FAQs

Questions relating to Kitchens

  1. Why do kitchen Extract Ducts need cleaning?
  2. How often should I clean my Commercial Kitchen Extract System?
  3. How do you go about cleaning a Kitchen Extract System?
  4. How do you perfom a Kitchen Deep Clean?
  5. What Certificate(s) do I get for Kitchen & Extract / Duct Cleans?
  6. Why should I have Splashbacks?
  7. Why have a Services Distribution Unit?
  8. What is General Ventilation?
  9. Why is Fresh Air Required in the Workplace?
  10. When do I need to Clean my Ventilation System?
  11. Is it Necessary to Clean New Ductwork Before Use?
  12. What Certificate(s) do I get for Air Duct Cleans?

 

Why do kitchen Extract Ducts need cleaning?

Kitchen Extract systems become coated in combustible materials such as fats, grease and soot that are given off during the cooking process.  If these are not regularly removed through cleaning, then the risk of a fire increases as the amount of material deposited increases.

Your insurance company will undoubtedly require you to demonstrate that you are managing this risk appropriately, and that the extract system is cleaned by a company that is "fit for purpose".



How often should I clean my Commercial Kitchen Extract System?

Usage
Frequency of Cleaning
Heavy Use 12 - 16 hours per day Every 3 months
Medium Use 6 - 12 hours per day Every 6 months
Light Use 2 - 6 hours per day Every 12 months

 

How do you go about cleaning a Kitchen Extract System?

  1. Firstly, it it important to determine whether the canopy surface is made from Stainless Steel or Aluminium in order to apply the correct cleaning menthod and chemicals. A simple test with a magnet will confirm which material we are dealing with.
  2. The Grease Filters and any external louvres and cowling are removed for appropriate cleaning which may include dipping in a tank (a "diptank") of degreasing solution.
  3. Next the inside of the canopy and the duct is inspected, and where there is excess grease, this may need to be scraped away before starting chemical cleaning (see item 5 below). In addition, if the duct is inaccessible, then it may be necessary to cut out access panels. If this is required it will have been agreed witht he client prior to work commencing.
  4. Where applicable, the fan is removed and dismantled for cleaning. Once removed, the fan is thoroughly degreased, rinsed and dried.
  5. Now the inside of the canopy and duct can be sprayed with the appropriate chemicals and left to work according to manufacturers' specifications. The entire canopy structure is degreased, and the surrounding back panels, walls and ceiling areas are also thoroughly cleaned.
  6. These surfaces are now cleaned off with a steam vacuum (where possible) or alternatively a steam cleaner, scraper or cloth are used where access is more restricted.
  7. Drip trays and lips are also thoroughly cleaned.
  8. The fan unit is re-assembed and tested.
  9. Grease filters are removed from the diptank after the specified soak time, then steam cleaned and dried before being replaced.
  10. The outside of the canopy is cleaned and sanitised.
  11. Finally, all floors used for access, both inside and outside of the premises are cleaned.


How do you perfom a Kitchen Deep Clean?

To achieve a successful kitchen deep clean, it is important to go about the process in a logical and systematic way.

  1. Firstly, the various appliances need to be dismantled so that their components can be assembled for immersion in a "diptank". A diptank is a vessel which is filled with hot water and a suitable degreaser for the job in hand. Components that can be removed for dipping include; grease filters, oven trays, range tops and rings, fryer pans, grill trays, dismantled fan units as well as other heavily soiled items.
  2. The components are immersed in the diptank, and timed according to the manufacturers' guidelines.
  3. Prior to cleaning the kitchen itself, all electrical items are isolated and exposed switches covered with a waterproof tape of polythene cover. 
  4. Some kitchen items will be best cleaned in an outside area. These are assembled and removed from the kitchen. 
  5. Where possible, equipment is pulled out to ensure that thorough cleaning can be achieved both beneath and behind the equipment. 
  6. The inside areas to be cleaned are now scraped of all excess grease using wire brushes or scrapers, prior to applying an appropriate cleaning solution to the surfaces. Once cleaned, all excess dirt and cleaning chemicals are cleaned off all surfaces. 
  7. Walls and ceilings are normally steam cleaned with a steam vacuum appliance, before the equipment is returned into position. 
  8. Cooking and preparation areas are sanitised. 
  9. Floor areas are then thoroughly cleaned with use of a steam cleaner and wet vacuum. 
  10. Finally, the premises are tidied up - all rubbish and debris is removed, outside areas tidied up. The client is invited to inspect the work and once satisfied sign a customer acceptance form. If we are responsible for locking up, then the site is made secure, and keys returned to the designated place.

