Vapor density is the weight of a volume of pure gas or vapor compared to that of an equal volume of air at the same temperature and pressure. A vapor density of less than 1 indicates that the gas or vapor is lighter than air and will tend to rise. A vapor density of greater than 1 indicates that the vapor is heavier than air and will tend to accumulate closer to the ground. It may also move a significant distance at these low levels to a source of ignition and then flash back to the original location once ignited. When using vapor density to determine optimum sensor placement, other factors such as air flow patterns and temperature gradients should also be considered.

Now you’re in the know. If you have any questions regarding sensor placement, read our blog post, Best Practices for Gas Sensor Placement and Installation.