The Lifa Ventilation hygiene concept for circular and rectangular air supply and exhaust ducts and HVAC air handling and air-conditioning units. Same cleaning and investigation equipment is also used for industrial vent and pipe lines. The concept consists of: criteria for cleaning and cleaning results methods for the visual evaluation of cleanness plans for cleaning optimal choice of the cleaning method advanced cleaning equipment and procedures quality assurance systems and education material

Dirty supply air duct in a hospital Air duct after cleaning

DuctControl Mini Remote controlled video/digital camera system using a built-in mini tractor by which it is possible to survey cleaning needs and record the quality of cleaning afterwards. It is also used to reach the visual inspection to the critical parts of ductwork where access doors can’t be made.	DuctControl Manual Light and small hand controlled version for vertical and very small ducts where the use of robot is not viable.
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Special Cleaner 20 Electrically driven cleaning machine with a wide range of accessories. Ideal for small ducts.	Hydmaster Powerful remote controlled hydraulically driven cleaning machine with optional integration of video camera to the brush unit for real time control of cleaning quality. Hydmaster has a wide range of accessories, e.g. Y-gear for rotating 2 brushes in rectangular ducts.	HepaClean 4000 A low-pressure vacuuming unit that is adaptable to the maintenance opening or air valve site of the ventilation duct. The other valves are then covered. First the branches of the duct are cleaned using a rotary brush. Powerful airflow (10–20 ms/s) is needed to carry the loosened dirt into the collecting filter bag of the low pressure vacuum unit. Then the filtered exhaust air is conducted outside the building. A High Efficiency Particulate Air (HEPA) filter is used when there is not a possibility to conduct the air out of the facility.
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The ventilation system in general

Inspections of the cleanliness of ventilation ducts have normally been done by taking samples and making sensory inspections via the inspection hatches and at the incoming or outgoing air valves. The ducts have not normally been inspected throughout their whole length, and post-cleaning quality assurance inspections have normally been done from the inspection hatches only.

Lifa Air Ltd has done, and continues to do, much innovative development work to ensure that cleanliness inspections of the ventilation system are done thoroughly and well. Lifa Air Ltd has developed remote-controlled video camera robots and systems by which it is possible to survey cleaning needs, and check the quality of cleaning afterwards.

40 % of the contaminants in indoor air come with the incoming air via the ventilation system. The distances between filters in these incoming air ducts are often too long, and impure air may flow past them. Regardless of the filters in the ventilation system, some particulate contaminants from the outdoor air will enter the system and accumulate on the inner surfaces of the ventilation equipment or flow with the incoming air into the ventilated spaces themselves. And that's not all. Contaminants may accumulate during the manufacture, transport, storage and installation of the ventilation equipment, and thus lower the quality of the incoming air. The contaminants originating from equipment manufacture include oil residues in the ducts. Equipment which is transported and stored in unprotected form may collect contaminants from the outdoor air and the ground. During installation, particulate contaminants such as cement dust and metal powder may also accumulate.

The dirt that collects in ventilation equipment and on duct walls and in various heat recovery, refrigerating, humidifying and air distribution equipment may act in humid conditions as a fertile soil for microbes.

The different kinds of indoor air problems derive mainly from a lack of regulations and maintenance, and partly from poor planning. Almost anything can be found in ventilation ducts that have not been cleaned - ranging from building waste to bird carcasses and excrement. Air inlets polluted by organic waste may become colonies of microbiological compounds which spread with the ventilation system throughout the whole building.

Ventilation system contaminants
Examples of various contaminants which are found in ventilation ducts or equipment and in cooling systems.

The particulate contaminants accumulated on the surfaces of ventilation systems, their sources and period of accumulation.

Contaminant
Organic dust Bacteria Fungi Pollen Algae Plant parts & insects Protozoa Viruses	Inorganic dust Inorganic dust from ground Coal dust Flue dust Soot Heavy metals Cement dust Metal dust Oil Inorganic fibres Lubricants & grease
Contaminant Source
Organic nature Industrial processes Birds Cooling towers Water systems Air humidifiers Damp, wet materials Excrement of arachnids	Industrial traffic The raw materials of sheet metal Sound and heat insulation made of mineral fibre Motors, gears and lubricants of fans
When accumulated
Use of ventilation system. Storage, transport and installation of ventilation equipment.	Use of ventilation system. Installation of ventilation system.

Is our present knowledge enough to identify all the effects of ventilation system contaminants on people's living environment and health? For example, if bird droppings get into the ventilation system, they may contain Histoplasma and Cryptococcus fungi or other excrement-based fungi and bacteria. What is the risk to a hospital, if these fungi, when inhaled, lead to infections in patients with immunity deficiencies?

Regulations on cleaning ventilation ducts

Until now, ventilation systems have been cleaned voluntarily in Finland. The regulations affecting ventilation systems have been drawn up to cater for fire safety, and thus they seldom relate to incoming air ducts. On the other hand, the dust and grease that accumulate in the exhaust air ducts of buildings have been regarded as a fire risk, and their cleaning is therefore officially regulated.

According to the regulations of Finland's Ministry of Internal Affairs, ventilation equipment must be cleaned at least once per year for the sake of fire safety in the following types of premises:

• premises for professional food preparation
• industrial premises in which air ducts accumulate much flammable material
• premises where flammable liquids are used or made