How often should a commercial kitchen hood be cleaned?
Commercial extractor hood cleaning should be carried out annually as a minimum - unless a Fire Risk Assessment recommends a more frequent maintenance schedule to keep grease and dirt deposits that could increase the chances of a fire breaking our (and spreading quickly). Duct deposits can also breed bacteria, so a thorough cleaning process is equally important for overall food hygiene.
As a rule of thumb, commercial kitchen canopy cleaning should be carried out as often as is necessary to ensure grease deposits never rise above 200 microns (μm).
While most parts of your hood ducting will need expert treatment, such as your filters and air intakes, basic daily and weekly cleaning should also become the norm when it comes to surfaces and easy-to-reach joins. If parts of your canopy/hood duct system reach over 500 microns (hot spots can include the extract plenum), these should be cleaned urgently, regardless of any planned maintenance schedule.
It's worth pointing out that commercial kitchens must be professionally cleaned every six months, with the Health and Safety at Work Act 1974 stating that all outlets must have a cleaning protocol in place. So while annual hood cleaning is a good marker it may be sensible to tie one in with your general deep clean twice a year.
Of course, usage of commercial catering equipment can change seasonally, so it's a good idea to take a micron reading before each clean. This will allow you to determine the ideal frequency - and the best times to put a cleaning visit in the calendar throughout the year.
NB: Insurance companies will also insist on evidence of regular extractor cleaning should you need to make a claim later on, if you can’t provide it they may dispute the claim or even cancel your policy.