میترا رشیدی

The clean room is under the control of concentrations of airborne particles play an important role in the production of drugs and high-tech products. Clean air flow pattern in the room is one of the important parameters of particle concentration and distribution of air pollution and need to be accurately modeled. So in this study was to evaluate and simulate the flow pattern of clean air in the room was investigated.
This study used an experimental study that was conducted at 2015 in the pharmaceutical industry .The methodology used in this study was to determine the air flow pattern in cleanroom. In this study, 3 clean room with 3 cleanliness classes B, C and D were studied. Then simulate the flow pattern, determine the velocity vectors in the cleanroom is cleared by CFD techniques.
The findings of this study showed that air flow rate measured in experimental models with air flow rates predicted by FLUENT software under the same conditions and at the same spacing is very close to each other .Also airflow velocity contours for 3 the cleanliness class were determined .In addition, the results of measurement of particle concentration in clean rooms shows the mean concentration of particulate contamination in three classes cleanliness was below the standard limit.
This study showed that RNG K-ℇ turbulence model the most appropriate model to simulate air flow pattern in the room is clean. There is also equipment and a tool in a clean room on the pattern of air flow and ultimately affects the particle removal efficiency in the clean room.

Survay of the particulates, biological molecules and other harmful materials which enter into Earth's atmosphere as airborn agents is one of research intrest of health sciences. Animal housing laboratories for producing malodor especially near residential, educational and official areas can cause neighbors complainant. In order to overcome this challenge qualitative and quantitative evaluation of airborn contaminants of Iran university of medical scienses animal housing had been done.
In order to sampling and evaluation of the airborne contaminants in the animal housing the ASTM D3686-95 (for VOCs), ASTM D 4490-90 (for NH3, CO2 and, H2S) and, NIOSH 0500 (for total dusts) standard methods had been used. According to the survey goals apparatus and equipment were prepared and calibrated.
According to the results, the unspesified mixed dusts need controling measures and, also showed the presence of the toxic substances like xylene and ethyl benzene, 1, 2, 3-trimethyl Benzene. However the analyses of these show trace concentration of mixture exposure in the air. High number of animals in the small areas and large animal such as rabbits are responsible for more ammonia production.
More frequently passing through the salons and geographical condition of the building and also natural ventilation of the laboratory all are good methods reducing the concentration of pollutions. In the other hand long times presence of employees in the laboratory could cause reduce sensitively. Nevertheless in order to increase employees and researcher welfare the implementation of general ventilation is recommended

The welder's health threat due to exposure to welding fume is an important issue, so effective exhaust of fumes are needful for to be assured from the workers safety in exposured to such proccess. In this study, was evaluated prototype operation of local exhaust ventilation on-gun in bench scale.
duct velocity Average was determined by using traverse points method and calculated flow rate by hood using ACGIH standard method. Also capture velocity close in contaminant source (Arc Point) was measured using thermal anemometer. Then in order to determine total particles concentration and capture efficiency created by system, Was used NIOSH 7200 standard method.
the results show that, duct velocity average and created flow rate by evaluated system was obtained respectively 6296.1±92.50 fpm and 34.06±0/50 scfm. Also capture velocity in close the weld point was obtained 140 fpm. Sampling results shows averaged total particles concentration in off and on positions of system, respectively 75±7 mg/m3 and 16.7±4 mg/m3. As a result achieved containment efficiency 77% by this system.
The local exhaust ventilation used in this study was a low cust prototype and according to acheived results, it lead to reduce total particles concentration (T.P) in breathing zone aproximately to 22%.