Convection Velocity Measurements in the Crevices of Furniture

Previous to this study, research has shown that small air veloci ties can strongly influence the ignition propensity of a cigarette on upholstered furniture simulations. However, data were not available to determine if such velocities existed in practice. The two objectives of the current effort were to de termine (1) the typical steady velocities near the cushion of a warm chair due strictly to free convection and (2) the typical unsteady velocities near the crev ice of a warm chair due to a combination of free convection and forced convec tion as a result of a person vacating the chair. Typical steady velocities were 40 mm/s. Typical velocities in the unsteady conditions were 15 mm/s. For the unsteady conditions large velocities remained long after the chair cooled to room temperature due to large vortices in the flow with long time constants.