FAQ
2.3. Marquis Intelligence extraction and purification of exhaust air from kitchen hoods
This section explains how Marquis Intelligence designs solutions for the extraction and purification of exhaust air from professional kitchens, where the air contains aerosols, grease particles, smoke, odours, and vapours that may disturb neighbours, damage building façades, or cause other operational issues.
Each solution is designed in accordance with the type of kitchen, its operating regime, and the technical requirements of the building. The goal is to ensure safe and hygienic kitchen operation, stable exhaust performance, and effective odour control, while also maintaining long-term system reliability through planned maintenance.
The purpose of a kitchen exhaust air purification system is to treat the air before discharge into the outdoor environment.
In this way, the system helps reduce odours, aerosols, particles, and smoke.
As a result, it minimizes or eliminates the risk of creating an unpleasant air environment inside the building and in its surroundings.
CONFIRMATION
Marquis Intelligence has extensive experience with facilities where kitchen exhaust air caused complaints and required subsequent engineering interventions.
However, there is also a growing number of new facilities where exhaust air purification is implemented from the very beginning.
Examples include:
No. These systems can be equally effective in renovations and existing buildings.
In such buildings, ventilation ducts, kitchen hoods, and fans may already be installed. However, the actual exhaust air performance may still prove insufficient during operation.
In these cases, odours can return into the building. They can also spread through installations or disturb neighbouring properties.
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Marquis Intelligence has often joined projects as a “second phase” engineering solution. This usually happens after the original exhaust system fails to deliver the expected results.
In such situations, the company’s technical team first performs a diagnostic assessment. Then, it proposes an upgrade or reconfiguration of the existing system.
Examples include certain Delhaize retail facilities, the Delta House canteen, and other similar buildings where clients needed additional air treatment solutions.
No. The kitchen hood and extraction system form the fundamental basis of ventilation in professional kitchens. An exhaust air purification system adds another treatment layer.
It treats the exhaust air before the system releases it into the atmosphere. This upgrade becomes especially important in facilities with higher operational requirements.
These include hotels, densely populated urban locations, sensitive neighbouring environments, and buildings with strict facility management rules.
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In practice, the entire exhaust system must work as one properly designed whole. This includes the kitchen hood, ductwork, air purification system, and exhaust fan.
When engineers design, size, and install all these elements correctly, the system achieves the best results. At the same time, engineers should design the exhaust air purification system according to the real cooking regimes of the kitchen.
In addition, the facility team must maintain the installed equipment properly. This ensures long-term performance and reliability.
From an engineering perspective, it is more accurate to speak about a significant reduction in odours.
This means reducing the concentration of odours, grease particles, aerosols, and vapours. The goal is to bring them down to a level that is acceptable for the specific building and its surrounding environment.
However, the final result depends on several factors. These include the type of food preparation, the kitchen’s operational regime, and the airflow rate.
In addition, the result depends on the type of extraction and exhaust air purification system. Finally, proper system maintenance also plays an important role.
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In its projects, Marquis Intelligence defines target performance parameters.
The company also defines verification methods.
These methods may include internal monitoring and/or independent measurements, when the investor requires them.
Maintenance of kitchen exhaust and exhaust air purification systems is essential.
It keeps the systems functional and efficient.
This matters because kitchen exhaust air carries grease and particles. Over time, these pollutants accumulate on filters and system components.
Maintenance usually includes preventive servicing. This includes inspections, cleaning, and replacement of consumable components. In addition, intervention maintenance may be required when specific problems appear.
The frequency of maintenance depends mainly on the intensity of kitchen operations.
In most cases, facilities use a combined maintenance approach. This means that regular filter cleaning or replacement works as a preventive measure.
However, some system components are replaced only when they reach the end of their service life or fail during operation.
CONFIRMATION
Systems of this type naturally generate a stable service cycle.
For this reason, Marquis Intelligence often contracts maintenance as part of a comprehensive service package.
This package includes preventive and intervention maintenance.
For more information, see:
Maintenance of HVAC and IAQ systems – the pillar of reliability.
Marquis Intelligence first defines the technical solution that best matches the client’s needs.
At the same time, the company reviews all project constraints.
These constraints often include limited installation space, unfavourable air discharge locations, and other technical limitations of the building.
Then, the team defines the input parameters.
It also defines the desired output air quality parameters.
