Introduction

Asbestos fibers, the common name of the silicate mineral fibers, were found in nature and exploited in the long term. Many studies have showed that these fibers may directly affect human health. In over the world, there are more than 40 countries which have banned the use of asbestos fibers. The prohibition of Asbestos fibers is becoming a global trend and many other countries are considering or have taken the route of banning from the exploitation and the use of asbestos.

In 2001, Vietnam government introduced regulations banning Asbestos fiber in all forms and recommended residents to use non asbestos products. In 2004, due to the actual situation, the government allowed to extend the using period of time for white asbestos fibers. Besides, the government banned the construction of new asbestos plants and encouraged the study of alternative fibers in stead of asbestos fibers. And from that, government encouraged to produce and use non asbestos products.

One of fibers which are used to produce non asbestos roofing sheet now are PVA fiber. Because of the prominent features of Vietnamese PVA in producing non asbestos roofing sheet such as high tensile strength, elastic modules, especially the strong links with molecules in the process of cement hydration, stretchable, alkaline resistance…Therefore, up to now the PVA is the best alternative for asbestos fiber.

The production of PVA fiber roofing sheets has one great advantage based on Hatcheck technology that most of plants are still in use. They just replace the PVA fibers from Asbestos fiber and change the combinations of materials. This allows plants that are using old technologies have the opportunity to access and move to new technology with lower costs.

Technological line which produces non-asbestos roofing sheets (replaced by PVA) was installed in Vietnam in 2007. Since 2008, the PVA non-asbestos roofing sheets has been widely available on domestic and international markets with very high quality.