This paper deals with the consequences of applying ventilation procedures during underventilated and very underventilated fires in a compartment equipped with a mechanical ventilation network. In this experimental study, we investigate whether the ventilation procedure of enclosure can change the fire development and pose ignition risk in exhaust system. The ventilation procedure consists in closing the inlet vent in order to decrease the quantity of available oxygen. Heptane pool fire experiments are performed in a reducedscale room with and without closing inlet for several Air Change Per Hour (ACPH). Heat release rate depends on ventilation condition in the compartment. The use of ventilation procedures in this case reduces fire duration significantly, and fire can stop due to a lack of oxygen.