Resources » Informer » MET 6.5 for Windows

The most important new features in MET® Version 6.5 are:

This new feature allows for the estimation of release rate and danger distances for tanks with compressed gas.

Either a release from a hole in the tank wall (A) or a hole in a supply line (B) can be assessed.

This extension is of interest for accident assessments or for the assessment of the influence of e.g. the hole size on the release speed.


For the assessment of the release from a liquid spill, the vapour pressure of the substance is an important factor. This is usually known only for a certain temperature, e.g. 20°C. If a liquid flows onto a hot surface, such as a tarred street in the summer, or the liquid itself is warmer or colder, the consequence is a deviation.

Example: If the calculation is done with the vapour pressure of methanol at 20°C, but the temperature of the liquid is 37°C, the release rate is underestimated by a factor of 2.3. If the temperature is 3°C,  the release rate is overestimated by the a factor of 2.7.

In order to reduce this deviation, the vapour pressure in relation to the temperature was entered into the database of MET for Windows as a vapour pressure function, or the function was estimated with the critical pressure and critical temperature. Because these data are known only for a few substances, a broadening of the model now allows for the assessment of the critical pressure and the critical temperature of the chemical structure and of the measured boiling point with the help of the method of Wilson and Jasperson. Because for many substances the boiling point and the structure are known, this method significantly increases the accuracy of the release from a spill puddle.

Due to the appearance of the new revisions 28 and 29 of the PAC toxicity values, changes in the toxicity values have been observed for more than 1000 substances.

To the right of the graph you see the plot of the new PAC-2 values against the previous ones. The changes are, in part, striking. For example, benzenesulfonyl chloride had a PAC-2 value of 200 mg/m3. With the new revision the substance has a PAC-2 value of 8.4 mg/m3. The substance is now considered 23x more toxic.



Over 80000 safety data sheets (MSDS) from Sigma-Aldrich 2016 were added, in German as well as in English.

The Openstreetmap-Map on the USB flash stick has been updated.




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