Dow Fire and Explosion Index (FEI) Dick Hawrelak Presented to ES317Y in 2001 at UWO

Introduction V1.0 was first Issued in 1964 By Bill Braise (RIP). V7.0 was last issued in 1994 and is now marketed by the AIChE ($50/copy). n FEI is widely used outside of Dow. n FEI is the leading hazard index methodology recognized by the chemical industry. n V7.0 is available on my CD in Folder (9) as Dow FEI V1.3.

What is the Dow FEI? n The Dow FEI is a ranking system that gives a relative index to the risk of individual process units due to potential fires and explosions.

What is the Primary Purpose of the Dow FEI? n It serves as a guide for the selection of fire and explosion protection methods. n It assists in determining the spacing between adjacent process units within the ISBL. n It is a guide for insurance agencies to set insurance rates. n It ranks individual process units where special safety attention can be focused.

When should one perform an FEI? n Late in Phase III Engineering after: u P&IDs have been completed, u Equipment has been sized, u A trial equipment layout has been done, u A DFC estimate has been completed.

Who Usually Performs the FEI? n Generally a senior process engineer, who is acquainted with the details of the project, is assigned the task. n Occasionally, different groups tackle the assignment and results are compared for consensus building.

What Does the FEI Consider? n Six general process hazards. n Twelve special process hazards. n Nine process control credit factors. n Four material isolation credit factors. n Nine fire protection credit factors.

General Process Hazards n Exothermic reactions. n Endothermic processes. n Material handling and transfer n Enclosed or indoor process units. n Access. n Drainage and spill control.

Special Process Hazards n Toxic materials. n Sub-atmospheric pressure (<500 mmHg). n Operating in or near flammable range. u Tank farm storage flammable liquids. u Process upset or purge failure. u Always in flammable range. n Dust explosion. n Pressure.

Special Hazards Cont’d n Low temperature. n Quantity of flammable/unstable material. u Liquids or gases in process. u Liquids or gases in storage. u Combustible solids in storage. n Corrosion and erosion.

Special Hazards Cont’d n Leakage – joints and packing. n Use of fired equipment. n Hot oil heat exchanger system. n Rotating equipment.

Process Control Credit Factors n Emergency power. n Cooling. n Explosion control. n Emergency shutdown. n Computer control.

Process Control Factors Cont’d n Inert gas. n Operating instruction procedures. n Reactive chemical review. n Process hazard analysis.

Material isolation Credit Factors n Remote control valves. n Dump or blow down control. n Drainage. n Interlocks.

Fire Protection Credit Factors n Leak detection. n Structural steel. n Fire water supply. n Special systems. n Sprinkler systems. n Water curtains. n Foam. n Hand extinguishers. n Cable protection.

FEI Example

General Process Hazards

Special Process Hazards

Fig 8: Damage Factor

Process Control Credit Factors

Material Isolation Factors

Fire Protection Credit Factors

Credit Factor Summary n Process Control, C1 =0.75 n Material isolation, C2 = 0.88 n Fire Protection, C3 = 0.79 n C1xC2xC3 = (0.75)(0.88)(0.79) = 0.52

Process Unit Risk Analysis Summary

Plot Plan Summary

Features Not Used In V7.0

Limitations of Dow FEI n No scientific basis for many of the features can be found in Dow records. Fig 8 is an example. (RAH study – 1993). n Does not correlate well with known plant disasters (Flixborough, Phillips, Norco). n While explosion damage is fairly advanced (Flixborough – 1974), fire damage alone is more difficult to predict. n Not scenario driven as in recent QRA work in Holland and the U.K.

Recent Trends n Insurance companies are looking at Maximum Foreseeable Loss, (MFL), based on Baker‘s blast technology for Detonations and Deflagrations as applied to plant equipment layout. n There is a trend toward higher insurance premiums as insurance companies adjust their actuarial data. n Many chemical companies may follow Exxon’s trend to insure themselves.

End Of Show n Your Department should have a copy of the 7 th Edition available for further examination and application to your projects.