Fire ventilation

Piercing nozzle(fog nail).Alternatives or supplements to fire ventilation, forexample the use of piercing nozzles, should be consideredwhen the fire is strongly ventilation controlled.If the fire gases can be cooled down in this way it will bepossible to implement fire ventilation or internal suppressionwith significantly less risks. Filling with foam can beanother alternative, which however assumes that the requisiteopening can be made. The size of such an opening isoften less than what would be needed for fire ventilation. Itcan often be appropriate to first secure the adjacent roomsor buildings before measures are taken for the fire room. Inthe case of ventilation-controlled fires it can be possible tosave lives in the fire room, since the impact of the heat ontrapped persons can be relatively moderate.Ventilation-controlled fires involve large risks, since thefire gases contains large volumes of uncombusted gases. Inthe event of rapid mixing of large volumes of air there is arisk of backdraft. Above all there is a risk of very rapid flashoverscenarios when fire ventilation is implemented.To take into consideration during ventilation-controlledfires:• Consider alternatives or supplementary methods tofire ventilation, for example cooling of the hotgases with piercing nozzles.• Observe great care during the implementation offire ventilation.• Observe great care during the choice of outlets,both in view of flames that can come out from thefire area and a possible backdraft.• Avoid turbulent mixing of fresh air in the fire gases.• Have a well-planned and coordinated ventilationand suppression operation, since the supply of airwill increase the intensity of the fire and the risk ofspreading the fire and fire gases.112