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At least 253 records · Page 14Linked to original sources
PubMed1986

Investigations concerning the standardisation of control-investigations of supply-air in air-conditioning systems in hospitals.

In the following investigation, air-germ measurements were conducted--using the Reuter-Centrifugal-Sampler (RCS) and the Sartorius-Sampler MD 3 (SAR), and using standardized nutrient-substratum and breeding conditions--in order to detect differences in the measuring process itself. The aim of the study was to find a standard for routine-measurements in hospitals. A special "Supply-Air-Box" was developed because of the known turbulences during the emission of air from the channel; in order to cut off the interference-factor during the measurements caused by the blending with the room-air. The results of the air-germ measurements showed a sufficient reproducability and a good representation of the results in differing measuring positions with both devices during repeated measurements. A marked difference between the two measuring-devices are the markedly higher CFU-numbers in the measurements using the RCS-device and the resulting higher variability of the single-values. The measurements using the supply-air-box show that--with the usual measuring position immediately in front of the supply-air grille screen or without grille screen at the channel end--a considerable part of room-air is also registered during the determination of the CFU-number because of the existing turbulences. Because of the markedly lower CFU-numbers with this procedure, new recommendations were suggested for the maximal mean CFU-number in the supply-air. Accordingly, not more than 5 CFU/m3 of air should be found with three-step-filtered supply-air in well-maintained installations for the inrestricted utilization of the rooms, and not more than a mean value of 30 CFU/m3 of air with two-step-filtered supply-air.

Air Conditioning↗
PubMed1989

Changes in lung function after working with the shotcrete lining method under compressed air conditions.

Shotcrete techniques under compressed air are increasingly applied in the construction of tunnels. Up to now little is known about the influence of shotcrete dusts on the function of the lung. The lung function of 30 miners working with shotcrete under compressed air (before and after one shift) was measured. They carried personal air samplers to assess the total dust exposure. Long term effects were studied on a second group of 29 individuals exposed to shotcrete dusts and compressed air for two years. A significant increase of airway resistance and a significant decrease of some flow-volume parameters were found after one workshift. These changes partially correlate close to the dust exposure. After two years exposure a significant decrease of mean expiratory flow (MEF)50 and MEF25 was found. These results point to damage in the small airways and emphasise the major role of the lung function test--including the flow-volume manoeuvre for the medical examination of the workers. Additionally, they should carry filter masks.

Adult↗
PubMed2006

Development of air conditioning technologies to reduce CO2 emissions in the commercial sector.

BACKGROUND: Architectural methods that take into account global environmental conservation generally concentrate on mitigating the heat load of buildings. Here, we evaluate the reduction of carbon dioxide (CO2) emissions that can be achieved by improving heating, ventilating, and air conditioning (HVAC) technologies. RESULTS: The Climate Change Research Hall (CCRH) of the National Institute for Environmental Studies (NIES) is used as a case study. CCRH was built in line with the "Green Government Buildings" program of the Government Buildings Department at the Ministry of Land, Infrastructure and Transport in Japan. We have assessed the technology used in this building, and found that there is a possibility to reduce energy consumption in the HVAC system by 30%. CONCLUSION: Saving energy reduces CO2 emissions in the commercial sector, although emission factors depend on the country or region. Consequently, energy savings potential may serve as a criterion in selecting HVAC technologies with respect to emission reduction targets.

Journal Article↗
PubMed1975

Airborne infection in a fully air-conditioned hospital. II. Transport of gaseous and airborne particulate material along ventilated passageways.

A mathematical model is described for the transport of gaseous or airborne particulate material between rooms along ventilated passageways. Experimental observations in three hospitals lead to a value of about 0.06 m.2/sec. for the effective diffusion constant in air without any systematic directional flow. The 'constant' appears to increase if there is any directional flow along the passage, reaching about 0.12 m. 2/sec. at a flow velocity of 0.04 m./sec. Together with previously published methods the present formulae make it possible to calculate the expected average amounts of gaseous or particulate material that will be transported from room to room in ventilated buildings in which the ventilation and exchange airflows can be calculated. The actual amounts transported in occupied buildings, however, vary greatly from time to time.

Air Conditioning↗