An Methodology for Quality Control and Draught Assessment of Room Ventilation Supply Using Laser Light Sheets

A common technique to investigate draught problems in a room is to make spot measurements of air velocity. This might identify where the draught problem is located but it does not necessarily identify the distribution and source of the problem. Usually visual inspections of the location of ventilation inlet and smoke experiments are next step to track the draught source. However, these methods do not provide an understanding of the air flow pattern in the room with sufficient resolution to necessarily identify the source of the draught problem. However, laser light sheets together with smoke seeding for on-site visualization of airflow in rooms might be useful for tracking down draught sources in rooms as part of a commissioning process. This paper reports on the first attempts to use this simple method to visualize and characterize air flow patterns in two different classrooms. The visualizations disclosed the air movements, and it was possible to record the movements using a standard smartphone camera. From the movements it was possible to qualitatively assess the overall airflow patterns of the room. The resolution of the video recording was also sufficient to be processed in particle image velocimetry software to gain overall flow pattern visualization, if not accurate readings. The latter result indicates that there could be a potential for real-time velocimetry processing by smartphones but the method in general needs further investigation and documentation.