The special properties – especially its high chemical resistance, its resistance to temperature and its low coefficient of linear expansion – of the borosilicate glass 3.3 exclusively used by QVF for the construction of glass plant and pipeline are achieved by strict adherence to its chemical composition, which is as silica(SiO2)- 81%, boric oxide(B2O3)- 13%, alkali(Na2O)- 4%, and others- 2%

Borosilicate glass 3.3 is resistant to chemical attack by almost all products, which makes its resistance much more comprehensive than that of other well-known materials. It is highly resistant to water, saline solutions, organic substances, halogens such as chlorine and bromine and also many acids. There are only a few chemicals which can cause noticeable corrosion of the glass surface namely hydrofluoric acid, concentrated phosphoric acid and strong caustic solutions at elevated temperatures. However, at ambient temperatures caustic solutions up to 30% concentration can be handled by borosilicate glass without difficulty.

Borosilicate glass 3.3 can be classified in accordance with the relevant test methods as follows:

• Hydrolytic resistance at 98 ºC- Hydrolytic resistance grain class ISO 719-HGB 1
• Hydrolytic resistance at 121 ºC- Hydrolytic resistance grain class ISO 720-HGA 1
• Acid resistance- Deposit of Na2O < 100 mg/dm² to ISO 1776
• Alkali resistance- Alkali resistance class ISO 695-A2