Why Clean Ductwork?

There is growing concern over the quality of the air we breathe, and for most of us that means a long period of time breathing air supplied to us through air conditioning systems.

If you inspect any air conditioning system after three or four years you will invariably find debris some where in the system . It may just be a light dust build-up but it is there, and the air that you breathe passes through or over it. Add to this the worst situation of vermin decaying in the ductwork and -then the added incidence of damp, and you will have the perfect scenario for the war of bacteria. Yeasts and fungi will grow and multiply and you will breathe it in.

All these situations can arise over years by natural neglect i.e. filters wrongly specified or size changed, frequently missing vermin screens from intakes, badly maintained fan units causing vibration and noise, natural degradation of insulation material (used internally on some ducts) and certainly in acoustic silencers allow excess fibres to migrate into the system. All of this is just the supply system.

I am frequently asked why bother we don’t notice it. Well the legal answer comes under COSHH regulations, Euro directives and the Health and Safety Executive. It is your responsibility to ensure the health and safety of your occupiers whether workers, visitors or tenants. The simplest answer though is probably this, if I was to take a greasy plate then remove some debris from the duct and place it on the plate, then put your breakfast i.e. bacon, eggs -etc. on it, would you eat it? The answer of course would be “NO”, yet every day you are quite content to breathe (or eat) the air that has passed over the same debris in the duct work all through the year. By the same token you would not drink water supplied through a drain pipe, because you see the dirt.

Every time you look at that dirty grille or diffuser, remember you are breathing in that excess dirt and you needn’t. All this is just the supply side.

On the exhaust or extract, well we don’t need to clean this, this is the air being sucked out of the building. Don’t you believe it . We all carry debris with us into the building, fibres from our clothes, minute flecks of paper from our working material, dead skin that we shed all day, and many other types of contamination just in your ordinary office. Then there are the canteen and kitchen environments extracting the above plus oil and grease every day these are in use, resulting in a large build-up of flammable and smelly material lining the ducts. This build-up clogs fire dampers and VCD’s and coats fan blades in large quantities of grease, this further reduces the efficiency and in turn accelerates the problem.

Then there are laundry areas, large quantities of fibres and steam being sucked into the extract, creating not only a fire risk, but without post filtering you, may in certain situations be blowing this unhealthy situation straight into your neighbour’s intake.

I could go on to many other situations i.e. fume extraction – industrial, L.E.D’s etc. but I think that you have got the point. Just because it is not seen it is not acceptable legally or morally to ignore it.

Extract from AEME Pub 3rd Edition