Job Type: Commercial Kitchen Extract Cleaning

Site details: Modern cuisine based in an idyllic area and overlooking the Thames Estuary.

Special features: System comprises of one canopy hood (4 x 1 x 0.3)m2 with 6 Baffle grease filters, approximately 5 metre of extract ductwork and a medium size roof mounted fan unit.

Due to the amount of cooking carried out at this site, this system is cleaned annually.


  1. Kitchen Extract Systems have an increased fire, odour, vermin & hygiene risk compared to general supply and extract systems. This is due to the grease build up acting as a potential ignition source, contributed by the heat in the kitchen, possibly elevated oxygen levels from a fresh air supply source and the general deposition of cooking oils on ventilation system components and the ductwork itself acting as fuel.
  2. Wet Film Thickness Tests (WFTT) were carried out at various locations throughout the system, to determine the overall level of grease deposition. Individual readings of over 50 microns are deemed unclean. An average reading across the system of 200 microns or more is deemed unclean. Any individual readings in excess of 500 microns require immediate attention. In accordance with BESA TR19, tests were carried out at the following locations (where accessible).
  3. The WFTT readings pre clean were as follows: Canopy 100 microns, ductwork from canopy 800 microns, fan unit 700 microns.
  4. The work was carried out successfully by degreasing and deep cleaning the canopy, grease filters and the internal surfaces of the associated ductwork.
  5. All areas were thoroughly cleaned with results below 50 microns.
  6. During the cleaning works we discovered that a large section of the riser ductwork contained Flexi-duct. It could not be confirmed if this section was fire rated or not. It was recommended to the client that this section be replaced with appropriate fire rated materials to prevent the spread of Fire.

Before & After Photos

Kitchen Extract Cleaning April 2016 01
Kitchen Extract Cleaning April 2016 02