After that, the client receives a technically and economically optimized solution.
When selecting air purification technologies, Marquis Intelligence does not rely on a single treatment method.
Instead, the company uses its 4D Air Purification Model.
This model helps the team calculate and design multi-stage exhaust air treatment systems.
These systems may combine several technologies.
For example, they may include Phoenix systems, by-pass purification concepts, or water-based air treatment systems.
CONFIRMATION
Examples of different technical solutions include several Marquis Intelligence projects.
For the Microsoft canteen kitchen, Marquis Intelligence installed a multi-stage Phoenix purification system.
This system includes mechanical filters of different classes, molecular filters, photo-oxidation modules, an exhaust fan, and an additional heat recovery block.
At the Fantasy kindergarten in Belgrade, Marquis Intelligence implemented a by-pass air purification system.
In the Franš restaurant in Belgrade, the company installed a high-efficiency water-based system for kitchen exhaust air extraction and purification.
Marquis Intelligence can deliver the complete kitchen extraction ventilation system.
This includes ventilation ductwork, kitchen hoods, and associated filtration components.
When a project uses eco hoods, the system also needs fresh air treatment.
It must also supply fresh air into the hood.
This ensures proper hood operation.
At the same time, it maintains stable airflow conditions.
CONFIRMATION
For example, Marquis Intelligence delivered the complete kitchen extraction ventilation system for the charcoal grill at the Franš restaurant in Belgrade.
The project included a false air preparation chamber for the eco hood.
It also included a waste air washing system.
In addition, Marquis Intelligence equipped the system with advanced control through a dedicated control panel.
Yes. Marquis Intelligence performs technical calculations for professional kitchen ventilation systems. The company also prepares the required project documentation.
To carry out this activity, a company must hold Licence 330. This requirement follows the laws of the Republic of Serbia and the applicable technical regulations. Marquis Intelligence holds this licence.
CONFIRMATION
For example, Marquis Intelligence delivered the complete extraction ventilation system for the charcoal grill at the Franš restaurant in Belgrade. The project included a false air preparation chamber for the eco hood.
It also included a waste air washing system.
In addition, Marquis Intelligence equipped the system with advanced control through a dedicated control panel.
It depends on local regulations.
These regulations may differ from country to country.
In addition, many international companies and hotel chains apply their own internal standards.
However, these internal standards must also comply with local regulations.
In general, an exhaust air purification system is not always mandatory.
In the Republic of Serbia, until 2025, the Law on Air Protection required business entities to prevent the spread of odours if their activities could emit them.
This provision appeared in Article 55.
However, the new Law on Air Protection no longer includes this provision.
Nevertheless, the need for exhaust air purification still depends on several factors.
These include the type of kitchen, the volume of exhaust air, the location of the air discharge, and the urban environment.
In practice, facilities most often implement purification systems in higher-risk locations.
These include hotels, restaurants in dense urban areas, shopping centres, office buildings, and other facilities where odours may spread to surrounding spaces.
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In many projects, building management, hotel standards, or user comfort expectations define additional technical or commercial requirements.
For this reason, clients often engage Marquis Intelligence specifically to meet these requirements.
For example, at the Promenada Shopping Centre in Novi Sad, the system had to comply with local regulations.
At the same time, it also had to comply with standards that were applicable in the United Kingdom at that time.
These included:
- GUIDE TO GOOD PRACTICE – Internal cleanliness of ventilation systems (TR19), 2nd Edition, October 2013, Building & Engineering Services Association (BESA)
- DW/172 – Specification for Kitchen Ventilation Systems.
Air generated during food preparation in professional kitchens contains various types of pollutants, including aerosols, grease particles, smoke, odours, and combustion by-products.
If such air is discharged directly into the outdoor environment without proper treatment, several problems may occur, including:
- the spread of unpleasant odours around the building,
- grease deposits on façades and inside ventilation ducts,
- complaints from users or neighbouring premises,
- an increased fire risk caused by the ignition of accumulated grease in ventilation ducts.
For these reasons, modern buildings often implement kitchen exhaust air purification systems that reduce the concentration of particles, aerosols, and odours before the air is released into the atmosphere.
CONFIRMATION
In practice, restaurants, hotels, canteens, and other facilities with intensive and continuous food preparation widely use these systems.
