"Classification of building materials and combustion products" disputed

For October 1, 2013 to start the implementation of the " building materials and combustion products classification " (GB 8624-2012), deputy secretary general of China Polyurethane Industry Association, Li Jianbo in every industry forums and seminars he attended a public appeal would , introduction of new standards unfair treatment exists for polyurethane materials industry , and questioned some of its provisions .

All along, the debate about the performance of the insulation wall materials fire did not stop . Public information, " fire performance test methods of building exterior insulation system " mandatory national standard GB8624-2012 " Classification of building materials and combustion products " and recommended national standard GB/T29416-2012 required , low- retardant properties the insulation sheet will be difficult to get the B1 level assessment , the local government only allows the use of not less than B1 grade material is a big trend.

Since then, Gansu Province, Department of Housing and Urban-Rural Development , Gansu Province Public Security Bureau in October 2013 jointly issued the most stringent on the wall insulation combustion performance specifications. Requirements when building height greater than or equal to 50 meters, combustion performance of its external insulation materials should be A-level.

In the Ministry of Public Security Fire Department in 2012 abolished the "further define civil insulation materials fire supervision and management requirements related to notice ", the wall insulation materials for the policy came back to the Ministry of Public Security and the Ministry of Housing in 2009 jointly issued " external wall insulation systems and civil decorative fire Interim Provisions " ( commonly known as" No. 46 " ) era : ." civil combustion performance of external insulation materials appropriate for the a-level , and should not be less than the B2 level , " " but this No. '46 Man ' is a specific clause in question , its provisions with the A -level residential buildings , do not set the buffer zone when the B1 level insulation materials . " Li Jianbo said: " But no isolation B1 grade material with safety you should treat this material be ? ."

EIFS fire test results Li Jianbo of China Academy of Building Research Institute building fire , the Ministry of Public Security Sichuan Fire , Fire Tianjin Public Security Ministry carried out by the three authorities , to prove their doubts and inferences .

The test results show that 10 cm thick , oxygen index of 30 , the combustion level B1 grade EPS (expanded polystyrene board ) system a thin plaster burned in the end , did not pass the test , B1 level XPS ( extruded plate ) as well. Regardless of the level of B1 or B2 level of EPS EPS, rock wool insulation system increases the isolation zone , through a combustion test , XPS as well. In addition , 50 cm thick , oxygen index of 28 , the combustion level B1 grade polyurethane thin plaster system in case of no buffer zone by the combustion test . In addition, 60 cm thick , oxygen index of 26 , the combustion level B2 grade polyurethane thin plaster system in case of no buffer zone has also passed the fire test .

Why burn the same level of different materials , the performance difference between the system model fire so great ? Li Jianbo explain belong thermoset polyurethane foam insulation, a fire burning , charring layer formed on the surface , charring layer can prevent the flames from spreading. The EPS and XPS are thermoplastic materials , when a fire will melt, drip, drip and these are also capable of burning .

"In fact , the material itself is not the problem , the key to use the right, with the good ." Said Li Jianbo , construction site management confusion, failure of non-compliant products on the walls supervision , are the main causes of fire.

China Academy of Building Research Fellow Institute of Architecture fire season which is also widely noted that the combustion performance levels and fire safety EIFS insulation material is not the same concept , fire safety should be emphasized that the overall system structure .Wholesale masking tape


In addition, Li Jianbo think GB " building materials and combustion products classification ", the provisions of the foam insulation on the walls oxygen index , regardless of the specific requirements of the same material used indicators unreasonable. Combustible and oxygen index is inversely proportional relationship between a certain range .

This unit standard editor Sichuan Fire Research Institute of Public Security Zhao Chenggang , director introduction, the standard at the time of submittal of Public Security , B1 grade oxygen index value is greater than or equal to 28 , after the Ministry of Public Security made ​​comments greater than or equal 30 .

" The EU provisions in this regard is 28, and not included in the mandatory targets ." Li Jianbo said . This may lead to the emergence of a strange phenomenon , we recognized the quality of a good number of foreign products , they brought the recipe from direct production abroad , it may be because oxygen can not reach China Index was out of specification requirements B1 grade materials market . The country can produce qualified products similar enterprises and small, may eventually be fake and inferior goods rampage .Masking tape


Although the oxygen index is just one of the indicators , but with "one-vote veto ." Jianbo said , the new standard , as long as the oxygen index of less than 30 , it can not be considered as material class B1 . He believes that , regardless of the specific materials used in the same targets " one size fits all " requirements " unscientific ", " irrational ." " B1 different materials to achieve the same level , the oxygen index is not consistent. To EPS, XPS , for example, after these materials reach the B1 level , the oxygen index can easily exceed 32 , but it is difficult to reach 30 polyurethane , unless you change the production process , but after changing the process , although the oxygen index reached the standard , but other physical and chemical properties , such as heat resistance, robustness will be discounted , but the cost will rise significantly . " he said.

Season it is also widely believed that thermoset materials requiring oxygen index greater than or equal to 30 , the B1 level with some difficulty , although rising costs but also can achieve a lot . The outer wall insulation systems for thermoset materials fire performance requirements are not only recommended thermoset material class B2 as the basic requirements in order to achieve the best value for money .Washi tape


In fact , in the same grade thermoset material with burning thermoplastic materials treated differently, local policies have come in the front . Xinjiang in 2012 on the following requirements, " a residential building height is less than 100 meters , when the thermoplastic material class B1 , the level should be set every three layers Fire Barrier " ; " other civil residential portion of the combustion performance of insulation materials should be Class A or B1 grade thermoset insulation material . "

"The key problem is that the fire is not just caused by insulation material , only emphasizes building materials fire rating itself is not meaningful ." Quarter its wide said.Sellotape