Technical Information

Physical Properties

Borosilicate Glass 3.3 is versatile both in universal resistence to corrosion due to corrosive chemicals and has very low thermal expansion coefficient.Hence, no need for expensive measures for controlling thermal expansions due to variation in temperature. The major physical properties are

Properties Values
Mean thermal conductivity 1.2W/mK
Density r = (2.23 + 0.02) g/cm2
Mean specific Heat Capacity Cp = 0.98KJ/Kg-K
Modulus of Elasticity E = 64KN/mm2

Chemical Properties

Component % by weight
SiO2 80.6
B2O3 12.5
Na2O 4.2
Al2O3 2.2
Remaining 0.5


Borosilicate Glass 3.3 is reistant to almost every existing chemicals excluding HF Hydrofluoric acid H3PO4 Phosphoric acid and strong Caustic solutions. Concentrated form of Hydrofluroic acid effects largely on glass while normal Phosphoric acid and Caustic solutions has no or less effect.

Mechanical Properties

The compressive strength is high in Borosilicate Glass 3.3, while the tensile strength is low due to which it can easily withstand pressure & the glass process plant are supported from the lowest point.

Properties Values
Permissible tensile & bending stress 6 N/mm2
Permissible comprehensive stress 100 N mm-2
Poisson’s ratio 0.2

Optical Properties

Due to its versatile properties Borosilicate Glass 3.3 shows no absorption or adsorption due to which it remains clear & colorless & hence a better see through medium is obtained. Thus accordingly process like chlorination , sulphonation & other miscellaneous process can be carried out easily as there no interference of light in the process from glass.

Permissive Pressure

As in all kind of material of construction used in chemical process plants, the permissive pressure for Borosilicate Glass 3.3 depends upon,
- Internal diameter of glass
- Working temperature

In whole process plant there are different kind of glass and non glass components hence there working pressure is always calculated by there running in vacuum conditions.

Permissive Temperature

All Borosilicate Glass 3.3 components can be operated safely till the temperature range of (0-200) oC provided that there is no shock both thermally and physically. Morever the working of equipments also depends upon the non glass fittings like PTFE components.

Thermal Shock

Sudden change in temperature or pressure leads to a shock condition for glass, i.e tremendous strain is generated in glass which has a adverse effect on the operating pressure of glass equipment. To overcome such effect, a value 120K of maximum permissive thermal shock is set for general glass equipments.

Glass Buttress End

All the glass equipments shown in our catalogue have standard Flat Buttress End as, which can be changed accordingly. The major dimensions of Buttress End are mentioned in table below.

Nominal bore
DN mm
Buttress end diameter
D mm
25 42.5 (+) 0.0, (-) 1.5
40 57.5 (+) 0.0, (-) 1.5
50 70 (+) 0.0, (-) 1.5
80 99.5 (+) 0.0, (-) 1.5
100 133 (+) 0.0, (-) 2.0
150 185 (+) 0.0, (-) 2.0
200 232 (+) 0.0, (-) 2.0
225 259 (+) 0.0, (-) 2.0
300 340 (+) 0.0, (-) 3.0
400 464 (+) 0.0, (-) 4.0
450 525 (+) 0.0, (-) 4.0
600 684 (+) 0.0, (-) 6.0


Repairing of any damaged glass equipment is possible. Generally the cost involved is less compared to original cost but sometimes in case of certain damages it becomes uneconomical. Below mentioned are some points which clarify the cost of repairing.

  • Greater skill is required to execute repairing
  • Sometimes the damage is up to such extent that while repairing total damage can take place, which leads to loss of time & effort.
  • Throughout attention is required for accomplishment.
    Moreover repairing job involves receiving, cleaning, handling, estimating its cost etc. Which increase the repairing cost.
    Further for sending an equipment for repairing following precautions should be taken.
  • Before sending the material for repairing mention the nature of damage & take estimation of repairing to avoid transportation cost if repairing is not economical.
  • Always go for a substitute of damaged equipments as repairing takes longer time to fit in the production schedule.
  • Clean up the equipment before sending for repairing, as cleaning at owner’s premisies is much viable and economical.
  • Good care should be taken of packing the damaged equipment, since cracks in glass increase with every little jerk.
  • Generally repairing job is undertaken for the equipment manufactured by us that too at complete owner’s risk.