Some of the facilities where Marquis Intelligence has installed exhaust air purification equipment include:
Odours from kitchens can spread into surrounding spaces. That happened when the extraction and air purification system was not properly designed, installed, or maintained.
The most common causes include:
- insufficient air extraction through the kitchen hood,
- inadequate filtration of particles, aerosols, and odours,
- improper positioning of the air discharge outlet in relation to nearby windows or ventilation openings.
In urban environments, where buildings are located close to each other, these issues become even more pronounced. Therefore, it is often necessary to implement additional exhaust air purification systems to prevent odour dispersion.
CONFIRMATION
Marquis Intelligence has been engaged in numerous projects specifically to resolve problems related to the spread of kitchen odours into neighbouring spaces, providing targeted engineering solutions.
In most cases, engineers can significantly reduce or fully resolve smoke and odour issues in existing buildings.
These solutions usually start with optimization of the existing extraction system.
They may also include the installation of:
- additional grease and aerosol filters,
- odour removal technologies,
- multi-stage exhaust air purification systems.
However, each building requires an individual technical assessment.
This assessment helps define the most effective solution under the specific operating conditions.
CONFIRMATION
Marquis Intelligence frequently participates in renovation and upgrade projects for ventilation systems in existing restaurants and commercial kitchens.
Examples include:
- Franš Restaurant, Belgrade,
- MAXI and Shop&Go retail stores (Delhaize),
- Fish&Bar, Belgrade, and many others.
Yes. Kitchen exhaust air purification systems require regular maintenance to maintain their efficiency and reliable operation.
During operation, grease particles, aerosols, and other contaminants accumulate in filters and ductwork. Over time, this buildup can reduce airflow and overall system performance.
For this reason, maintenance typically includes:
- regular cleaning or replacement of filters,
- inspection of fans and ductwork,
- verification of the air purification system’s operation.
The frequency of maintenance depends on the intensity of kitchen use and the type of food being prepared.
CONFIRMATION
In many projects, Marquis Intelligence includes system maintenance as an integral part of the long-term operation of ventilation installations.
You can read more in the Marquis Intelligence blog:
Maintenance of HVAC and IAQ systems – the pillar of reliability.
Kitchen air purification systems are most commonly used in facilities where food preparation generates higher levels of aerosols, smoke, and odours.
These typically include:
- restaurants and cafés,
- hotel kitchens,
- canteens in commercial and industrial buildings,
- kitchens in shopping centres and food court areas.
In urban environments and mixed-use developments, the implementation of air purification systems is often a key factor in maintaining acceptable outdoor and indoor air quality around the building.
CONFIRMATION
Marquis Intelligence solutions have been implemented across a wide range of facilities, including hotels, restaurants, and commercial complexes.
You can explore selected examples in the Marquis Intelligence reference section:
www.marquis.rs/en/#restaurants
Yes. Marquis Intelligence can supply kitchen hoods as part of a complete extraction ventilation system for professional kitchens.
The kitchen hood represents the starting element of the extraction system, as it captures hot and contaminated air generated during food preparation and directs it towards ventilation ducts and air purification systems, after which the air is discharged into the atmosphere.
In professional kitchen ventilation projects, Marquis Intelligence can deliver a complete system that includes:
- kitchen hoods,
- metal filters for grease and particles,
- ventilation ductwork,
- fans,
- exhaust air purification systems, as well as
- additional ducts and all supporting components required for safe and efficient system operation.
The type of kitchen hood is selected based on the type of kitchen, the cooking regime, the available space, and the technical requirements of the building.
CONFIRMATION
An example of an installed kitchen hood can be seen in the project:
Green Heart, Belgrade
Kitchen hoods in professional kitchens can be classified according to several criteria.
First, according to the operating principle, there are:
- conventional extraction hoods,
- eco hoods, also known as double-skin hoods.
Conventional hoods capture air above the cooking zone.
Then, they direct this air through the ventilation system towards the fan and air purification units.
Eco hoods offer a more advanced solution.
They enable the controlled supply of fresh air into the cooking zone.
As a result, they can reduce the total volume of extracted air and improve system energy efficiency.
According to their position within the space, hoods can be:
- wall-mounted hoods,
- island hoods, open on all four sides.
Wall-mounted hoods may be inclined or flat.
They can also be:
- open on one side,
- open on two sides,
- open on three sides.
The selection of the hood type depends on several factors.
