When liquids are spilled somewhere, the liquid vapor can have a (negative) effect on human health. Various factors play a role in this evaporation, for example vapor pressure, threshold limit values and dispersion. During a hazard identification, such as a HAZOP study, scenarios are often discussed in which a leak of a certain substance from a process installation is a potential hazard. Sometimes it is quite difficult to determine the dangers of such a leak.
There are various complex software packages that can calculate how much liquid will be released in case of a leak and subsequently determine the concentration of the substance in the air using dispersion calculations.
Consultant Jeroen has written a report in which the (simplified) theory is considered with regard to vapor pressure, dispersion calculations and threshold limit values. A number of sources for chemical properties and threshold limit values are discussed and two simple (free) tools are presented for performing dispersion calculations. Two examples are included in which the theory is applied.