China's research on PVC plastic flame retardant technology generally has a tendency to one-sidedly pursue the improvement of oxygen index and ignore the research on smoke generation performance. Statistics show that 79% of fires are fatal by smoke. Some UPVC pipes have an oxygen index of more than 50%, but they emit a lot of smoke during combustion, and the Vicat temperature is only between 70°C and 90°C. Therefore, although UPVC pipe is difficult to burn, it is easy to soften and deform, and the smell of smoke is extremely strong. On the one hand, lethal smoke is produced in a fire. The higher the wind speed of the drainage pipe or vent pipe passing through the roof, the faster the fire will spread. Therefore, whether or not UPVC pipes can be used in high-rise buildings has been a matter of debate, and the focus of the debate is its fire-resistant properties.
UPVC pipes have been widely used in high-rise buildings, but the above-mentioned fire protection problems have not been paid enough attention, and no opinions on the installation of UPVC pipes have been put forward during the fire protection special inspection and acceptance. Since the current "Code for Design of Building Fire Protection" GB 50016-2014, "Rigid PVC Pipes for Building Drainage" GB /T5836. 1-92 and "Technical Specifications for Engineering Drainage of Building Drainage Polyvinyl Chloride Pipes" CJJ-96 and other specifications are not Clearly stipulate how to use UPVC pipes, making this problem "out of order". While calling for the promulgation of relevant national documents and regulations, some opinions are put forward for colleagues' reference: (1) Rain, sewage, and ventilation risers should be installed along the outer wall of the building as much as possible. (2) When rain, sewage, and ventilation risers are in the building, they should be installed in the pipeline well, or protected by non-combustible materials such as bricks and concrete blocks. (3) The branch pipes that drain into the drainage standpipe shall be metal drainage pipes, or strict fire protection measures shall be taken for the branch pipes, such as steel casing pipes and inorganic fire casing pipes. (4) Metal products should also be used as much as possible for drainage accessories.
In addition. UPVC drainage pipes still have issues such as standpipe energy dissipation, noise reduction and prevention of condensation, all of which limit the promotion and use of existing UPVC drainage pipes to a certain extent.