Explores the complexities of guidance for the ventilation of hygiene systems. The UK Health & Safety Executive estimates that 30 to 50% of refurbished buildings cause some form of sick building syndrome. It is obviously important that building managers take the necessary steps to establish programmes to maintain ductwork systems in a safe, effective and hygienic state. The UK Heating & Ventilation Contractors' Association and Building Services Research & Information Association have produced documents providing guidance on the hygienic maintenance and cleaning of ductwork.
For many years there has been an increasing rate of complaints on the air quality in nonindustrial buildings. The occupants suffer from many diseases especially problems of breathing. Besides other reasons the air-conditioning systems themselves pollute the indoor air because dust, aerosols and other substances deposit inside the system. Therefore an airconditioning system, which has been operating 26 years was investigated. The aim was to find the main pollution sources of the system and possibilities to eliminate them.
A nine-home field study was conducted to investigate the impact of mechanical air duct cleaning (ADC) methods on indoor air quality (IAQ) and system performance. ADC services were provided by the National Air Duct Cleaners Association (NADCA). Only mechanical ADC methods were evaluated. Surface treatments, such as biocides or encapsulants, were not part of the study. Pre- and post-ADC measurements were used to evaluate impacts.
In this study, the effect of duct cleaning on the indoor air quality and on the ventilation system hygiene in non-problem office buildings: was investigated. Six office buildings were selected from local duct cleaning companies' contracts. A questionary was distributed among the occupants prior to and after the duct cleaning. Also several air quality parameters were measured in outdoor air, indoor air,· and supply air and ventilation system hygiene measurements were performed prior to and after duct cleaning.
The aim of this experiment was to study the effect of air duct cleaning on the indoor air quality. Three buildings in the Helsinki metropolitan area were selected for the study. In two of the test buildings the ducts were cleaned using three different cleaning methods. The third building serves as a control where no cleaning was done. The air handling systems in the test buildings had operated 26 and 30 years without cleaning.
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.