 

What Certificate(s) do I get for Kitchen & Extract / Duct Cleans?

Unfortunately, there are currently no universally standard certificates that can be issued in the UK for Kitchen or Extract and Duct cleaning as a guarantee of meeting a consistent standard (as you would get when you take a car for an M.O.T. test, for example).

However, there are number of well documented Standards and Best Practice Guides issues by reputable industry bodies such as the Heating and Ventilation Contractors Association (the HVCA), and members of the HVCA will be able to issue you written confirmation that they have perfomed a job in accordance with a particualr standard, and this may well be in the form of a Certificate.

For example, With the introduction of the Fire Safety Order - the Regulatory Reform (Fire Safety) Order in 2005, it is now the owners and managers of premises who carry the full responsibility for ensuring the safety of building occupants - a role which before October 2006 was effectively carried out by the Fire Authorities by issuing Fire Certificates.

So, with an Extract System, any body with a staff or custom of more than five people has to, by law, complete a Fire Risk Assessment. A component part of that is a certificate to confirm that their Extract including the Duct has been cleaned by a company 'fit for purpose'. The term 'fit for purpose' is now interpreted as at the very least requiring that the cleaning company should be an HVCA member that adheres to the TR/19 standards. To be a member of the HVCA a company has to have been trading for at least three years and pass an independant audit for methods and systems.

Similarly, following other types of cleaning, such as a Kitchen Deep Clean, the cleaning company may issue a certificate stating that the work has been done and saying how long it is valid for, and against which standards the cleaning has been completed. However, as mentioned above, there is currently no single universal standard for this certification.

To conclude, in the absence of proper standardisation, you are best advised to find a cleaning company with a good track record who is a member of a reputable trade organisation such as the HVCA, and who will give a written certificate to confirm that the work they have undertaken follows the most appropriate standards and guidelines. The chances are that your insurance company will require this anyway.


Why should I have Splashbacks?

Some local authorities no longer permit the use of ceramic tiles to the rear of the cookline as these may crack and provide an area for grease ingress as well as a potential harbour of vermin and bacteria.

Stainless steel splashbacks provide an ideal wall covering within food preparation areas where washable surfaces are not only essential but also a pre-requisite of UK health regulations. A properly manufactured and installed stainless steel splashback is extremely easy to keep clean, durable and provides an attractive finish to the kitchen.

Splashbacks should be manufactured from folded and braced stainless steel sheet and the structure behind should be of a suitably fire rated material. The splash-backs should start at approximately 100mm above the floor level, the exact distance is subject to the depth of the floor coving, and should extend up to ceiling level or, up to the underside of a kitchen canopy, where installed. Visible fixings should be kept to the minimum and, where possible, avoided altogether. Openings for electrical or mechanical services may be cut into the splashback to agreed positions. Once installed, gaps between the panels and the building structure should be fully sealed with food grade silicon sealant.


Why have a Services Distribution Unit?

Services distribution units, otherwise known as SDU's are a means of distributing electrical and mechanical services in a covered sealed void from the point of entry in to the kitchen space, to the range of cooking equipment.

SDU's are ideal for separating and enclosing mechanical and electrical services in a stainless steel housing which is aesthetically pleasing. Mechanical and electrical services can be provided to the cooking equipment with ease as they can be designed to accommodate services entry points from high or low levels. From an installation point of view SDU's are ideal because they can minimise co- ordination problems on site, especially if the services are integrally fitted in the factory prior to delivery. From a health and safety aspect, they provide easily cleanable surfaces and easier access between cooking equipment, minimising collection of dirt and grease between or behind the cooking appliances.
They can be also be used to house local an electrical distribution board and components of fire suppression systems.

