A numerical study of external smoke spread in designated refuge floor

Designated refuge floor is a prescribed requirement stipulated in the Code of Practice on Means of Escape of Hong Kong. Such a floor is considered as a temporary safe place for evacuees under fire or other emergency situations. To prevent smoke logging in the floor, Hong Kongʹs code prescribes that cross-ventilation should be provided. However, whether such requirement is effective has not been analytically studied. In a previous study on the air flow field around and inside a refuge floor, it has been revealed that smoke may spread into the floor by dint of wind action, and whether such smoke will be forced to leave the floor or diluted by the inflow of wind should be further studied. This paper presents a numerical study of wind-smoke field for a refuge floor. It was found that the smoke effect will be dependent upon the location of the fire source, the configuration of the opening at the refuge floor as well as the velocity of wind. This implies that the prescribed requirements may not be appropriate in some fire scenarios.