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Selecting an ERS Design Basis. SACHE Workshop Gary Van Sciver September 20, 2005. E mergency R elief S ystem. Vessel Overpressure. Concept Sciences. 1999 Allentown, PA 5 fatalities high concentration and temperature of hydroxylamine. Hazardous Release. Phillips.
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Selectingan ERSDesign Basis SACHE Workshop Gary Van Sciver September 20, 2005
Concept Sciences 1999 Allentown, PA 5 fatalities high concentration and temperature of hydroxylamine
Phillips Pasedena, Texas 1989 23 fatalities Vapor cloud explosion of ethylene and other gases Explosion occurred ~ 2 minutes after release started
Bhopal Union Carbide 1984 2,500 fatalities large ERS release of methyl isocyanate
Venting Policy: ERS must protect on-site people AND off-site people
Failure Scenario: Series of events leading to high vessel pressure.
Codes require that the maximum pressure not exceed the vessel design pressure
Design Basis: Most severe failure scenario which complies with the Codes.
Procedure: 1. Identification 2. Selection
Non-Reactive Checklist 1. Heat addition a. Normal breathing b. Fire c. Excessive heating 2. Pressurized liquid addition 3. Pressurized gas addition
1a. Normal breathing(atmospheric temperature and pressure changes)
2. Pressurized liquid addition(usually accompanied by some flashing, especially if hot)
3. Pressurized gas addition(line blowing, pressure transfers, pads or purges)
Reactive Chemistry Worksheetdeveloped by EPA and NOAA (National Oceanic and Atmospheric Administration)http://response.restoration.noaa.gov/chemaids/react.html
OSHA Chemical Reactivity Websitehttp://www.osha.gov/dep/reactivechemicals/
NormalReaction Checklist 1. Inadequate cooling 2. Inadequate heat sink 3. Excessive reactant 4. Poor reactivity
Abnormal Reaction Checklist • Too hot • Wrong composition
2. Selection(of a design basis from the important failure scenarios)