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.

The study has monitored two office buildings during 3 years changing position of dampers in order to control the air change in the buildings on periods of 3 months. CO2 levels, absenteism rate and rhinovirus in air samples 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 demand for duct cleaning has been increasing exponentially over the last few years and to determine objectively if the duct is dirty and has to be cleaned is necessary.All air-handling units from a school district (18 buildings) and representative portions of their associated ductwork were assessed. Results of dirt and contamination are compared to dirt criterias and commented.

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.

Visual inspection is a subjective method but yet necessary to control duct cleanliness. In order to improve its reliability, a visual scale has been realised and results from a panel of 10 inspectors have been compared to measurements.