SDU's can come in a variety of shapes and forms, but normally comprise two vertical columns known as risers and a horizontal run known as a spine running between them. One riser should house the electrical services, while the other should house the mechanical services. Likewise the spines normally consist of two compartments, one for the electrical and the other for the mechanical services runs. The top section of the spine is usually reserved for the electrical services and the lower one for the mechanical services.
SDU's should be configured to suit site constraints and service entry points as well as the equipment layouts. The majority of the SDU's are specified to be fitted to house the electrical and mechanical services where the kitchen appliances are set out in an island configuration, however occasionally they may be required to serve wall mounted ranges.

The most common configuration is the rugby goal post type, 'H' shape, where the services entry point is from high level, followed by the football goal post type, inverted 'U' shape, where the services entry points are from ground level.

The SDU's can also be designed to have both services risers on one end and a supporting leg on the other. Individual risers are also sometimes required to house either the mechanical or electrical services or both.
SDU's should be manufactured from folded and welded type 304 grade stainless steel. If joints are required in the horizontal spines, they should be formed with internal standing seam joints and fitted with stainless steel nuts and bolts. External seams should be sealed with food grade sealant.

The horizontal spine should have a removable lid for access to the electrical compartment fitted with cable trays for installation of electrical wiring. The mechanical services compartment should be fitted with pipework support grid to provide support for the mechanical services. (ie: Gas and water pipes.)
Access panels, screw fixed, should be provided to gain access to the risers and spines as per customer requirements. One hinged access door with quick release latches should be fitted on the mechanical riser to gain access to the gas shut-off valve for maintenance purposes.

Services risers should be provided with adjustable telescopic feet to allow for any discrepancy in floor to ceiling heights or the canopy mounting height as well as uneven floor finish. In cases where services are required to be fitted out; these should be carried out in the factory to save time and problems on site. Competent persons or a specialist company must be employed to carry out the gas and electrical work to comply with the relevant regulations.

In accordance with BS7671, electrical and mechanical services must be separated and must be water tight. In cases where fitting of mechanical services within the electrical spine or riser is unavoidable, special enclosures must be fitted to completely separate the services.

For riser compartments containing gas services, ventilation grilles should be installed both at high and low level in order to prevent any potential gas build-up.

If service distribution units are fitted out 'Knock off' buttons should be positioned, at both ends, in an accessible position near the exit from the catering areas including the risers. This is to comply with DW/172 and BS6173:2001.


What is General Ventilation?

General Ventilation (or dilution ventilation) is a term used to define the flow of air into and out of a working area, for example and office space, so that any contaminants are diluted by adding some fresh air. This can be provided by:

  • Natural ventilation which relies on wind pressure and temperature differences to move fresh air through a building and is usually not fully controllable.
  • Forced or mechanical ventilation which uses mechanical supply and/or extraction to provide fresh air and is controllable.


Why is Fresh Air Required in the Workplace?

You need to provide fresh air to:

  • provide oxygen for breathing in and to remove carbon dioxide from breathing out;
  • remove excess heat or, if conditioned, provide heat (e.g. in winter) and keep a comfortable temperature;
  • dilute and remove body and other types of odours (e.g. food); and
  • dilute any contaminants caused by workplace activities (i.e. the use of dilution ventilation following a risk assessment).

Insufficient fresh air may lead to tiredness, lethargy , headaches, dry or itchy skin and eye irritation in your employees. These symptoms may also be produced whilst working in poorly designed buildings and offices and when there are unsatisfactory working conditions. The symptoms are generally worse in buildings where there is not enough fresh air, or where the fresh air supply may come into contact with contaminats in the air supply system. These are common symptons of what is generally known as sick building syndrome.


When do I need to Clean my Ventilation System?

The Approved Code of Practice to Regulation 6 of the Workplace (Health Safety and Welfare) regulations 1992 requires that any mechanical ventilation systems, including air conditioning systems, which you use to provide fresh air should be regularly and properly cleaned, tested and maintained to make sure they are kept clean and free from anything which may contaminate the air and cause health problems.
As a general rule, if you run your finger along the opening of a duct and it collects dust then it probably needs cleaning. Organisations such as the Heating and Ventilation Contractors Association (HVCA) and the Chartered Institution of Building Services Engineers (CIBSE) provide information on testing for likely contaminants in ductwork and on cleaning. As an HVCA member, Pro-Duct Clean Ltd can also provide you with impartial advice and guidance.


