Technical Features of LPG

What is LPG?

Colloquially known as “cylinder gas”, LPG (liquefied petroleum gas) is a source of energy used for cooking, heating and lightning. LPG is a colorless and odorless gas. However, a special odor has been intentionally added so that a potential leak can be detected easily. LPG is produced by refining crude oil in refineries or from natural gas and delivered to the consumers in steel tanks. LPG, which is heavier than air due to its high density, is a hydrocarbon-based combustible gas. LPG is the generic name of the butane and propane gases and their mixtures in different proportions. In Turkey, LPG used in household gas cylinders consists of 70% butane and 30% propane.


Cylinder Gas is present in both liquid and gas forms. When the device connected to the bottled gas starts to be used, the gaseous LPG at the top is depleted. The liquid LPG at the bottom evaporates to replace the depleted gas using the thermal energy it draws from its surroundings. Because LPG is a liquefied gas under pressure and has a boiling point of approximately 0°C, it is in gaseous state at room temperature. LPG is superior to other fuels because it can easily be liquefied under pressure, stored and transported conveniently in steel cylinders, and can vaporize easily even at low temperatures.

Is LPG toxic?

LPG is a non-toxic gas. Neither LPG, nor the propane and butane it contains, has any toxic effects on the human body if inhaled. There is a common fallacy that LPG is toxic. Deaths occurring due to a LPG leakage happen not because LPG is toxic but because it reduces the amount of oxygen in the air since it is heavier than air.

Does LPG freeze?

It is not possible for LPG to freeze under normal living conditions due to its chemical properties. Liquid LPG turns into gas even at 0°C due to ambient heat energy transfer. In cases where the ambient temperature in the place where the cylinder is located falls below 0°C, it becomes harder for LPG to boil because it cannot possibly transfer enough energy, and as the cylinder tries to transfer heat energy from the cylinder wall, the water vapor in the air first forms dew, and then freezes. This phenomenon, colloquially known as “freezing cylinder”, is in fact water freezing on the the cylinder walls. In this case, the cylinder cannot produce an adequate amount of gas, and the devices powered by gas will not operate. Therefore, the correct location of use for cylinder gas is a well-ventilated environment at room temperature.

Can a cylinder gas explode?

To supply the flow required by the attached device, the LPG in the cylinder boils with the energy it takes from its surroundings and turns into gas. The pressure of the cylinder gas varies between 2 and 3 bars depending on the ambient temperature; however, the operating pressure of the cylinders is designed to be 17.5 bars. If the pressure inside the cylinder exceeds 26.5 bars, the safety valve on the cylinder opens and the high-pressure gas is released, preventing the pressure in the gas cylinder from increasing further and the bottled gas from exploding. After they are manufactured, the cylinders undergo a resistance test. For bottled gas to explode, the pressure inside the cylinder has to increase to very high levels (50 bars and above), the cylinder has to remain in fire for a certain period of time, or the safety valve has to fail to open. What is in fact meant in most of the news stories about “bottled gas explosions” in the media is the explosion of gas that is released into the environment and comes into contact with a fire source, rather than an explosion of the gas cylinder. For these reasons, caution should be exercised to make sure that cylinders used in homes have passed resistance and leakage tests and that their safety valves are functional.

Is LPG dangerous?

LPG cylinders and LPG-powered devices which are manufactured in compliance with the standards are designed with strict safety standards and are equipped with safety components. In this regard, LPG is as safe as other energy sources that you can use in your home.