Archive for the ‘Dispersion’ Category

High Pressure Gas Cylinders…Relief Valve Failure

Friday, September 17th, 2010

The following video desribes 2005 fire/explosion in Praxair's gas cylinder filling and distribution center. The incident occurred when gas from a pressurized propylene cylinder was released through the relif valve and got ignited. httpv://www.youtube.com/watch?v=-_ZLQkn7X-k This is one of those situation where the risk mitigation measure (i.e. relief valve) is creating a hazard.  In situations where there is demand on the relief valve, ...

Posted in Dispersion, Fires and explosions, Incident Investigation | No Comments »

SO2 vs. H2S: Which is more toxic?

Friday, June 25th, 2010

I noticed that API-14C recommends monitoring of 2-ppm (and higher) SO2 levels. I felt this was a really low threshold value for SO2 . What surprised me further is that the Immediately Dangerous to Life or Health (IDLH) value for SO2 is 100-ppm...same as H2S! Intuitively, I did not think SO2 was as toxic ...

Posted in Consequence Modeling, Dispersion, Toxicity | 3 Comments »