Grease, Odour, and Smoke Control Equipment

It depends on the type of equipment, volume of cooking and grease levels.  As a rule of thumb, electrostatic precipitators (ESPs) require a service visit every 3-4 months, Techni-clean UV and ozone injection systems need a yearly lamp change and cleaning in between. This keeps the equipment running at maximum performance all of the time.

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Air passes through a high voltage ioniser where the grease and smoke particles are given a positive or negative charge; these charged particles are then collected on the neutral plates of a collector cell.

The maximum operating temperature for an ESP is 60^oC

The pressure drop across and ESP operating at design flow rate is 90Pa (dirty)

95% single pass; 99.75% double pass; 99.99% triple pass

Where possible ESPs should be installed local to the kitchen canopy.

A: For ESPs to work effectively the air passing though the unit needs to support laminar airflow, so the duct connections need to be sized in accordance with DW/144 (22.5-30 degrees). This ensures equal coverage of air across the ESP filters and cells. ESP units should be installed no less than 1 metre away from a bend. Sometimes site constraints mean it is not possible to fit an ESP system local to the canopy, so it is possible to install the ESP externally in a designated plant area.

To fully open the ESP door and remove the ESP collector cells, 600mm is required.

For applications producing high levels of grease and smoke we would recommend double pass ESP filtration.

For applications producing very high levels of grease and smoke we would recommend triple pass ESP filtration

Grease and smoke build up on the collector plates which requires cleaning.  Normally this is every 3-4 months, but this depends on what is being cooked.  Care must be taken when handling the collector cells and they must be cleaned using a non-caustic detergent.  Plasma Clean Air offers a professional maintenance package for ESPs to ensure that they keep performing well.

We generally keep these units in stock but please check with us in advance.

The collector cell, or filter, of an electrostatic precipitator is designed for high efficiency removal grease and smoke particles from kitchen extraction systems.  The grease and smoke would otherwise coat the duct surface requiring TR19 cleaning to prevent fire risk, or would escape outside causing a nuisance to neighbouring properties.

To maintain efficiency, the collector cells need to be cleaned.  The filter cells are normally taken away from site and cleaned by soaking in water containing a non-caustic detergent, cleaned using a high pressure hose and left to dry before being QC tested ready for the next service visit.

The service clean and inspection of electrostatic precipitators is carried out by fully trained Plasma Clean Air service engineers.  They arrive at site with a full set of clean ESP filter cells and use these to replace the dirty cells which are taken from site.  During the service visit, the housing of the ESP is also thoroughly cleaned and electrically inspected to ensure the ESP continues to operate at maximum efficiency.

As the name suggests, the ESP-UV combines an electrostatic precipitator with UV for the control of grease, odour and smoke.  It has a small footprint, ideal for when plant room space is limited and low pressure drop compared to passive filtration systems containing panel, bag, HEPA and activated carbon filters.  As a result, it has low running costs as it doesn’t require as much fan power to pull air through the system.

1100mm

A Rercirculating Tower or recirculating air filtration system is designed for commercial kitchens where it is not possible to extract to the outside.

It is a complete air handling unit incorporating panel, bag, HEPA and activated carbon filters together with a fan. Kitchen air from the canopy is pulled into the tower where it is treated and released back into the kitchen.  It can only be used with electrical cooking equipment, and it is recommended to incorporate air cooling into the kitchen design.

Recirculation towers are suitable for a range of environments such as shopping malls, pop-up kitchens, high rise buildings, basements and where planning permission has been denied.

Please note that Recirculation systems, in accordance with the amended DW172:2020 specification, should have a minimum of 30 air changes per hour background ventilation.

For the system to continue to operate efficiently the filters in a Recirculating Filtration Tower will need to be exchanged when they have reached the end of their lifespan. The frequency of exchange is dependent on the type of cooking as well as the volume of cooking. It is recommended to inspect the system on a regular basis during the first 3 months of installation.

Plasma Clean Air Control Panels are designed to interlock Commercial Kitchen Filtration equipment with air flow.  This prevents the equipment from running when the extraction system is off and stops ozone falling back into the kitchen.   It also saves energy costs by switching the equipment off when the fan is not running.

Plasma Clean Air Control Panels are available in a variety of configurations including Air Flow Interlock, Lamp Life Indicator and Fault Detector options.

Please note that the Xtract series ozone injection units have an inbuilt air flow interlock.

Ozone produced by ozonating UV lamps is pulled into the kitchen extraction system by the main fan.  The ozone then acts on cooking odour by a process known as ozonolysis which breaks down the cooking smells.

All Xtract units create ozone from the air that passes through them.  The new Xtract 2100 v.3, released in January 2025, uses plasma to do this and the other Xtract units use UV light.  The advantage of plasma is that it is a more energy efficient than UV light for the production of ozone.  The plasma modules also enable us to produce lighter and more compact Xtract 2100 v.3 units which are easier to handle and install.

The Xtract 2100 v.3 is 100mm and the Xtract 4200 is 150mm

The Xtract 2100 can handle up to 1.5m³/s; and the Xtract 2100+ can handle up to 2.0m³/s

The Xtract 4200 can handle up to 3m³/s.

If there is insufficient contact time in the duct run, or when you are extracting at low level into a sensitive area

Activated carbon breaks down ozone (O₃) into oxygen (O₂) and is used for ozone control in kitchen ventilation applications.  It is recommended to use a minimum of 0.1s dwell time activated carbon for this purpose either in the form of site-safe discard or cassettes with granular activated carbon.

