Ventilation duct inspection is a specialised task that usually requires specialist equipment and experienced operators that have been trained extensively in the proper inspection methods for ventilation ducting.
Ventilation ducting can be found in use in many different industries and public sector buildings, such as the oil and gas industry, the chemical industry, schools, hospitals, libraries, museums, etc.
All of the ducting requires inspection at regular time periods to ensure efficient operation and also to ensure that good quality air is being circulated throughout the building. It should always be borne in mind that the primary function of ventilation ducting is to transport clean air to the various rooms and chambers of a building.
Poorly maintained ventilation ducting can lead to many problems. These include an increased risk of fire because of debris build up, dirty filters causing the breeding of bacteria and fungus, as well as a quality of air that is below the acceptable standard. Dust and loose corrosion parts can also reduce the efficiency of the system and can impact negatively in the longer term.
A proper ventilation duct inspection usually starts with an on-site visit to assess the situation. An alternative way is to examine accurate design drawings to assess the heating, ventilating, and air conditioning (HVAC)ducting layout. Once the initial assessment has been made, the work team can plan how to tackle the actual cleaning of the HVAC ducting.
The ventilation duct inspection is usually performed by remote camera. A mini digital camera system can be introduced into the ducting and its progress controlled remotely by an operator. The interior of the HVAC ducting can be examined in minute detail and debris and dirt can be seen, as well as corroded parts that may require attention. The journey taken by the remote camera system can be recorded as a video that can be examined at leisure later.
There are three basic methods in use for the cleaning of ventilation ducting. The contact method uses a vacuum device to clean it in a more conventional way, sucking in the debris and dust and removing it from the ducting. The air sweep method uses compressed air to dislodge built up debris and dirt. This is then swept along the ducting to be vacuumed up by a secondary system in place. The mechanical brush method uses a rubberised circular brush to dislodge debris and dirt and sweep it along the ducting where it again can be vacuumed up and removed by a secondary system.
The contact method tends to be the most effective for cleaning ventilation ducting, though the other methods work well too. The effectiveness of a cleaning operation is of course dependent to a large degree on the type of materials that the ducting is made from. The old fibreglass ducting is problematic in many respects and potentially dangerous to work with. Galvanised or zinc coated sheet steel is best as it tends to inhibit the growth of mould and mildew.
Once the HVAC ducting has been cleaned it is normal for a post-cleaning ventilation duct inspection to be undertaken. This is done to ensure that the cleaning operation is satisfactory. Again, a video recording can be taken as evidence of the successful procedure.
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