Commercial buildings are usually located in the city downtown district, of where has a dense crowd, a large variety of commodity, many combustible materials, and poor natural ventilation exhaust fume conditions.

The raw material and products of petroleum and petrochemicals industry are mainly flammable and explosive, and the complicated production technology and various production equipment easily give rise to explosion and fire accident.

As the develop of power network, the automation of electric system is constantly improving, in order to ensure the safety supplying of power energy, the hierarchy of needs for fire fight system is higher and higher.

Communication room, data center is developing with the informationize and the popularity of information system, and the workplace is usually colorless, odorless, non-electrical conductive, and equipped with electrified objects and precise instruments.

Airport terminal and bus station as the important traffic hinge buildings, there functional diversification, mutual intelligibility space, huge passenger throughput, high personal density, put high requirement on continuous operation.

Because the overall engineering of tunnel and metro is set underground, normally it has only in-and-out two operating planes. So with the restriction of tunnel space, after fire, the flame and smoke cannot diffuse upward but to diffuse longitudinally.

And there are many chemical medicines in hospital, during the using process of high-power medical equipment whose using frequency is high, it would be extremely adverse both for the security of patients and medical workers if there is potential risk in hospital.

Port and pier is the important traffic hub which connects inland river, sea, railway and highway, is the main place of container handing and container yard. Because of the rich varieties and giant quantity of the stored and transferred commodities, the in-time control for the commodities in container is impossible.