Behavior Of Glass Breakage In Enclosure Fires

Glass, for its unique advantages of transmission, is widely used in various modern architectures. However, glass often becomes a weak link in the fire protection design of buildings. Window glass breaking plays an important role in compartment fire dynamics as the window acts as a wall before breaking and as a vent after breaking.The criterion of temperature difference for glass breakage suggested in previous work can only used in those cases with large shading and fast heating. However, it can't fit some requirements for the glass components during the design of fire protection in most other cases. In this work, a new criterion for glass breakage is developed, namely, the heat flux criterion, which can be widely used in most cases. In addition, the method of performance-based fire design is also proposed for glass components.Based on the ISO9705 full scale experimental setup, the glass breakage behavior in an enclosure fire environment is analyzed. With the float glass of 4mm and 6mm thick as the experimental targets, the work measures the following parameters under the conditions of different fire sources: enclosure gas temperature, local gas temperature, exposed glass surface temperature, shaded glass surface temperature, glass surface heat flux, the glass breakage time and breaking patterns. The relations of glass breakage and parameters like the glass surface temperature distribution are analyzed. The relations between the first breakage time with respectively gas temperature, heat release rate and heat flux are also studied. The results show that vents can be more easily formed for larger and thicker glass. In the case of toughened glass, their fire resistance show distinguished difference among themselves. In addition, the thicker, the better fire resistance.In terms of the type and installation of glass, the heat flux is used as the criterion of glass breakage for edge-protected and edge-exposed glass to guide the design of fire protection. This new criterion can be used for various glass components. What's more,...