These include the layout of kitchen equipment, the type of food preparation, the organisation of kitchen operations, and the volume of the kitchen space.
CONFIRMATION
In its projects, Marquis Intelligence designs and supplies various types of kitchen hoods.
The company tailors each hood to the specific layout, cooking technology, and workflow of the kitchen.
For example, in the “Ketering priča” restaurant, Marquis Intelligence installed multiple hood configurations within a ventilation system project.
These included a central island hood, a wall-mounted hood open on three sides, and a wall-mounted hood open on one side.
This approach ensures that the ventilation system adapts to real operating conditions.
It also provides efficient capture of contaminated air from different cooking zones.
There is no universal solution that is always better for every project.
Eco hoods offer certain advantages, as they enable the controlled supply of air into the cooking zone and can reduce the required airflow rates within the ventilation system. For this reason, they are often used in large professional kitchens and facilities where energy efficiency is particularly important — provided that the kitchen volume and technical conditions allow their application.
On the other hand, conventional hoods are structurally simpler and often represent a reliable and effective solution for smaller kitchens or in buildings where technical conditions do not require more complex ventilation systems.
CONFIRMATION
Marquis Intelligence always analyses the specific conditions of the building and the kitchen’s operating regime before proposing the appropriate hood type and ventilation strategy.
For example, in the Mihajlo restaurant in Belgrade, a highly customised hood solution was designed to meet the unique technical and operational requirements of the space.
Yes. Metal grease filters are a standard component of most professional kitchen hoods.
Their function is to capture a significant portion of grease particles and aerosols generated during food preparation.
As a result, they reduce grease accumulation in ventilation ducts and equipment. This improves system safety and lowers the risk of fire caused by grease deposits.
Metal filters are typically made of stainless steel. They can also be cleaned and reused.
For this reason, they are well suited for professional kitchens with intensive operation.
Marquis Intelligence supplies kitchen hoods and filters according to the specific project requirements and the kitchen’s operating regime.
CONFIRMATION
For the Franš restaurant, Marquis Intelligence supplied certified metal filters as part of the installed hood system. These filters were fire-resistant and flame-retardant.
The same type of filters was also delivered for the “Ketering priča” restaurant in the K District.
At the Green Heart building in Belgrade, Marquis Intelligence installed a hood with standard metal filters.
In that case, the hood was positioned above a dishwashing machine:
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UV lamps of certain wavelengths can break down grease and organic compounds in the air.
However, Marquis Intelligence does not recommend UV lamps in kitchen hoods.
The main reason concerns safety.
Many UV lamps contain mercury.
At the same time, kitchen hoods sit directly above areas where food is prepared.
If a lamp breaks, contamination may occur within the food preparation area.
According to the expert team at Marquis Intelligence, this risk does not align with the core principles of the HACCP system.
Professional kitchens use HACCP, or Hazard Analysis and Critical Control Points, to ensure food safety.
For this reason, Marquis Intelligence gives priority to alternative technical solutions in professional kitchen ventilation projects.
These solutions control aerosols, grease, and odours without placing UV lamps directly in kitchen hoods.
This approach remains preferable even though UV-based technologies are available on the market.
CONFIRMATION
When Marquis Intelligence received a request to supply UV lamps for a kitchen hood in the Fantasy kindergarten in Belgrade, the team analysed alternative solutions.
It also highlighted the risks of such an installation.
Ultimately, Marquis Intelligence implemented a safe by-pass odour reduction system.
This system effectively addressed the problem.
Electrostatic filters are devices for gas purification.
They operate on the principle of electrostatic particle precipitation.
First, high-voltage emission electrodes release ions and electrons.
Then, particles in the gas stream receive an electrical charge.
After that, the electric field attracts these charged particles and deposits them onto collector electrodes.
Originally, engineers developed these devices for flue gas purification in industrial plants.
At the beginning of the 20th century, American chemist Frederick Gardner Cottrell designed the first electrostatic precipitator.
He demonstrated the first practical device in 1906.
Then, in 1908, he received the patent for this technology.
Since then, electrostatic precipitators have become one of the core technologies for removing solid particles from flue gases.
Industries such as power generation, metallurgy, and other industrial processes widely use them.
Over time, engineers have significantly improved the design of these systems.
In particular, they have improved the geometry of emission electrodes and the stability of electrical discharge.
In addition, they have developed better collection electrodes, suspension systems, cleaning mechanisms, and other technical details.
