Considerations for Kitchen Extract Systems
Kitchen Extract (Exhaust) systems are particularly affected by deposition of grease and oil on internal surfaces from the canopy, including and ductwork, through to the fan and discharge, since no filter can be 100% effective.
Varying efficiencies of filtration in effect vary the rate of fouling.
Likewise, other (non-catering) industrial cooking processes can result in accumulation of grease and oil hidden inside ventilation systems.
Under certain circumstances flame, or high temperature within the duct and canopy, can ignite the grease causing fire to spread rapidly through the duct.
Flame and heat within the duct can ignite surrounding materials at various points along the ductwork path and transfer fire in ways that are difficult to predict and control by kitchen designers, installers, building owners, kitchen operatives and ultimately fire fighters.
There are many cases where a small kitchen fire has be propagated by grease laden extract systems, causing major building destruction and significant business interruption well beyond the confines of the kitchen.
Accumulated grease also provides a hygiene hazard and can lead to foul odour, pest infestation and in some cases unhygienic ‘backwash’ of air into the cooking area.
Leakage of oil from damaged or poorly-installed ductwork can spread these hazards to building areas such as ceiling voids and service shafts.
Legislation & Guidance
Legislation and guidance on standards in buildings is largely oriented towards the design and construction of buildings and associated systems.
Increasingly the proper maintenance of building systems is recognised as crucial to the healthy, economic and safe operation of occupied spaces.
Relevant legislation includes but is not restricted to the following:
- The Regulatory Reform (Fire Safety) Order 2005
- BS9999: 2008 Code of Practice for Fire Safety in the Design, Management and Use of Buildings
- Health and Safety at Work Act 1974
- The Control of Substances Hazardous to Health (COSHH) Regulations
- The Occupiers’ Liability Act 1984
- The Workplace (Health, Safety and Welfare) Regulations 1992 (L24) Regulation 6 for Ventilation.
Why Clean and maintain?
In short is it your responsibility to ensure the safety of people, property and economy. By regularly cleaning and maintaining your kitchen ventilation system you will:
- Reduce the risk of fire
- Prevents the buildup of grease deposits, bacteria of pests within your kitchen. extraction system
- Ensure that you comply with Legislation and Guidance
- Insurance policies will often stipulate clauses relating to proper preventative maintenance and failure to properly maintain systems may cause claims to be affected
How often should I clean?
The frequency of cleaning should be sufficiently frequent that grease deposit limits are not exceeded. In the absence of data on measured levels of cleanliness, time-and-usage-based methods are often used to estimate required cleaning frequency (see table below).
Pre-cleaning micron readings should be taken to enable cleaning frequency to be confirmed as suitable or adjusted accordingly.
How shall you evidence a clean?
The post-clean verification of cleanliness report should assist to serve as evidence of system status to insurance companies representatives, environmental health officers, landlord agents, etc.
On completion of a clean, a report shall be issued including the following:
- The system(s) cleaned
- Pre and post clean Wet Film Thickness Measurements
- Pre and post clean photographic records
- Additional works carried out (if any)
- COSHH data on any chemicals used
- Recommendations for future cleaning requirements
- A sketch or schematic of the system indicating access panels and testing locations and clearly highlighting any un-cleaned/inaccessible areas with an explanation as to why the area could not be accessed/cleaned
- A certificate summarising the cleaning works completed
Latest Update : 21 November 2016