New air duct systems are designed to supply or extract a set volumes of air and require regular service to maintain this flow. However over time the regular air-conditioning maintenance service requires additional specialist services to remove contaminates built up within the system that pollute the quality of the indoor air.
The shedding and deterioration of the internal fibreglass insulation is also a substantial problem with older air-conditioning systems. Once the fibreglass commences to breakdown it is then spread throughout the air conditioning system as the fibreglass lining is located past the filters. The shedding material can be made up of fine particles to larger pieces which become lodged in various sections of the ductwork such as turning vanes, baffles and vents. These pieces are normally further broken down by the constant positive air flow and blown out of the room vents.
The consequence of lack of maintenance and cleaning is that the system may not work as designed. If the system, besides transportation of fresh air, also serves to heat/cool the rooms, it might become difficult to regulate and frequently blocks the systems heating and cooling coils. The accumulated dust creates a basis for bacteria and fungi.
Blocked or heavily contaminated filters also create a basis for bacteria and fungi. The traces will over the time grow through and release on the other side of the filter. In this way they can reach the ventilated rooms. This might cause illnesses for the occupants working in the rooms or work area. This indoor air quality (IAQ) problem is commonly referred to as sick building syndrome.
Ventilation systems do not only exist as comfort ventilation in offices, but are also used in industry for the removal of gases, smoke and dust. Many of these extraction systems when working correctly decrease smoke or fumes in the local room or bay. However these systems are often heavily contaminated with the build up in the ductwork and fan assembly and the extraction is markedly reduced or fails completely.
A dirty ventilation duct creates a fire danger. Dust burns very easily, and with suction in the duct system, the fire can spread out to other parts of the building rapidly.