The specific gravity of a gas simply means its weight compared to the same volume of air. It is measured using a numerical scale, with air serving as the benchmark and assigned a value of 1.
Any gas with a specific gravity higher than 1 will fall towards the Earth’s surface, whilst any gas with a specific gravity lower than 1 will rise in the atmosphere. But why is this important?
Well, if you know the specific gravities of particular gases, you will understand where they might accumulate in confined spaces. Gases can be heavier or lighter than air, so you need to ensure that environmental monitors are placed in the correct position within the confined space to detect the gas.
Additionally, you’ll have a better estimation of how the presence of specific gases may affect safe working in a confined space.