The storage buildings have generally a very high fire load. This leads to impressive fires, which make however few victims. It is difficult to extinguish these fires after the flash over. Not withstanding the designed fire resistance of the structure, structural failure may be expected at some stage of the event. To guarantee the safety of the firemen, the precise type of failure is essential. Collapse must occur in a ductile mode in the compartment under fire. This collapse should not trigger a further collapse of next elements of the structure that are submitted to lower temperatures. Design of firewalls must take into account the interaction of the wall with the structure, that will deflect. Properly designed standard steel structures perform well under fire and make it possible to meet these safety requirements, that have been included in the new French regulation on fire safety of storage buildings (August 2002).