Since natural gas is colourless, odourless and flavourless, due to safety reasons it is odorized for public use, so that the occasional natural gas escape can already be smelt before it reaches the concentration of an inflammable mixture. The odorizing substance is generally added to the natural gas on the national gas transmission system, so already the odorized natural gas arrives at the traders and service providers.
Natural gas is not poisoning, is easier than air (its density is approximately 0.68 kg/m3 while that of the air is 1.293 kg/m3).
The quantity of natural gas is measured in the normal state cubic metre in Hungary (1m3 equals to the quantity of gas the volume of which is 1m3 at a pressure of 1.01325 bar and at 15 °C), but the settlement with the consumers is based on the energy content, in MJ. The energy content is the product of the calorific value depending on the gas content (MJ/m3) and the quantity (m3).
It is important to distinguish natural gas from the liquid crude oil gas (TNG or propane-butane gas), which is a product of crude oil processing, and can be stored in containers and bottles. The liquid crude oil basis gas (butane gas) is heavier than the air.
In the course of the perfect natural gas combustion it burns with a blue flame, without harmful combustion products, soot, ash, with an insignificant carbon monoxide and sulphur dioxide emission – that is why it is one of the clearest energy sources from an environment protection aspect.
Natural gas forms an explosive mixture if it mixes with air in a proportion between 5 and 15%!