In a fire-compartment, the “ventilation parameter” AH½ is related to the fresh air intake and hot smoke exhaust from the door. Below the neutral plane, the air is drawn into the structural and then above the plane the exhaust gases from combustion are removed. The identification of the plane is made once the opening is done. This identification aids in the indication of the location of the fire. When the fire is detected in a particular area in the compartment, the opening of the door at the front is done that will allow the hot smoke to exhaust out from the fire-compartment at the top part whereas the fresh air will be allowed to come in from the lower part of the fire-compartment. This process is where the opening is the vent and is created with regards to the fire in the fire-compartment.However, if the height of the opening is done under the neutral plane then the hot smoke flows out from the new vent might not be seen, hence the heat amount that flows is higher but the heat loss is smaller in the lateral surface thus the thermal discontinuity plane is determined. In this case, the temperature of the fire-compartment will become higher and flashover may occur. Therefore, the hot smoke layer high and compartment temperature are related to the size of the “ventilation parameter” AH½ of a fire-compartment due to the mass flow of the fresh air intake and hot smoke exhaust will be affected.