Questions relating to Kitchens

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".

The frequency with which you should have your kitchen extract system cleaned depends on how heavily it is used. Your insurance company will probably specify how frequently they require you to have the extract system cleaned, and they will base this on the HVCA's TR/19 Best Practice guidelines. In practice, the AIB (Association of British Insurers) recommends that, depending on the usage load, an extract system in a commercial kitchen should be cleaned and certified anything from annually to monthly.

The HVCA's TR/19 best practice guidance calls for regular specialist cleaning of Extract Systems based on usage. Section 7.35 shows the minimum recommended interval between specialist cleans to be as below;

See also... a more detailed review of extract canopy maintenance including filter cleaning intervals.

If unattended to, the consequences can be severe for not only the commercial operation but the individual responsible.

Beyond that there are the environmental and mechanical issues that can arise as a result of neglect incomplete cleaning.

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 method 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.

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.

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 performed a job in accordance with a particular 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 independent 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.

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.

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.

In a letter dated 5th July 2010, from Simon Brownlee, Policy Advisor / Environmental Health Officer at the HSE to Mr Gareth Keller, at the Heating and Ventilation Contractors' Association, Mr Browlee wrote:

Thank you for your letter of 7 April 2010 asking for clarification as to whether kitchen extract systems are LEV. Those operating kitchens have a duty under the Control of Substances Hazardous to Health Regulations (COSHH) 2002 to ensure that an assessment of the risks to the health of their employees from exposure to hazardous substances is carried out and that exposure is either prevented or, where this is not reasonably practicable, controlled.

The control measures adopted should be based on the results of the risk assessment and be adequate to control exposure. The COSHH regulations set out a hierarchy of control measures. With regard to airborne contaminants these measures range from totally enclosed processes to the provision of general ventilation. In practice a combination of measures will usually be adopted to effectively control exposure.

It is the view of HSE that kitchen-extract systems are general-purpose work equipment with a number of functions. The objectives of adequate ventilation of kitchens are described in Catering Information Sheet 10(rev 1) Ventilation of kitchens in catering establishments', as including; removing cooking fumes, removing excess hot air; introducing incoming cool clean air; workplace comfort; and providing sufficient air for complete combustion at appliances to prevent the risk of carbon monoxide accumulating.

Whilst these systems can contribute to removal of airborne contaminants they are not designed as LEV and therefore there is no requirement for thorough examination and testing under the COSHH regulations. Duty holders should however ensure that kitchen extract systems are maintained to ensure their effectiveness.

HSE has conducted research into the presence of carcrnogens in cooking fumes. This research shows that small quantities of carcinogens can be found in certain cooking fumes, however further HSE research into levels of ill health concluded that the limited available epidemiological evidence suggested no increased risk of cancer from cooking fumes (in particular lung cancer) among staff in catering kitchens in the UK compared with the population as a whole. Consequently it is HSE's view that installation of local exhaust ventilation in kitchens would be disproportionate to the low risk of exposure to these contaminants.

Yours sincerely
Simon Brownlee