BOR Calculation

The boil-off rate (BOR) for LNG (Liquefied Natural Gas) tanks refers to the rate at which LNG vaporizes or "boils off" from the stored liquid phase to gas.

Calculating the boil-off rate is essential for designing LNG storage tanks. The BOR is influenced by factors such as tank design, insulation, ambient temperature, and storage duration.

Here's a simplified overview of how to calculate the boil-off rate for LNG tanks:

Basic Formula:




  • BOR is the boil-off rate (in tons per day or other relevant units).
  • Q is the boil-off rate factor, representing the heat leak into the tank (in kW).
  • H1​ is the enthalpy of the LNG at storage temperature (in kJ/kg).
  • H2​ is the enthalpy of the LNG at the boiling point (in kJ/kg).



The actual boil-off rate can vary based on factors like tank efficiency, insulation quality, and ambient conditions.

Always consult the specific guidelines, standards, and data provided by the LNG tank manufacturer or industry regulations for accurate and site-specific calculations.

Online BOR Calculator

We have an online calculator that does the job for you. Have a look at it here: