Ventilation Cleaning – it’s all in the process
By Matthew Saunders, National Sales Manager for Air Services
So, you’ve established that your ventilation system requires a clean, and now you have a team coming to the site to clean your system; what should you expect to be happening?
Well, the process can be quite different depending on the size of the system, its use and accessibility and the type of contamination. Our method of cleaning will always be written in an approved method statement and risk assessment, to ensure safety and best practice on site.
Setting Up
Getting kit onto site is the next step. Our team will arrive and follow any site stipulated procedures. This may include, inductions, health & safety briefing, signing in procedures, obtaining permits etc.
We may use different forms of access equipment, such as podium steps, mobile towers or powered access equipment depending on the access requirements. In order to access the internal ductwork surface, we may also need to install access doors, or require a client to organise builders hatches to be fitted before this process.
Read more about installing access doors on our blog here: The importance of the right access door – Swiftclean (UK) Limited
Equipment
Mechanical brushing can be an effective method to clean ventilation systems, but its suitability depends on the specific circumstances of each job. That’s why we conduct a thorough survey of every job that we quote for. We carefully examine the finer details of the task at hand and consider both practicality and efficiency to ensure the best possible outcome, which is a clean and compliant ventilation system.
The process
A mechanical brushing system will agitate all internal surfaces of the ductwork by rotating cleaning brushes at variable speeds all of which rotate clockwise and anticlockwise.
Flexible brushes of varying length, diameter and bristle grade are chosen to suit the duct to be cleaned. Following mechanical agitation, an air lance is used to guide dislodged debris towards an external extract fan for its removal from the system. The extract fan keeps the ventilation system under negative pressure during this process.
Any heavier or more stubborn debris is removed utilising hand scraping, hand vacuuming and wiping to ensure the system is fully clean.
Collection
The extraction system used to create negative pressure, naturally acts as a collection device, whilst the agitation process takes place. The extraction system will filter the extracted air using a Hepa filter to ensure that deposits can be collected.
To clean sections of ductwork at a time, we use foam blocks to isolate sections and prevent cross-contamination.
Verification
On completion of cleaning, you will receive a post-clean verification report as outlined in BESA TR19®. This will include the following:
The ventilation system cleaned
Cleaning methods used
Verification results (if specified)
Pre- and post-clean photographic records
Any faults identified that could impact future hygiene
Additional works carried out (if any)
COSHH data on any chemicals used for cleaning or biocidal treatment
Recommendations for future testing and cleaning requirements.
In addition to the post-clean report, you will have the option to witness any post-clean verification tests taken. We recommend the preferred vacuum test (based on BSEN 15780) where a high-volume air sampling pump capable of drawing 15 l/min through a cassette containing 37 mm matched weight or pre-weighed filters is used to vacuum a 10cm x 10cm area to collect any remaining debris.
The cassette is sent to an independent laboratory for weighing. The results are compared to the post-clean level set for verification of cleanliness ‘following a system clean’, this is far more stringent than that of an existing system and these levels are detailed in section 8 of BESA TR19®. Regardless of system quality class, the post clean test result is not to exceed 0.3g/m2.
And to close…
Finally, depending on the site, we may switch a system back on to ensure all is working ok, or it may be agreed to tape off or block off areas to prevent recontamination, if a system were to be switched back on or other works are taking place.
To book your free survey please get in touch today: 0800 243 471 or email info@swiftclean.co.uk
