Cleaning technology of the HVAC systems.

The aim of the experiment was to study the efficiency of three duct cleaning methods. The methods used were ( 1) rotating brushes, (2) compressed air cleaning, and (3) wiping by hand. The air handling systems under investigations had been in use 26 and 30 years after the construction phase and the systems had not been cleaned since buildings were completed. Accumulated amount of dust in the supply air duct was determined by BM-Dustdetector, tape method, and by visual inspection before and after cleaning. The amount of dust on the duct surface was decreased with all three cleaning methods.

The impact of HVAC system cleaning on levels of surface dust and viable fungi in ductwork.

Samples of surface dust were collected from ducts before and after an HV AC system cleaning project in an office complex in Canada. Dust levels were quantified gravimetrically and concentrations of viable fungi were determined (1) using a standard dilution plating method from vacuum-collected surface dust samples; and (2) by the collection of surface samples on commercially available agar contact slides.

Measuring methods for determining the level of dust in the air duct.

The aim of this experiment was to compare three measuring methods to determine the level of dust in air ducts. Compared methods were a vacuum test, a tape method and an optical method. The dust samples were taken from the supply air ducts of new buildings. The paper presents and compares the results of the tests. The samples were taken from three day-care centers in the Helsinki area. The ducts were not cleaned after the manufacturing process or protected during the construction. Duct surfaces had also oil residues from the manufacturing process.

Identifying and removing pollutants from heat recovery ventilators.

This study investigated the presence of allergens such as dust and molds in heat recovery ventilation systems and the duct work. It also looks at two different types of cleaning equipment and their ability to clean these pollutants from the rigid and flexible ductwork and heat recovery ventilator (HRV) cores in dedicated balanced supply and exhaust ventilation systems. Samples from the ductwork and cores of ten ventilation systems were tested for levels of dust and mold.

Playing the field.

A US company is using electric fields to remove airborne contaminants. Ewen Rose reports

Dust load on surfaces in animal building: an experimental measuring method.

To investigate the physical process of particle deposition on and resuspension from surfaces in animal buildings, a test facility and a sampling method is established. The influences of surface orientation and air turbulence and velocity just as other parameters on the dust load on a surface are analysed. It is found that the surface orientation is the parameter which influences the dust load most. The dust load is highest on the floor but some dust is also sampled on the walls and the ceiling.

The effect of loading dust type on the filtration efficiency of electrostatically-charged filters.

Ventilation filters composed of electrostatically-charged fibers, also referred to as electret filters,are know to have the potential to decrease in filtration efficiency with use. However, little datahave been available on whether such decreases are seen in actual applications.

Low temperature heating systems: impact on IAQ, thermal comfort and energy consumption.

The Netherlands Agency for Energy and the Environment(NOVEM) is conducting a program for the implementation of Low Temperature Heating (LTH) systems in buildings. The primary goal is to enable the use of Low Talued Energy as a heating source. Major savings in enery consumption can be realised by fully utilising the potential of Low Valued Enery. Besides the argument of savings in energy supply, there are additiond benefits in the fields of. Indoor Air Quality (particles, mites, lower air temperature, annoyance and dust);.

Dusty, dry air and sick building syndrome.

This investigation was carried out on a mechanically ventilated office building with a high prevalence of occupant symptoms. The commonest complaints were of dry air, stuffy air and noise. Occupant symptoms, however, were most strongly associated with reports of dusty air and static electricity. Allergic and asthmatic people suffered the most. Cleaning standards were high, and upgrading the air filters failed to give improvements in occupant symptoms. Air flows to the rooms were adequate, but air movements in the rooms were poor.