![]() Results in the PPVL mock-up and real hospital ICU room showed that the rooms were fundamentally well mixed and showed rapid recovery from perturbations and simulated fan failure. The investigations provided evidence to validate the PPVL isolation facility. Aerosolised bacteria was released from the “mouth” of the DIN man-patient. Sample locations are marked with crosses in Figure 2. Six tubes were located at 1.45 m (breathing height) around the bed, and an extra tube was connected to the extract. Two DIN men were used to simulate the heat loads from a nurse and patient. Most of the tests were done with the door closed, but the room was also challenged by leaving the door open, repetitively opening and closing of doors and simulations of fan failure.įor both gas tracer and bacteriological experiments, the sampling points were located around the bed at the same distances from the source (0.5, 1.0 and 2.0 m). In the gas tracer tests (denoted as GTT) a known flow rate of gas was released from different points in the room (bed, sink, lobby, corridor) and the concentrations were measured around and outside the room when steady estate had been reached. Nitrous oxide (N 2O) and Carbon Dioxide (CO 2) tracer gases were used to simulate airborne infection and to quantify and characterise the patterns of air movement produced within the isolation room. This data was then used to plot 3D plots of the temperatures and speed within the isolation room and as input data for computational fluid dynamics (CFD) modelling, especially when investigating the pressure stabiliser. ![]() A vertical array of anemometers was used on a grid of points on the floor. Room air movement surveys provided air speed and temperature data in the isolation room, to investigate thermal comfort issues. Flow visualisation using smoke from a generator and smoke pencil was an important diagnostic technique to characterise air flow patterns. People simulators or DIN-Men (See Figure 3) were used to simulate the heat load from staff and patient. Studies were carried out through full-scale experiments in a PPVLmock-up room, a real hospital ICU isolation room and a bioaerosol facility at the University of Leeds. Anemometry, smoke, particle and gas tracer tests were used to investigate air mixing and the implications pressure differentials have in the effectiveness of an isolation room.įurther tests carried out at the University of Leeds studied the influence of room layout (see Figure 2) and the risk of exposure when staff were very close to the patient and also compared the behaviour of tracer gas to an aerosolised bacteria (Bacillus subtilis). BSRIA studied the ventilation and protection levels for staff within and outside an isolation room.
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