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(I) Basic Technical Information
The chemical composition and properties of Borosilicate glass 3.3 characterised by their high heat-resistance and chemical stability, is as defined by the international standard DIN ISO 3585. Borosilicate glass represents unmatched standardized glass for construction of plant and piping in the chemical, dyestuff, food pharmaceutical, petrochemical industries. Its steadily growing use is due to many advantages over conventional materials.
• Outstanding corrosion resistance
• Smooth pore free surface.
• Transparency
• Catalytic inertness.
• No effect on taste and odour.
• Physiological inertness.
Products made from Borosilicate 3.3 glass are smooth, non-porous and perfectly transparent, with no catalytic action, and are corrosion-resistant even in demanding operating conditions up to 300°C without sudden changes of temperature.
Borosilicate 3.3 glass, which we use is an environment-friendly product and is completely harmless from an ecological point of view.

Approximate Chemical composition of Borosilicate 3.3 glass
Amount (% by mass)
Na2O + K2O

Chemical Properties of Borosilicate 3.3 Glass
Products made from Borosilicate 3.3 glass are chemically stable, practically inert and characterised by high resistance to the effects of water, water vapour, acids and salt solutions and relatively high resistance to alkalis.

The glass gets etched by hydrofluoric acid and concentrated Phosphoric acid and corroded by hot concentrated aqueous NaOH solution. Constant alteration of acid and alkaline environments increases corrosion.

The chemical resistance of Borosilicate 3.3 glass is specified by the ISO 3585 and is evaluated precisely by the international standard testing methods defined by ISO and DIN ISO.
Chemical resistance of Borosilicate 3.3 glass
Hydrolytic resistance at 98 °C (in accordance with ISO 719)
Hydrolytic Resistance grain class ISO 719-HGB1
Hydrolytic resistance at 121 °C (in accordance with ISO 720)
Hydrolytic Resistance grain class ISO 720-HGA1
Acid Resistance (in accordance with ISO 1776)
Sodium oxide (Na2O) < 100 µg per 1 dm2 of glass when the glass “as a material” is tested (including preliminary acid treatment)
Effects of a boiling aqueous solution of mixed alkalis (in accordance with ISO 695)
Alkali resistance class ISO 695-A2 or better

Physical Properties
The physical properties of Borosilicate 3.3 glass, as shown in the following table, as per ISO 3585standard.
Mean coefficient of linear thermal expansion (ISO 7991) A20/300
3,3 ×10-6 K-1
Density p
2,23 g.cm-3
Thermal conductivity (at 100 °C) w
1,2 W.m-1.K-1
Mean Specific heat capacity at constant pressure cp between 20 and 200 0C
0,8 kJ.Kg-1.K-1

Mechanical strength
The mechanical properties and service life of products made from Borosilicate 3.3 glass are largely determined by the condition of the surface, especially its finish & integrity , i.e. the depth of damage to the surface in handling and secondary heat treatment.
Scratch hardness of glass on Mohs scale
Allowable tensile stress with flame polished surface without any scratch or damage or alteration during service.
10 Mpa
Allowable tensile stress with grounded or flame polished surface where alteration and scratches are possible during service.
7 Mpa
Allowable compressive stress
100 Mpa

The glass system is designed as per EN BS 1595, AD 2000 Merkblatt, PED & ASME Section VIII Division I where ever relevant and the permissible internal working pressure (MAWP) depends on the nominal diameter of the glass components and on working temperature. In case of assembled units comprising of vessels, filters, heat exchangers, etc. the overall permissible internal pressure is limited by the lowest pressure, which one of the components of the assembly can withstand.

Borosilicate glass retains its mechanical strength over a range of temperature and will deform only at temperature, which approach its strain point. The practical upper limit for operating temperature is much lower and is controlled by the temperature differentials in the glass surface, which depends on the external surroundings too. Provided borosilicate glass is not subject to rapid changes in temperature, creating undue thermal shock, it can be operated safety at temperatures up to 250 °C. The high resistance of products made from Borosilicate 3.3 glass to sudden changes of temperature - their heat resistance - is due to a low coefficient of linear thermal expansion, a relatively low modulus of tensile elasticity E and relatively high thermal conductivity. It must be realized that assembled plants are composed not only of borosilicate glass, but also have other materials such as PTFE the recommended max. operating temperature is 200°C. Operating temperatures may have to be modified so as to compensate for the effects of other factors such as pressure, thermal cycling, rapid heating cooling etc.

The degree of thermal shock (usually defined as sudden chilling or heating), which it can withstand depends on many factors such as stresses due to operating conditions, stresses imposed in supporting the equipment, the wall thickness of the glass. It is therefore undesirable to give sudden temperature changes. But up to 120 °C can be accommodated.

At sub-zero temperature, the tensile strength of borosilicate glass tends to increase and equipment can be used with safety at temperatures as low as -50°C.

Our technical cell would be glad to furnish you any other information you might be looking for. Please contact us at consult@bizvalueresources.com for this.

We can supply you total assembled pilot plants designed and engineered as per your requirements. Also all components for plants are available in the major designs prevalent in the international market. You can have a look at the components & equipments, which are available as standard products by following the links given from this page.

(II) Design & Manufacturing Practices
For design, fabrication & testing we strictly adhere to EN BS 1595, AD 2000 Merkblatt & Directives of CE namely PED - 97/23/EC, Machine Directive - 98/37/EC, European Low Voltage Directive - 73/23/EEC, EMC Directive - 89/336/EEC and ASME Section VIII Div. I.

GMP regulations call for special care in both the planning and selection of the components together with the materials of construction used for them, a design without any dead space, which ensures that components drain fully and can be cleaned easily and effectively. We fully comply with such requirements by maintaining the shape of the components, the way they are installed and selection of suitable valves. Where the external surfaces of complete assemblies have to comply with clean room requirements, appropriate stainless steel coupling and support material can be supplied.

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