CONFIRMATION
Industry has used electrostatic filters for more than a century to reduce solid particle emissions from flue gases.
Marquis Intelligence designed, supplied, and commissioned a large electrostatic precipitator for flue gas purification from a biomass boiler at the Dijamant industrial complex in Zrenjanin.
This system continues to operate reliably.
It also meets all required emission control measurements.
According to available information, it is one of the largest electrostatic filters installed outside thermal power plants in the Balkans.
An electrostatic filter generates a strong electric field between emission and collection electrodes. It operates at high voltage, typically above 10,000 V.
For this reason, engineers design these devices with a high level of technical precision. Gas containing particles first passes through the ionization zone near the emission electrodes.
In this zone, corona discharge occurs. As a result, the particles become electrically charged. Then, the electric field moves the charged particles towards the collection electrodes.
There, the particles deposit on the electrode surfaces. After a certain period, mechanical rapping or another electrode cleaning method removes the accumulated particles.
System efficiency depends on several factors, including:
- particle size,
- electrical properties of the particles,
- gas flow velocity,
- moisture content of the gas.
CONFIRMATION
Modern electrostatic filters use negative emission electrodes.
This configuration enables more stable corona discharge and better control of the ionization process.
Over time, engineers have significantly improved electrode design.
Early systems used tensioned wires.
In contrast, modern systems use rigid electrodes with multiple emission points.
This design ensures more stable and efficient operation of the device.
Although DW/172 – Specification for Kitchen Ventilation Systems gives certain limitations, electrostatic filters still appear in professional kitchen ventilation projects.
According to DW/172, electrostatic filters do not guarantee removal of particles smaller than approximately 0.3 µm.
The guideline also notes their limited effectiveness in odour reduction.
However, DW/172 does not prohibit their use.
Instead, it states that systems with electrostatic filters must include additional filtration stages and odour control elements.
For this reason, kitchen ventilation systems do not use electrostatic filters as a standalone solution for exhaust air treatment.
Instead, they usually use them as a pre-filtration stage within a multi-stage air treatment system.
CONFIRMATION
DW/172 – Specification for Kitchen Ventilation Systems is one of the key specialised technical guidelines for professional kitchen ventilation and exhaust air treatment.
For example, compliance with this standard was a requirement at the Promenada Shopping Centre in Novi Sad.
Marquis Intelligence implemented the solution for this project.
Within DW/172, electrostatic filters appear as components that may form part of ventilation systems.
However, the document notes that they do not provide guaranteed emission values or reliable odour reduction.
Therefore, additional filtration and air treatment technologies are recommended.
In several projects, Marquis Intelligence upgraded existing extraction and air treatment systems where electrostatic filters had already been installed.
Many of these projects started because of odour complaints.
When space conditions allowed it, Marquis Intelligence kept these devices as pre-filters within the filtration system.
In such cases, the replacement frequency of main filters decreased.
This confirmed their supporting role in reducing the load on primary filtration stages.
Moisture content can significantly affect the efficiency of electrostatic filters.
In professional kitchens, exhaust air often contains a high level of water vapour.
This vapour comes from several sources, including:
- cooking processes,
- thermal food preparation,
- dishwashing activities.
At the same time, kitchen exhaust air also carries grease aerosols.
When moisture combines with grease aerosols, sticky deposits can form on electrodes and collection plates.
These deposits reduce the efficiency of the electrostatic precipitation process.
In addition, they can make stable system operation more difficult.
For this reason, professional kitchen ventilation systems require proper design and regular maintenance.
In practice, engineers often add extra filtration stages and supplementary air treatment equipment.
This helps ensure stable operation in conditions with high humidity and grease-laden air.
CONFIRMATION
Practical experience from professional kitchen ventilation systems confirms this.
The kitchen’s operating regime, the quantity of grease aerosols, and the moisture content of the air all strongly affect system stability.
They also affect maintenance requirements.
The efficiency of electrostatic filters depends heavily on clean emission and collection electrodes.
In industrial applications, electrostatic filters often use automatic electrode cleaning systems.
These systems may clean the electrodes at very short intervals, for example every 3–5 minutes.
However, professional kitchen environments usually cannot support such operating and maintenance regimes.
Therefore, engineers commonly implement additional filtration stages and alternative technical solutions.
This approach helps ensure reliable and stable system performance.