Indoor air quality assessment in office buildings

Summary

The assessment of indoor air quality in an office building is given. The analysis of the results of reviewing Russian and foreign authors on this topic showed that at CO₂ concentration of 600–800 ppm and higher the well-being of people worsens, which leads to impaired productivity and increased fatigue. Prolonged exposure to carbon dioxide in humans can lead to chronic diseases. The results of an experimental study of the change in carbon dioxide concentration in an office of a public building with an area of 30 m² with continuing presence of five people are presented. The CO₂ concentration was measured using MT 8057 portable carbon dioxide detector during 24 hours. According to the measurement results a graph of CO2 concentration is plotted against the time. It was concluded that the air quality was not satisfactory during certain periods of the working day (from 10:40 to 13:30 and from 14:45 to 19:00 the CO₂ concentration exceeded 1000 ppm) which indicates problems with the ventilation system and excessive sealing of the room (because of plastic windows). The necessity of taking measures to improve the efficiency of inflow exhaust ventilation has been substantiated.

Key words

carbon dioxide , ventilation , personalized air terminal device , air quality , air exchange , public buildings , sick building syndrome,

Personalized forced ventilation system in an office building

Summary

Improving the air quality in the working area of the office space is an urgent task. The design feature of such rooms is a small height (about 3 m) that complicates supplying the required volume of induced air without creating drafts in the working area. It is noted that the solution to this issue is associated with the use of new materials and technologies in practice. These include textile ducts made of 100% polyester with carbonic fiber weave. This material possesses strength, wear-resistance, minimal ablation of particles from the surface. Unlike steel zinc-coated air-ducts, it is possible to cut with laser precision holes with fused edges of the required pitch and diameter in the textile ducts. A lay-out of arranging personalized forced ventilation in an office building based on a designed air terminal device with a microperforated textile insert is presented. This device provides for adjusting the air flow depending on the individual needs of the person up to shutting down the system in the absence of an employee. Reducing induced air flow contributes to the energy efficiency of the ventilation system.

Key words

displacement ventilation , personalized air terminal device , microperforated textile insert , forced ventilation system , office , polymer composite materials and technologies , текстильный воздуховод , microjects , microholes

Personalized air terminal device

Summary

The issues of developing the methods of designing air exchange in civil building premises are considered. These methods are related to the introduction of innovative air terminal devices in practical design of ventilation systems. The analysis of the efficiency of air exchange arrangement in the premises of civil buildings with the use of traditional ventilation systems was carried out. The conclusion was drawn about the necessity of designing an innovative air terminal that provided for spot cooling of the workplaces with rapidly damping micro jets. The basic configuration is presented of the designed personalized air terminal device based on a textile insert with microholes (0.2–0.6 mm diameter) that will allow supplying inlet air by low-pulse micro jets into the human breathing zone. The advantage of the designed device is in the possibility of supplying the required air amount into the human breathing zone. This will provide for the regulatory and comfortable parameters of the microclimate. The introduction of the personalized air terminal device allows improving the efficiency and cost effectiveness of the ventilation system.

Key words

ventilation systems , air distribution , displacement ventilation , personalized air terminal device , microperforated textile insert