Most people know that a commercial kitchen extraction system needs to pull the steam from the cooking line but that is only the start. The system needs to meet several key requirements to be safe, legal and functional.
Canopy Size and Position
The canopy must extend over all exposed sides of cooking equipment by a minimum of 150mm to 200mm and be at the correct height. Typically this would be between 1.8m and 2m from floor level.
Grease Filters
Baffle style grease filters are the normal type of grease filter used in commercial extraction systems. They work by separating grease from the airstream, preventing grease from entering the ductwork. Grease filters are an essential safety component and should be designed to be removable for weekly cleaning. An extraction system that is in operation without grease filters is a fire waiting to happen.
Ductwork Standards
Ductwork runs should be as short as possible and as straight as possible. They should be constructed of rigid steel with sealed joints. Ideally ductwork should be sloped back towards a grease collection point.
Make-Up Air Supply
For every cubic meter of air extracted, the system must then bring in an equal volume of fresh air, to make up for what has been removed from the space. If the system does not have sufficient make-up air then it will create negative pressure, which will draw air in from around the kitchen. In order to try and combat this problem, doors and openings may be sealed, but this will only temporarily solve the problem, as the air will find another route in. If the system is not designed to allow make-up air then the extraction of air will decrease, thus taking the efficiency of the system with it.
Fire Suppression Provisions
Commercial kitchen extraction systems serving heavy cooking equipment should be protected by a fixed fire suppression system covering the canopy and ductwork. Health and safety in catering – a guide for employers published by HSE sets out health and safety in catering as an employer’s duty and deals with fire risk control in the catering environment.
Fan Specification
Fan sizing is based upon the cubic meters per hour (m3/h) of the heat and vapour produced from below the kitchen extraction canopy.
For Commercial Kitchen Extraction, see www.targetcatering.co.uk/kitchen-extraction/commercial-kitchen-extraction.
Getting it right the first time will save you a lot of time and money in the long run.