It is a legal requirement to provide fresh or purified air in an enclosed workspace and to maintain the component parts are the system that provides that air. Many insurance policies will specify that system maintenance be carried out in accordance with TR19 by trained persons.

The importance of a rigid ventilation hygiene regime was also highlighted during the COVID pandemic there was a risk of infection through poorly maintained systems. Poorly maintained ductwork has an impact on a buildings indoor air quality which increases sick days for occupants and reduces productivity.

We follow the BESA (Building and Engineering Services Association) TR19 (AIr) “Internal Cleanliness of Ventilation Systems” rigidly and our lead engineers are trained as a minimum to BESA Air Hygiene Technician standard.  That specification clearly outlines what is required of us as your air hygiene provider to ensure that our work and your systems are compliant.

TR 19 outlines good practice for maintaining the cleanliness of ventilation systems, this includes:

• The acceptable levels of dust in new and existing ductwork systems, for supply, extract and recirculated air
• Access panel locations for cleaning
• Specific requirements for maintenance of system components
• Inspection and sampling methods
• Cleaning methods
• Post clean verification

Process

Initial Consultation

We will attend your site and conduct a full system survey that will include size of extract canopies, canopy filter details, ducting lengths and layouts, plant and inlet/exhaust point types and locations.

Quotation

We will produce a quotation based on our system survey that will include the data from the survey and a basic schematic of the system that identifies the system components.  This survey will highlight any requirements for additional access panels, concealed components due to the fabric of the building and areas perceived as inaccessible for our initial clean.  The quotation will also show a scope of works detailing how we will clean the components of your ventilation system.  Large or complex system may require you to provide us with the as fitted drawings for the system or we may have to charge for a detailed survey which would be deducted from the quotation for cleaning.

Validation of the cleanliness of your system can be achieved by preferred vacuum test (PVT) or deposit thickness test (DTT) and can be combined with microbiological surface sampling.  We will discuss the most suitable validation methods for your systems during our initial consultation and the selected methods will form part of your quotation.

Disinfection of a system can be achieved post clean by “fogging” the system which is the spraying/injection of chemicals in the ductwork system to reduce microbial levels.  We will discuss your requirements for disinfection during our initial consultation and the results of that discussion will form part of your quotation.

Initial Clean

Prior to commencement on site we will provide your site representative with details RAMS for the duration of the works and our requirements to maximise the effectiveness of the clean.

Once on site our engineers will then:

• Fit access doors if identified during the quotation process
• Clean all accessible components of your ventilation system
• Disinfect your system as specified in your quotation
• Take validation readings as specified in your quotation
• Take evidential photographs to support the validation readings pre and post clean
• Produce electronic report

Reporting – Using our reporting software the engineer will produce a TR19 report for cleaning verification.  Unlike grease extraction cleaning BESA does not have a published report format, but we follow the same intensive reporting format as TR19 grease. Our reports include:

• An executive summary page that highlights the key risks
• A clear “Yes” or “No” as to whether the system was cleaned in its entirety
• If “No” to the above question, the reason why it was not cleaned in its entirety and a suggested solution
• Other hazards that have been identified
• Validation readings for the test locations
• The mean validation reading across the system – (AHUs treated as separate entity)
• The current cleaning frequency
• A recommendation of a new cleaning frequency based on the validation results
• Before and after photographs to match the validation test points
• A schematic diagram of the system layout showing the system that has been cleaned and any areas that could not be cleaned
• Validation locations identified on the schematic