Fire safety is always an important issue in the indoor and built environment. There might be hidden conflicts among different systems such as suppression and smoke control. The effect of water spray on smoke movement in halls with natural venting system is reported in this paper. A series of scale modelling experiments were carried out to study the temperature variation under water spray. A small vent on the opposite side of fire source would intensify smoke stratification and result in a higher smoke temperature. Water spray would weaken the smoke stratification due to the cooling effect on the smoke and the downward drag on the smoke layer. The temperature development of smoke was the result of competition of these two effects on the smoke layer. When the effect of water spray was stronger, the average smoke temperature tended to be lower, and the temperature difference of the ceiling to the smoke layer interface was smaller. When the effect of the opening dominated, the results were reversed. These results would be useful for providing fire safety in indoor and built environment.

Lithium-ion battery-powered (LIB-powered) electric bicycles (E-bicycles) are widely used in China, with many accidental fires occurring in parking facilities in high-rise buildings. E-bicycle parking areas in high-rise buildings have become fire-prone zones. There is an urgent need to establish fire codes for the parking facilities in high-rise buildings. However, only limited research has been conducted on protecting against such fires. Uncertainties also remain about appropriate methods for fire barriers and fire suppression in parking facilities. To better understand parking facility fires in high-rise buildings, four fire scenarios and a total of six experiments on LIB-powered E-bicycle fires were studied in this paper, aiming to seek principles on how to prevent serious fire accidents by isolating E-bicycles parked in parking facilities. Fire spread between the LIB-powered E-bicycles and the propagation patterns of smoke generated by E-bicycle fires within parking facilities were studied. The effectiveness of different fire extinguishing methods in suppressing LIB-powered E-bicycles fires was discussed. The reasonable fire separation distance for E-bicycles was determined. It was found that LIBs with ternary lithium-ion batteries (such as nickel-cobalt-manganese) are more prone to initiate thermal runaway. Setting appropriate separation distances could effectively minimize the spreading of E-bicycle fires in high-rise buildings. A sprinkler system with a lower hazard class is proposed to operate under lower water pressure and flow rates. Fire control methods were proposed, including fire-resistive eave and fire barrier. The results can be used in setting up fire code.

Lithium-ion batteries (LIBs) electric bicycles are widely used in China, with many accidental fires occurring in parking facilities in high-rise building. Electric bicycle parking areas in high-rise buildings have become fire-prone zones. There are urgent needs to establish fire codes for the parking facilities in high-rise buildings. But only limited research has been conducted on protecting against such fires. There are also uncertainties in the appropriate methods for implementing fire barriers and fire suppression facilities. To better understand the parking facility fires in this area, four fire scenarios were studied in this paper, aiming to seek principles on how to prevent serious fire accidents by isolating E-bicycles parked in parking facilities. These principles include fire barrier design, fire separation distance between the islands and the selection of fire suppression devices. A total of six experiments on LIBs bicycle fires were conducted. Fire spread between the LIBs bicycles and the propagation patterns of smoke generated by electric bicycle fires within parking facilities were studied. The effectiveness of different fire extinguishing methods in suppressing LIBs bicycle fires was discussed. The reasonable fire separation distance for electric bicycles was determined. It was found that LIBs with ternary lithium-ion batteries (such as NCM) are more prone to initiate thermal runaway. A sprinkler system with lower hazard class is proposed to operate under lower water pressure and flow rates. Fire control methods were proposed, such as including fire-resistive eave and fire barrier. The results can be used in setting up fire code and are useful for AI training cases in developing fire models.