Arbetsberedningar Utvärdering och åtgärder för ökad spridning av yrkeserfarenheter
This bachelor thesis has the purpose to visualize and document the air movementsprovided by different ventilation principles in an operating theatre. The visualizationwill be made as simple as possible in a physical model. The model and thedocumentation should be able to use in educational purposes.The study is based on the two most common systems for airflow, currently used inoperating theatres. The first principle is displacement ventilation in which the air issupplied at low velocity along the floor. The second principle is vertical parallel laminarairflow in which the air is compressed like a piston from ceiling to the floor.A review of literature resulted in the choice of size, design, and scale factor for themodel, as well as choices of ventilation principles and airflows. When the model wascompletely built and ready to use the air movement were made visible with smoke. Thevisualization of the air movements was documented with videos.The series of experiments with vertical parallel airflow give a result of air movements,which looks reasonably the same for the different tested velocities of the supply air. Theair is forced down over the operating table, and forming a sterile zone, obtaining theform of a cylinder around and over the table. Between the outer edge of the sterile zoneand the walls the smoke accumulates in air eddies.The experiments with displacement ventilation provides a visualization of the airmovements that spreads from the diffusers in the corners to the operating table via thefloor, and then rise in a more turbulent pattern of movement towards the exhaustdiffuser in the ceiling.The visualization of the two air supply principles in the model leads to the followingconclusions:The model is suitable to visualize the air movement arising from the principle ofvertical parallel airflow. The visualization of air movements with displacementventilation will be more realistic if the experiments were made with lowered velocity ofthe supply air, if the supply air is colder than the air in the operating theatre and if heatsources are placed in the room.The model can be easily understood and used to visualize air movements in anoperating theatre. The model can be used to give hospital staff a better idea of theimportance of the ventilation in operation theatres.Eddies in the air movements are a problem in all experiments. Less eddies are detectedat higher air velocities and with partial exhaust at roof height. To sort out what impacteddies have on protection ventilation requires more studies focusing on this factor.A continued development of the model will make the visualizations of the airmovements in the model more realistic.