gasoline

[Jasmine2000]

There is a gasoline tank and I am trying to calculate the LEL % AND UEL% BASED ON VAPOR PRESSURE. ANY IDEA HOW TO DO THIS? THE TEMPERATURE IS 100F AND PRESSURE IS 14.7 PSIA

 

[Compositepro]

LEL and UEL are measured values and are not related to vapor pressure, directly.

 

[JLSeagull]

Are you interested in the upper and lower explosive limits inside the tank or nearby? Blanket the tank with nitrogen.

 

[ash9144]

Check the MSDS.

 

[cheute79]

As stated by Compositpro, LEL and UEL are measured values. You can find them, as stated by ash144, in the MSDS or in handbooks, or even on the internet (do a Google search). However, I suspect that you are using the wrong terms, and are looking to find what the vapor concentration is above the gasoline in your tank, and if you are in the explosive range within the tank.

You cannot calculate based solely on vapor pressure. There are factors that are involved such as mixing and diffusion, location of fill/vent line, and other factors. I can guarantee you that you are over the UEL near the liquid/vapor interface, and possibly to the fill nozzle. If you remove the cap, you will be below the LEL somewhere around the cap.

The issue is, why do you need to know? If you need to weld on the tank, the best thing to do is fill it with water. Filling it with gasoline and purging like crazy with an inert gas near the weld is next best. Empty and purge for days (with inert gas) is next best.