1. Incident Date:1/11/2012 Time:07:30 AM Fatality: 25 injuries: 131 Total losses: <200 MM SR Reading in Riyadh Liquefied Gas Explosion This Presentation contains unsuitable Pictures

2. 2 Introduction In last 2 days we have gathered information about Riyadh biggest fire incident in history to correct some information which misguided professional in what happened at that morning. We have analyzed a lot of reports and Pictures to come out to a conclusion of what happened. The truck contains more than 17 tons of liquefied propane at 150 PSI pressure. In fire Since what happened is a vapor cloud at which called { UVCE} UVCE Stands for “ Unconfined vapor cloud explosion.

3. 3 Location were the liquefied gas truck hit the causeway Post when trying to make a left turn at high Speed Wind Directions

4. 4 ALZAHED Contractors Building

5. 5 Vapor Cloud Dimensions

6. 6 Source of ignition from AlZahed Contractors building, and as we See the Amount of Damage is High in this Zoon Another avoidance of source of ignition is the high number of fatalities and injuries from AlZahed Employees.

7. What Happens to a Vapor Cloud? Cloud will spread from too rich, through flammable range to too lean. Edges start to burn through deflagration (steady state combustion). A vapor cloud is defined as flammable and/or toxic materials heated above their boiling point and released to the atmosphere Vapor clouds may be visible or invisible on the material released to the ambient temperature, wind velocity, and humidity. Cloud will disperse through natural convection. Vapor cloud may ignite and flash, resulting in an explosion and flash fire. Anyone caught in the vapor cloud will likely be seriously injured or killed. Substantial material damage is also possible Vapor clouds may be toxic, flammable, or dependent both. Materials with boiling point below 21 C are assumed to vaporize 100% Flame velocity will increase with containment and turbulence. If velocity is high enough cloud will detonate.

8. Chemical Reactions EXPLOSION = Rapid Equilibration of High Pressure Gas via Shock Wave Physical ExplosionsChemical Explosions Propagating Reactions Uniform Reactions Thermal Explosions Deflagrations (Normal Transport) Detonations (Shock Wave)

9. Potential Energy Coursed by the explosion PRESSURE, psig TNT EQUIV., lbs. per ft 3 10 100 150 1000 10000 0.001 0.02 0.03 1.42 6.53 TNT equivalent = 5 x 10 5 calories/lb m Stored Volumes of Ideal Gas at 20° C

10. Impact of VCEs on People 70 160 290 470 670 NA 1 2 5 10 15 20 30 35 150 Peak Overpressure psi Equivalent Wind Velocity mph Knock personnel down Rupture eardrums Damage lungs Threshold fatalities 100% fatalities Effects

11. The area effected by 17 tons of LPG 1 2 5 10 17 20 50 100 200 500 1000 INVENTORY (tons) 120 150 200 250 294 310 420 530 670 900 1150 UVCE Distance in Meters

12. Some views from the incident