Case Studies

Case Study No. 1

Laundry extract ventilation system cleaning - A London bank on the Wharf

Our programme incorporated deep cleaning of the laundry extract ducting on a 6 monthly basis. The laundry cleaning was undertaken in June 2005 and contamination levels were heavy and extensive even though the system was only cleaned in May 2005. Investigation into the filters serving the laundry systems at the time of the clean revealed extensive unfiltered air bypass. The filters had been installed poorly and were effectively positioned onto the retaining framework as opposed to inside it. Our engineers removed the filters and changed the arrangements for securing them (previously self tapping screws) so that when next installed they could not be inserted incorrectly. This new arrangement involved fitting an additional securing strip so that the filters would not rattle about within their framework and would provide good dust arrestance and minimize unfiltered air bypass. With these new arrangements in place (subsequent weekly inspections revealed no significant contamination build ups), the 6 monthly cleaning programme remained wholly appropriate.

Case Study No. 2

Kitchen extract ducting - A commercial insurance provider in London

Our programme incorporated quarterly cleaning of one quarter of the entire kitchen extract ductwork system. In effect, all of the ductwork was being cleaned once per annum. The cleaning programme had shown that certain sections of ducting, specifically those close to the canopies, have highlighted a very heavy grease burden after only a few months. However, in general the ducting further than 15 to 20 metres from the canopies are very lightly contaminated and would fall within the 'clean' guidance outlined within HVCA TR/19 The internal cleanliness of ventilation systems. Our cleaning engineers had taken it upon themselves to clean these dirtier sections on a 6 monthly basis in order to minimise the fire risk posed by these sections. The ducting sections further from the canopies are also being cleaned but are generally a quicker process. The following photographs give an indication of the 'before' and 'after' cleaning grease burden within the ducting.

Based on the findings of our completed annual programme, our engineers felt that the 15 to 20 metres of dirtier ductwork sections (specifically 7th floor system (EF9/16), 9th floor island systems (EF 9/19 and 9/21) and 9th floor kitchen system (EF 9/13)) required 3 monthly cleaning with the other systems being cleaned on a 6 monthly basis. The cleaner ductwork (20m + from canopies) would be assessed for cleanliness by measuring the surface grease deposit thickness of the ducting in line with HVCA TR/19 The internal cleanliness of ventilation systems. A report outlining these findings will then be forwarded as documented proof of cleanliness levels. If the findings indicate further cleaning is required, then it will be undertaken as part of a one off project.