.E., T. Hill, J.E. Woods, and E.A.B. Maldonado. 1982. ÒVentilation for control of indoor
air quality: A case study.Ó Environment International, El 8 487-496.

4. ASHRAE Standard 55-1981, Thermal Environmental Conditions for Human Occupancy. American
Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., Atlanta, Ga. 1981.

5. Verein Deutscher Ingenieure (VDI), Standard 2052: Ventilation Equipment for Commercial Kitchens,
June 1999.

6. Gerstler, William D., Kuehn, Thomas H., Pui David Y. H., Ramsey, James, W., Rosen, Michael,
Carlson, Richard P., Petersen, Sean D., Identification and Characterization of Effluents from Various
Cooking Appliances and Processes As Related to Optimum Design of Kitchen Ventilation Systems,
ASHRAE 745-RP Phase II Final Report, University of Minnesota, revised February 9, 1999.

7. National Fire Protection Association, Standard 96: Standard for Ventilation Control and Fire
Protection of Commercial Cooking Operations, 1998 Edition.

8. National Restaurant Association, 2000 Restaurant Industry Forecast.

9. Code of Federal Regulations, Title 40, Parts 60, Appendix A, Method 5.

10. Gagge, A.P., Burton, A.C., and Bazett, H.D., A Practical System of Units for the Description of
Heat Exchange of Man With His Environment. Science 94: 428-30.

11. ACGIH. Industrial Ventilation – A Manual of Recommended Practice – 1986 Edition. American
Conference of Government Industrial Hygienists, Committee on Industrial Ventilation, P.O. Box
16153, Lansing, MI 48901.

12. Marn, W.L., Commercial Gas Kitchen Ventilation Studies, Research Bulletin No. 90 (March). Gas
Association Laboratories. 1962.

13. Underwriters Laboratories Inc., Standard 710: Exhaust Hoods for Commercial Cooking Equipment,
5th edition, December 28, 1995.

14. EN ISO. International Standard 7730, Moderate Thermal Environments- Determination of the PMV
and PPD Indices and specification of the Conditions for the Thermal Comfort. Geneva, Switzerland.

15. VTT, Research Scientist, VTT automation, Safety Engineering, Tampere Finland.

16. DW/171 Standard for kitchen ventilation systems. Heating and ventilation contractors association,
London 1999.

17. EDF - Electric Appliances and Building technologies - Research and Development division - HE
12/95/044.1995, France.

51
 WWW

www.halton.com/foodservice

Halton Foodservice Contact Information

Visit www.halton.com to find your nearest Halton agency.

Asia Pacific
France Middle-East
Germany India
USA China
Asia Pacific
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Ltd Bhd
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Zone Technoparc Futura Jebel Ali
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60 Zone No.Industrial
101 3580 Fremont
Drive Terraces 浩盾通风设备（上海）有限公司
PT 26064
Persiaran
CS 80102 Teknologi Subang Office/Warehouse
83242 Reit im WinklS3B3WH08 Scottsville,
Lower Ground Floor,
KY 42164 Block 10,NoTeknologi
Persiaran 600 SouthSubang
Xinyuan Rd
SubangBéthune
62402 Hi-Tech Cedex P.O.+49
Industrial Park Tel. Box8640
181168080 4th+1
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270 2375600 Lingang
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Hi-Tech Industrial Park
47500
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(0)1 80Jaya,
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+ 1 270 2375700 Shanghai,201306
47500 Subang Jaya,
Selangor
Fax Malaysia
+33 (0)3 21 64 55 10 United Arab Emirates
info.de@halton.com Bangalore 560 038
info@haltoncompany.com The People’sMalaysia
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Tel. +60 3 5622 8800
foodservice@halton.fr Tel. + 971 (0)4 813 8900
www.halton.de Tel. : +91 80 4112 3697
www.haltoncompany.com Tel.:
Tel.+86
+60(0)21 5868
3 5622 4388
8800
Fax +60 3 5622 8888
www.halton.fr Fax + 971 (0)4 813 8901 Fax: +91 80 4112 3698 Fax:+86
Fax +60(0)21 58688888
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Japan Korea representative
United Kingdom Japan Canada Middle-East
Halton Co. Ltd. Le Meilleur Jongno Town
Halton Foodservice Ltd Halton Co. Ltd. Halton Indoor Climate Halton Middle-East FZE
Hatagaya ART-II 2F #1829 Jongno 1 Ga,
11 Laker Road Hatagaya ART-II 2F Systems, Ltd. Jebel Ali Free Zone
1-20-11 Hatagaya Jongno-gu Seoul,
Airport Industrial Estate 1-20-11 Hatagaya 1021 Brevik Place Office/Warehouse S3B3WH08
Shibuya-ku Korea 110-888
Rochester, Kent ME1 3QX Shibuya-ku Mississauga, Ontario P.O. Box 18116
Tokyo 151-0072 Tel.: +82 2 2075 7990
Tel. +44 1634 666 111 Tokyo 151-0072 L4W 3R7 Dubai
Tel.+ 81 3 6804 7297 Fax: +82 2 2075 7991
Fax +44 1634 666 333 Tel.+ 81 3 6804 7297 Tel. + 905 624 0301 United Arab Emirates
Fax + 81 3 6804 7298 sales@halton.com.my
foodservice@halton.co.uk Fax + 81 3 6804 7298 Fax + 905 624 5547 Tel. + 971 (0)4 813 8900
salestech.jp@halton.com
www.halton.co.uk salestech.jp@halton.com info@haltoncanada.com Fax + 971 (0)4 813 8901
www.halton.jp
www.halton.jp www.haltoncanada.com sales@halton.ae
www.halton.com

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