Performance of “ductless” personalized ventilation in conjunction with displacement ventilation: Impact of disturbances due to walking person(s)

The performance of the novel “ductless” personalized ventilation in conjunction with displacement ventilation (DV) was compared with the performance of DV alone under realistic conditions involving disturbances due to walking of one or two persons. An office room with two workstations was arranged in a full-scale test room. Two thermal manikins were used as sedentary occupants at the workstations. Two pollution sources, namely exhaled air by one of the manikins and passive pollution on the table in front of the same manikin were simulated. The performance of the ventilation systems was evaluated with regard to the quality of inhaled air and thermal comfort of the seated “occupants”. The walking person(s) caused mixing of the clean and cool air near the floor with the polluted and warmer air at higher levels and disturbed the displacement principle which resulted in a decrease of the inhaled air quality. The performance of the “ductless” PV under the tested conditions was better as opposed to DV alone. Thus in practice the “ductless” PV will be superior to DV alone as regards perceived quality of inhaled air. The location of a walking person was found to be important. Person(s) walking close to the displacement diffuser will cause greater disturbance.     

Application of the Field and Laboratory Emission Cell “FLEC” - Performance Study,Intercomparison Study,and Case Study of Damaged Linoleum in an Office#

The Field and Laboratory Emission Cell (FLEC) has been tested and evaluated for qualitative and quantitative emission testing of volatile organic compounds (VOCs) from building products. An air supply control unit has been developed and its performance is reported in the range of 100 to 500 mllmin airflows. The recovery in the FLEC has been tested with a new performance test kit with dodecane and 2-ethylhexanol, respectively. Additionally, five VOCs emitted from a liquid floor wax were measured in the FLEC and in a small climate chamber. The first order rate constants (k₁) and the initial emission rates (R₀) obtained from the time versus concentration data measured over 24 hours proved to be comparable. The application of FLEC in a complaint case of malodorous linoleum in an office building showed that artificial wetting of the linoleum had a marked influence on the qualitative offgassing of odorous VOCs such as fatty acids, glycol ethers, and 2-decenal.     

Interpretation and Limitations of the Concept “Total Volatile Organic Compounds” (TVOC) as an Indicator of Human Responses to Exposures of Volatile Organic Compounds (VOC) in Indoor Air

The TVOC summation of masses of non-reactive substances has often been used as a practical way of reporting environmental measurements of volatile organic compounds. This total concentration, moreover, is often used as an indication of the potential of a multiomponent atmospheric pollution with substances of low chemical reactivity to cause chemically induced sensory irritation. This use of the TVOC indicator has never been standardized. Various authors have used different measuring techniques and the results have been used to predict certain types of health effect. This article discusses the toxicological background for the TVOC concept in relation to nonspecific sensory irritation and identifies some theoretical limitations in its use within this context. The TVOC indicator of nonspecific sensory irritations should be based only on a limited range of compounds and should be interpreted as a lower limit of the possible intensity of sensory irritation. Based on the discussions, some precautions are recommended with respect to measurements of TVOC and interpretation of the measurements.