Research on Flashover Prediction Method of Large-Space Timber Structures in a Fire

Due to the flammability of materials and the vastness of space, flashover fires of large-space timber structures pose a huge threat to lives as well as the structures themselves. Therefore, it is necessary to study the critical conditions, control factors and prediction methods of flashover fires. To address this issue, hundreds of design conditions were simulated by Fire Dynamics Simulator (FDS) with variations in space size, the heat release rate (HRR) of fire source and fire growth type. A temperature–time model of the maximum temperature of the smoke layer near the ceiling (Tmax) was established, and the critical condition that uses this model to predict the occurrence of flashover was determined. Furthermore, a mathematical formula was established that can accurately predict the flashover induction time when the Tmax exceeds 400 °C. This research can provide a reference for the performance-based fire safety design of large-space timber structures.

Fire Performance of Automated Tall Car Park Structures

Automated tall car park structures are modern alternatives to conventional parking structures to save space and volume in highly demanded parking regions in urban areas. -The design of such structures has significant knowledge gaps especially in regarding the effects of fire spread between passenger cars. The purpose of this study is to estimate the horizontal and vertical fire spread between passenger cars in automated tall car park structures and provide fire safety design to eliminate fire spread and possible structural collapse. The fire spread between cars is established by estimating irradiance heat flux of each car component. An 8-floor automated tall car park structure is designed in accordance with European standards. The results show that steel car pallets underneath cars reach to 1000 degree Celsius in early phases of fire, which could potentially cause a structural failure. Without any fire protection on the structure, the fire spreads to the neighboring cars in 25 minutes and to the cars above in 20 minutes. Significant fire protection is needed to eliminate fire spread between passenger cars. A more effective sprinkler system is also proposed to suppress the car fire.

Effects of Time to Unactuate Air Conditioning on Fire Growth

Air conditioning systems have become essential equipment in many buildings. However, fire safety design and management in buildings rarely consider whether to turn the system off or keep it on in a fire. This study ignites a stack of wood in a room center or corner to explore the influence of air inlet actions of a fan coil unit (FCU) with the door opened or closed. Simulation results using Fire Dynamics Simulator (FDS) demonstrate that the heat release rate (HRR) and room temperature obviously decrease when the room doorway is closed, regardless of whether the air conditioner is turned on. The air supply for combustion is poor. When the door of the room is opened, turning off the air conditioner can effectively reduce the HRR and the room temperature in the early stages of fire growth. However, along with the fire growth, turning on air conditioning can help decrease the heat radiation feedback and the consequent HRR. Therefore, the conclusion that air conditioning always enhances a fire because it provides oxygen may not always be correct.

Customising Evacuation Instructions for High-Rise Residential Occupants to Expedite Fire Egress: Results from Agent-Based Simulation

As the possibility of safe escape is one of the most crucial aspects of a building’s fire safety features, understanding of human behaviour under fire conditions is important for a successful evacuation. Although most of today’s buildings are equipped with fire safety systems, a fire can still occur at anytime and anywhere in a building and have devastating consequences. In the last decade, researchers and practitioners have used information technology to assist with fire safety design and emergency management. Building Information Modelling (BIM) is an exemplar process whose underpinning digital technology has been helpful for fire safety design, simulation, and analysis, but there is a lack of research on how BIM-based models combined with agent-based simulations can help improve evacuation via effective navigation and wayfinding in high-rise residential buildings. Customising evacuation instructions based on BIM, simulation results and occupant location, and delivery of these bespoke instructions to occupants’ smartphones during a fire emergency is relatively novel and research is needed to realise the potential of this approach. Therefore, this study investigates how customised evacuation instructions delivered to each occupant in a high-rise residential building could result in a faster evacuation during a fire incident. The research adopted a case study building and used Pathfinder (agent-based evacuation simulation software) to simulate evacuation from this eleven-floor high-rise residential building in Cairo, Egypt. Constraining evacuees (simulated agents in Pathfinder) to take particular exit routes was used as a proxy for delivering customised evacuation instructions to actual evacuees. Simulation results show that, in general, allowing the use of lifts for the benefit of disabled occupants could lead to their misuse by able-bodied occupants; evacuees would attempt to use the first visible point of exit regardless of how crowded it is. With optimally customised instructions, the evacuation time was, on average, 17.6 min (almost 50%) shorter than when the occupant’s choice of egress route was simulated based on standard path planning factors such as route length, nearby crowds and visible hazards. With evacuation instructions sent via smartphones, occupants could exit more rapidly via alternative routes. Such bespoke instructions were shown to reduce the adverse effects of crowdedness and uneven distribution of occupants along vertical and horizontal evacuation routes on evacuation time.

Preliminary Study of Fire Damage on Pervious Concrete with Silica Fume and Steel Fiber

Pervious concrete pavement is a porous urban surface. It could reduce runoff capacity, decrease a storm-water detention, reduce the amount of requiring rain drainage pipes, and let rainwater filter into ground and allow groundwater resources to renew in time. Fire damage, could be one of important factors since European countries have been used pervious concrete in buildings construction. This study was conducted to assess the fire damage on pervious concrete with silica fume and steel fiber. The test results find that pervious concrete with 10% silica fume and 2% steel fibers showed the maximum increase in compressive and flexural strengths by 60% and 23% respectively over the control mix while maintaining adequate permeability. It also shows that the flexural strength of pervious concrete with 10% silica fume and 2% steel fiber could reach 45 kg/cm2 strength specification. The high temperature exposure results find that pervious concrete could hardly be detected any crack at the temperature of 700 °Cor 800°C and fire duration of 2 hours. There is some damage on strength after the fire-attack test, the ratio of the residual strength can range from about 20%~60% and it depends on temperature, steel fiber, and silica fume content. By this study of pervious concrete will be valuable for fire safety design and construction of practice.