Yes, fresh air must be able to pass under the fire table to safeguard against residual gas accumulation. Failure to allow proper ventilation may cause a fire or explosion. If installing this fire table without the optional legs, it should be placed on a hard-level surface that allows proper ventilation through the ½” gap incorporated into the bottom. If the installation method blocks the incorporated gap, an alternative method for allowing ventilation would be required. Required minimum clearances (to combustible materials): Sides and back - 48 inches (122 cm). Top - 72 inches (183 cm).