The kitchen extract system presents particular hazards due to the potential for the accumulation of grease. Accumulated grease within an extract system forms a hidden combustion load. Under certain circumstances flame or very high temperature within the duct can ignite the grease causing fire to spread rapidly through the duct.
The Health & Safety Executive and industry and insurance guidance and regulations stipulate that kitchen extract systems should be kept clean to minimise fire and other risks. Your insurers and the environmental health officer will expect you to risk assess and undertake routine and regular inspections and cleaning.
Review of Fire Safety Arrangements – Article 11 of The Regulatory Reform (Fire Safety) Order (RRFSO) (England and Wales) , the Fire (Scotland) Act 2005 and Fire Safety (Scotland) Regulations 2006, and the Fire and Rescue Services (Northern Ireland) Order 2006 and Fire Safety Regulations (Northern Ireland) 2010 require monitoring and review of fire safety arrangements, the management teams of client and contractor shall therefore conduct regular review meetings to ensure that the cleaning frequencies are sufficient to adequately control the grease levels in line with this specification and to adjust frequencies as and when required, thus maintaining suitable fire safety.
The B&ES document TR/19 Third Edition 2019 guidelines ‘Cleanliness of Ventilation Systems’ provides specific guidance on methods of measuring and defining cleanliness as a benchmark for good practice. The frequency of cleaning should be adjusted by means of system testing (inspection and monitoring) so that surface grease deposit limits are not exceeded. The buildings insurance company should be consulted to ensure that the cleaning regime is compliant with the terms of their specific warranty. Any cleaning regime should be justified by a considered risk assessment. (The latest Fire Precautions Workplace and Management of Health & Safety at Work Regulations apply).
Table 4 will assist in establishing the initial cleaning frequency for the system in the absence of data on the historical pre-clean grease thickness levels and duration of days between each set of grease thickness readings
Notes to Table 4
Predictive Accumulation Assessment Table:
In order to quickly assist in selection of the correct cleaning intervals Table 5 assesses the required cleaning intervals against average grease accumulation that has built up over a number of days.
Notes to Table 5
Examples of cleaning methods used, to attain the specified level of hygiene are found in Table 2
Note to Table 2
The techniques employed will be based upon the system type, accessibility, and level of contamination. The cleaning methods listed are considered as best practice. The list is not exhaustive and new technology is being introduced regularly. Therefore, it is critical that the cleanliness result of any method used shall meet the requirements of the post-clean veriﬁcation.
Our post clean reports will be registered on the BESCA VHE scheme, or equivalent recognised scheme, in order to be compliant with TR19®.