This research is qualitative research. The purpose of this research is to study the work pattern for setting up operational procedures and developing a method for measuring the petroleum gas levels of a petrochemical company in Thailand. It is research in the field of actual operations with the population with special reference to workers in gas warehouses in all 5 regions in the country. Interview forms were validated by qualified experts and calculation forms were used as tools for data collection.

The research results showed that: the measurement of the gas level started from measuring the depth of the gas water; measuring the temperature of gas water; measuring the temperature of the gas vapor; and measuring the gas pressure and gas molar mass. After that, a calculation was done to find the true volume from the developed calculation model. Table constants in Table 54 were compared to find the Density at 15°C and Table Tank table to find the total gas volume, after which it was then calculated in the developed calculation which made the gas volume increase by 20% more than the previous model.