An Exploration On The Mechanism Of Structural Measures Of Fire Building Exterior Insulation System

Entering the new century, as the energy crisis is increasingly serious, the world has to raise all energy-saving to unprecedented levels. The building field is a major social energy consumer, so the implementation of building energy efficiency is imperative. However,2009 Beijing CCTV fire and 2010 Shanghai 11.15 fire deeply reveal that China is facing severe fire safety problems in heat preservation areas while the building energy efficiency is being forcefully promoted.Compared with interior insulation systems and sandwich insulation systems, exterior insulation system has the following advantages:elimination of "thermal bridge effect", better energy saving effect, effective protection of exterior wall structure, wider areas of appliance, etc. which has been widely applied in domestic and international architectural thermal insulation as an important link of building energy efficiency in our country. But domestic research on external thermal insulation system focus on application more than theory, especially on fire safety performance whose study is almost blank, and domestically there is no specification or standard to solve this problem. The severe casualties and economic loss caused by the frequent happening of building exterior insulation fire in recent years set off the long-term alerts to China's fire prevention safety of external insulation.To solve the fire safety problem of external thermal insulation system, I analyzed the developing course of building energy efficiency at home and abroad, summarized the current situation of external insulation fireproof technology, and put forward the reasonable structural measure is the main way to improve the fire prevention safety performance of exterior insulation system in which the flammable organic heat preservation material is extensively utilized at present. My study is based on a project named "Research on the Fire Test Method of Exterior Wall Thermal Insulation System, Evaluation Standards for Fireproof Rank And Application of Technology in Building Scope" operated by Beijing Zhenli Energy Conservation and Environmental Protection Technology Co., LTD. and Building Fire Research Station in China Construction Science Research Institute.The third and the fourth chapter comparatively analyzed the fire state in the test condition and the damage status of the two systems after test, that is, polystyrene plastered system which is widely popular in Chinese external thermal insulation market and polyphony board system which adopts no-cavity, storehouse patch structure and the protective layer measures, respectively through large size window fire model test which is closely relevant to real external insulation fire and corner fire model test.The fifth chapter concluded different temperature variation curve of insulation layer in insulation heat preservation system in the window fire test and corner fire test by data processing, and the temperature field distribution law in the corner fire test. It revealed the response performance of two insulation system to test fire. Combining the combustion state of insulation system and heat preservation material in the experimental process with the analysis on anatomical wall structure after test, my study proved the positive effect of protective layer structure, storehouse structure and structure without cavity in terms of fire safety performance in exterior insulation system. Protective layer structure can protect thermal insulation through effectively relieving the radiation effect on the internal heat insulation layer from the outside world; No cavity structure and storehouse structure can effectively limits the convection and conduction in partial combustion system, and control fire in the local area to avoid its spreading.