English

The study presents a cost analysis including energy calculations for three outdoor climates (cold, moderate and hot) to improve indoor air quality in an existing building considering both variable air volume (VAV) and constant air volume (CAV) systems with heat recovery. The study also simulates different indoor air quality levels due to different airflows of outdoor air.

The study investigates the relationship between ventilation rates and work performance on two specific tasks (talk and wrap-up) in a call-center. CO2 concentrations ranged from 13 to 611 ppm and the study used a multi-variable regression to modelize the association between the predictors and the responses. Influence of ventilation rates and temperature on task performance are commented.

This new standard goes much further than previous one in addressing pre-cleaning assessments, control and containment during the cleaning process as well as a lot of other variables that can impact the indoor environment. This paper looks and comments the new standard and how it addresses the many variables that influence duct cleaning and IAQ and how the document deals with the many different building populations.

The paper presents hygiene requirements to be met by hospital HVAC plants and analyses them critically for different type of rooms (confined rooms sterile protected, operating room, special areas). The tasks of comfort air conditioning are adapted to the improved indoor conditions of intelligent buildings. Air is only used for ventilating, whereas heated and cooled room surfaces generally serve for heating and cooling.

In the context of the definition of new national ventilation cleanliness classes in Finland, it is important to develop a clean method for the installation of ducts. An important factor that makes the inner duct surfaces dirty is the metal dust that is accumulated while side grinder is used to cut the ducts.

The aim of this study was to evaluate the amount of dust in supply air ducts in 18 recently installed ventilation systems constructed according to two different class of cleanliness. Dust accumulation into the duct can be partly avoided by duct protection during the whole of the construction phase.

The effect of duct cleaning has been checked on 15 buildings. Indoor air quality measurements and questionnaires have been operated 3 months before cleaning and 1 month after. Questionnaires show that the perceived indoor air quality has been improved. Effects of cleaning on measurements can hardly be measured.

Maintenance is often limited to repair and failure response and not dedicated to indoor environment. The study defines levels of cleanliness depending on the method of measurement and compares surface values on the components to air pollution in order to decide if guidelines with limit values for surfaces are sufficient.

Labelling of HVAC systems is a direct consequence of the publication of test procedures and recommended criteria in Finland. Cleanliness parameters are dust quantity, oil residues and odours emissions. Discussion isf continuing on filters classification including their efficiency (EN 779) but also odour emissions.

Ways of removing from indoor air particulates smaller in diameter than 1 micrometer, through enhancement of particle deposition in a filter, were investigated using numerical simulation. Deposition enhancement is obtained using diamond-shaped three-dimensional roughness elements incorporated into filters. Numerical investigations performed were used to define the enhancement for laminar flow, in order to define the most efficient arrangement of enhancing elements.