Niemelä R., Kemppilä S., Korhonen P., Nykyri E., Reijula K., Seppänen O.
Bibliographic info:
25th AIVC Conference "Ventilation and retrofitting", Prague, Czech Republic, 15-17 September 2004

The aim of this paper is to investigate the effect of improved air distribution on symptoms and self-evaluated productivity in a landscape office in which the air was distributed with ventilated cooled beams. The intervention consisted of the improvement of evenness of the air distribution by installing an extra whirl diffuser at the end of every second cooled beam. As a consequence, the draught risk quantified by the draught rating model DR, was reduced to some extend. During the pre-intervention conditions 34 % of the respondents experienced draught whereas after the intervention the corresponding value was 17%. The indoor questionnaire also showed that the prevalence of dry throat, stuffy nose and fatigue reduced by 4 to 8 percent-units. The self-estimated productivity increased, because 17% of the employees during the pre-intervention conditions were working below the average efficiency whereas only 12 % after the intervention. This paper shows that a relatively small decrease in air velocities may result in reduction of symptoms and increase in the self-estimated productivity.