Smoke ventilation from the opening of an isolated machine room inside a clean room

The manuscript provides numerical simulation results and experimental data of the ventilation of an isolated room inside a smoke control zone in a clean room. The objective of the present study is to determine the controlling factors that affect the air flow directions, and to specify the proper size and location of the opening that can actually ventilate the smoke out of the isolated enclosure for a clean room. An isolated enclosure of reduced scale was built and tested to simulate the actual situation. A simulation model was developed and verified by comparing the velocity distribution with the measured values. Then, the verified model was applied on various opening sizes, locations and the numbers of fan filter units (FFU) for the full scale clean room. Both reduced scale and full scale simulations show that the smoke can flow out of the isolated room only if the pressure inside the isolated enclosure is greater than that outside the room. The FFU coverage ratio and the raised grating coverage ratio are the controlling parameters that affect the pressure distribution and the air flow direction at the vent of the enclosure. There factors should be considered to provide effective ventilation.