Just how quickly will haze dissipate in a closed room? The dimensions are I believe 61ft wide, 40ft deep, and about 20ft high. Theres no real way for ventilation, as we only have air ducts for air conditioning, and they only pump air in. We have doors, but if we have a performance those will remain closed (but unlocked during all business hours ). We're pumping enough haze to see the beams for a specific scene, but I'm not sure how long it will last after the scene. Any idea how long the audience will be seeing light beams?