Is it Necessary to Clean New Ductwork Before Use?

Building sites are dusty, dirty places so it is very difficult to prevent any new installation of ductwork from becoming contaminated with the likes of brick, cement and plaster dusts, never mind mineral fibres, forgotten sandwiches and hard hats!

Capping-off the ducts is often used as a potential solution, but even then it is not necessarily fool-proof - and it does add significant additional expense. It is practically impossible to keep ductwork clean by 'capping off'; partly because you have to have the system open in order to erect new duct sections, and that is during the busy, dusty, daytime site working periods. What is more: site people have a strange desire to 'pop' the covers!

The HVCA Guide to Good Practice TR19: 'Cleanliness of Ventilation Systems', aims to provide some clarity.
Firstly, the specifier's need to decide what they want and specify it clearly. Three levels of protection listed in TR19. The third, highest level requires cleaning by a specialist contractor after installation. Given that it is practically impossible to keep ductwork clean by 'capping off', if you want to operate a clean system, then in reality the only objective choice is to specify cleaning.

Secondly, it is important to be clear as to the appropriate measure of cleanliness level for new systems. It is more appropriate to specify against the Post-Clean verification level (0.075g/m2) than using the Surface Deposit Limits ( 6g/m2 for extracts and 1g/m2 for supply and recirculation ducts), since the latter (Surface Deposit Limit) is really a measure of dirtiness, i.e. a 'trigger' level designed to advise when an existing system in use, has become so dirty that it should be cleaned.

So, clearly if you are starting off a new system, you really do need to do a thorough job in minimising the potential for adverse reaction from the new occupants (especially when combined with a cocktail of VOC's off-gassing from adhesives, coatings and other components) is immense, and experienced often enough. You can imagine the frustration of the Facility Manager who has just spent a fortune on building/renting/moving into new premises!

To summarise, the advantages in accepting from the outset of a new build that the system will be professionally cleaned before being brought into use include;

  • You can verify and fine-tune the access system for cleaning
  • You can save a fortune by dispensing with excessive capping off
  • Most importantly in practice, it gives the project people certainty: if a specifier ducks the issue and simply says 'install the ductwork cleanly', without measurable post-clean verification limits to achieve, then who decides what is clean? It's a recipe for under-cutting at tender stage, and conflict throughout the construction and handover stages


What Certificate(s) do I get for Air Duct Cleans?

Unfortunately, there are currently no universally standard certificates that can be issued in the UK for Air Duct cleaning as a guarantee of meeting a consistent standard (as you would get when you take a car for an M.O.T. test, for example).

However, there are number of well documented Standards and Best Practice Guides issues by reputable industry bodies such as the Heating and Ventilation Contractors Association (the HVCA), and members of the HVCA will be able to issue you written confirmation that they have perfomed a job in accordance with a particualr standard, and this may well be in the form of a Certificate.

For example, With the introduction of the Fire Safety Order - the Regulatory Reform (Fire Safety) Order in 2005, it is now the owners and managers of premises who carry the full responsibility for ensuring the safety of building occupants - a role which before October 2006 was effectively carried out by the Fire Authorities by issuing Fire Certificates.

So, with an Extract System, any body with a staff or custom of more tham five people has to, by law, complete a Fire Risk Assessment. A component part of that is a certificate to confirm that their Extract including the Duct has been cleaned by a company 'fit for purpose'. The term 'fit for purpose' is now interpreted as at the very least requiring that the cleaning company should be an HVCA member that adheres to the TR/19 standards. To be a member of the HVCA a company has to have been trading for at least three years and pass an independant audit for methods and systems.

Similarly, following other types of cleaning, such as an Air Duct Deep Clean, the cleaning company may issue a certificate stating that the work has been done and saying how long it is valid for, and against which standards the cleaning has been completed. However, as mentioned above, there is currently no single universal standard for this certification.

To conclude, in the absence of proper standardisation, you are best advised to find a cleaning company with a good track record who is a member of a reputable trade organisation such as the HVCA, and who will give a written certificate to confirm that the work they have undertaken follows the most appropriate standards and guidelines. The chances are that your insurance company will require this anyway.

 

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