How is vapor density defined?

Vapor density is defined as the density of a gas (or vapor) compared to air. This measurement is important in understanding how a gas will behave in the atmosphere, particularly in terms of its buoyancy or tendency to rise or fall. When vapor density is less than that of air, the vapor will rise, whereas if it is greater, the vapor tends to settle. This concept is crucial in fire protection and safety, as it informs responders about how gases emitted from materials may disperse in the environment, especially during fire scenarios or hazardous material incidents. Understanding vapor density aids in assessing hazards and helping in the response strategies by predicting the movement and accumulation of gases in confined spaces or open areas.