Vapour Pressure of Diesel Fuel - QS Study
QS Study

Vapour pressures of diesels at room temperature are very low; that discussed in has a vapour pressure of 0.4 mm Hg (E 0.053 kPa). That for cetane is less than 1 mm mercury, yet another ‘plus’ for cetane.

The calculation concerning the vapour pressure of a diesel in below:


We first note that a p.p.m. in the hundreds is certainly likely to exceed the odour threshold and this is consistent with common experience in the handling of diesel. No odour threshold appears to have been established for cetane. We can cautiously compare diesel with n-dodecane in these terms as this has a vapour pressure of 0.3 mm Hg, a value typical of a diesel. Its odour threshold is 5 p.p.m.

The value of 530 p.p.m. can be broadly compared with threshold limit values for pure hydrocarbon compounds. The threshold limit value (TLV) for styrene is 20 p.p.m. That for cyclohexane is 300 p.p.m. That for toluene is 50 to 100 p.p.m. Other examples can be given but enough has been said to support the view that the diesel concentration in the calculation is sufficient to be harmful.