0.1s when the carbon is acting to remove ozone

Minimum 2 seconds

1 Second

If the air velocity is 6m per second and 2s dwell time is required, the length of duct work will be 6 x 2 = 12m

As close to the kitchen canopy as possible to maximise dwell time for ozone to break down the cooking odour.

Plasma Clean Air’s Xtract ozone injection units are supplied with an in-built pressure differential switch to detect airflow. Ozone injection units should not require a separate control panel for standard use.

As with all equipment, it is recommended to carry out regular inspections during the first few months of installation to understand the impact of the site conditions.

If the air in the environment is highly contaminated, the pre filters will have to be changed often.  Some sites require the prefilters to be exchanged on a monthly basis whereas others require a 3 or 6 monthly exchange.

The ozone tubes require a yearly exchange by trained Plasma Clean Air service engineers.

Ozone alone does not act on grease and smoke particles in the airstream.  For low to moderate grease levels it is recommended to employ a Coil Filter in the canopy.  For high to very high levels of grease and smoke, it is recommended to use an electrostatic precipitator located upstream of the Xtract ozone injection unit.

As well as acting on gaseous odours in the air stream, ozone acts on grease which coats the duct, turning it into a white powder.

Xtract ozone injection units are generally available for next day delivery.

Techniclean Canopy Mount and Techniclean Duct Mounted UV equipment is available.

UV lamps used for kitchen ventilation applications produce high intensity UV light as well as ozone.  UV light attacks grease and gaseous odour molecules by a process known as photolysis and ozone continues to treat grease and odour as it travels through the ductwork.

Techniclean is available as a canopy mounted or duct-mounted UV-C system for odour and grease control.  However if there is a high grease content then it is recommended to use a an electrostatic precipitator in front of the Techniclean Duct Mounted system. This is known as a Combined ESP-UV.

The Techniclean 5000 unit handles up to 1.4m3/s and the Techniclean 7500 unit handles up to 2.1m3/s.

40^oC

50 Pa for a lamp rack only

1 second

0.5 second

If there is insufficient contact time in the duct run, or when you are extracting at low level into a sensitive area

Our standard short frame lamp unit is the Techniclean 5000 measuring 533 H x 1085 W x 220 D; our long frame unit is the Techniclean 7500 measuring 533 H x 1547 W x 220 D

A fine ash builds up on the UV tubes over time, this needs to be removed using a damp cloth which has been soaked in warm soapy water, followed by thorough drying with isopropyl alcohol.  A yearly service is recommended which includes a full lamp exchange.

Techniclean is generally in stock but please check with us in advance.

UV systems are designed for odour and grease control and do not act on smoke particles.  For effective smoke control it is recommended to use an Electrostatic Precipitator.

The Techniclean Duct Mounted UV system is often located in a plant room and requires 1100mm for withdrawal of the lamp rack.

The Techniclean Canopy Mount system is withdrawn through the canopy opening and it is important that an operative can get access safely to the canopy located above the cooking equipment.

Coil filters are installed in the kitchen canopy as a direct replacement for baffle type filters.  They are designed to remove up to 95% of grease particles, dramatically reducing the amount of grease which gets into the extraction system.  This reduces duct cleaning frequency and reduces the maintenance of downstream equipment.

The coils in a Coil Filter cause air to vortex and the oil droplets are spun out of the air stream, coalesce on the coils and collected in the filter.

the CF475 handles 0.34m³/s and the CF375 handles 0.24m³/s

200Pa at the specified air flow rate

Standard sizes are 495mm x 495mm x 45mm, and 395mm x 395mm x 45mm, bespoke filter sizes available on request, please get in touch.

The stainless-steel filter is washed in warm soapy water or in the dishwasher. Depending on the level of cooking, the filter can be washed daily by kitchen staff or as part of a weekly cleaning routine. Remember that the oil trapped by the Coil Filter would otherwise have found its way into the ductwork, increasing fire risk and requiring routine TR19 duct cleaning.

Coil filters do not act on smoke particles.  For effective smoke control it is recommended to use an Electrostatic Precipitator.

Activated carbon is traditionally used for gaseous odour control.  It works by adsorbing odour molecules and is available as granular activated carbon or carbon biscuit used in Sitesafe Discarb filters. It is also employed to remove ozone where it acts as a catalyst to break down ozone (O₃) to oxygen (O₂).

This depends on the type and volume of cooking and t is recommended to inspect the system on a regular basis during the first 3 months of installation.

From our experience, it is common to replace discarb filters every 4 – 6 months when used as the primary method of odour control. For applications where activated carbon is used in conjunction with ozone injection or UV systems in the airstream, we advise that discarb filters are replaced every 9 – 12 months.

Ideally we would recommend canopy mounted Coil Filters and ESP filtration are positioned before carbon filtration to remove grease and smoke particulate to protect and allow effective odour removal via activated carbon as well as prolong the lifespan. Depending on the application fine  filtration media can also be used (Panel, Bag, HEPA filters).

Passive filters include Panel, Bag and HEPA filters for particle capture and Activated Carbon for gaseous odour and ozone control.

Panel, bag and some HEPA filters are relatively cheap compared to Electrostatic Precipitators but they require frequent exchange which means that the ongoing filter and labour costs mount up.  They also have a high static pressure requiring bigger fans and ongoing fan running/energy costs compared to ESPs.