ATEX - Dilution 1

[safetystudies]

Hello,
I would like to calculate the air flow to dilute an explosive gaz volume. Here is my exemple :
LIE 3,3%
Volume of ethanol (Gaz volume)= 50 m3
Building volume : 2000 m3

The volume of ethanol is released in one hour. It's saturated of ethanol vapor.

Could you please help me to calcule the flow of air to never reach an explosive condition?
Thank you very much.

 

[quark]

What is ATEX and what is LIE?

Ethanol has an LEL (lower explosive limit) of 3.3%. Presuming 100% ethanol vapor, your air refresh rate should be (50*100-50*3.3)/3.3 = 1465 cu.mtr/hr. This flow rate keeps the concentration exactly at 3.3%. Any flowrate above this (take a target percentage and replace it in place of 3.3 in the above equation) will keep the building ambience from being cooked.

Caution: Don't fold your sleeves yet. TEL for ethanol is 1000 ppm (or 0.1%), which should be your target. Secondly, I would seek ways to contain ethanol vapor (for ex. localised exhaust with suitable filters) rather than spreading it around.