Hot Food, Cool Cooks

08 December 2009

Kitchen ventilation design requires co-ordination between consultants in kitchen ventilation, foodservice design and M&E to ensure an energy efficient, fully compliant kitchen also provides a good working environment, as Steve Cole explains

IT WASN’T UNTIL 1999 THAT COMMERCIAL KITCHENS had any specific best practice standards for kitchen ventilation. Before then the industry worked on the basic CIBSE guidelines and various ‘rules of thumb’, or worse still, the ‘it’s what we have always done’ method of design!
The HVCA produced the first standard in 1999 called the HVCA Standard for Kitchen Ventilation Systems DW171. This was updated in 2005 to the current HVCA Specification for Kitchen Ventilation Systems DW172. This document sets out the standards, specifications and best practice guidelines for all aspects of kitchen ventilation design and installation required by a commercial kitchen. Recently CIBSE has produced its latest guide to energy efficient kitchens, TM50:2009, which also refers to the details set out in DW172.
In addition to providing standards for both supply and extract air requirements for the cooking equipment, for which it is most widely referred to, DW 172 also sets out the ventilation requirements of other areas within the kitchen that now must be considered and this may well involve the Foodservice Consultant working closely with the M&E consultants to provide a coordinated ventilation strategy.
Spaces such as the goods in, refuse store, staff changing rooms, dry goods store, preparation areas, dish and pot wash areas and the restaurant servery all need to be ventilated in order to provide a good, safe working environment. The dry goods store, for example, requires 24 hour ventilation that should operate separately from any system that is timer controlled. Refuse areas and chemical stores may also require separate independent ventilation.
The kitchen and restaurant servery ventilation must be coordinated to ensure that cooking smells do not pass into the restaurant seating area or any other occupied areas. Noise from kitchen ventilation system must be considered particularly where kitchens are adjacent to accommodation or office facilities, and within catering teaching facilities.
Energy conservation and sustainability are now a priority and there are now many different technologies available to assist with achieving this aim. These range from simple devices that regulate the cooking equipment supply and extract ventilation according to gas usage through to sophisticated ‘demand’ ventilation and energy management and heat recovery systems that can maximise the potential energy savings. It is now common practice for the Kitchen Ventilation Consultant to work closely with the Foodservice Design Consultant to coordinate the cooking equipment specification and the ventilation strategy in order to achieve the most energy efficient and effective overall kitchen design.
Other issues influence the kitchen ventilation specification such as gas safety compliance, H&S requirements and Environmental Health considerations. In some kitchen installations odour and smoke pollution may be an issue for the surrounding environment. There are various types of technology available that can be incorporated into the ventilation system to deal with these problems such as ultra-violet and ozone filtration systems and smoke filtration units.
It is a general requirement of most planning authorities that kitchen extract ducts are taken to roof level before discharging but there are systems available that can be incorporated into the kitchen extract to enable the exhaust to be discharged at lower levels thus doing away with the need for long duct runs to the roof level.
When it comes to the quality and quantity of the supply air into the kitchen areas, it is generally no longer acceptable to just open the windows. Treated and tempered incoming air must be provided. The supply air system should be designed so as not to create draughts on the staff and it must be interlocked with the extract systemand gas safety controls.
Fire protection is always an important consideration for any commercial kitchen installation and whilst there is currently no mandatory requirement for a fire protection system to be fitted over the cooking equipment, many insurance companies will insist that automatic fire protection equipment is installed.
There are various different types of systems available to suit all types of cooking equipment and ventilation systems and many can interface with the building alarms and BMS controls.
The kitchen operator must carry out a fire risk assessment of the kitchen ventilation system and this will cover cleaning accessibility, procedures and documentation of the cleaning and maintenance schedules and the risk assessment process, etc. If the kitchen ventilation system incorporates enhanced grease removal technology such as ultra-violet filtration this can greatly reduce the grease build up within the extract duct and consequently reduce the fire risk and duct cleaning demands and further contribute to the overall maintenance budget control.
● Steve Cole is an independent consultant and member of FCSI