Runaway exothermic reaction
Batch chemistry that gets away: cooling failure, mischarging and accumulation against layers of protection ending in relief and quench.
4 threats 13 barriers 3 consequences safety-critical barriers marked
Use this template free. Copy “Runaway exothermic reaction” into your own workspace and adapt every barrier — no credit card.
Start free with this template →Threats & preventive barriers
Each threat is a credible pathway to the top event; its barriers interrupt that pathway before control is lost.
Loss of cooling (utility or pump failure)
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Redundant cooling water supply ★ critical
Passive (hardware) · 85% effective · Owner: Utilities Engineer
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Low-flow alarm with operator response
Socio-technical · 75% effective · Owner: Control Room Supervisor
Alarm flooding during upsets
Mischarging of reagents (wrong amount or order)
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Automated dosing with batch interlocks ★ critical
Active hardware · 88% effective · Owner: Process Control Engineer
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Two-person verification of charges
Behavioural (human) · 65% effective · Owner: Shift Supervisor
Time pressure at shift change
Agitator failure causing accumulation
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Agitator monitoring with auto feed-stop ★ critical
Active hardware · 85% effective · Owner: Process Control Engineer
📅 Interlock proof test · semiannual keep-alive task
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Preventive maintenance of agitator drive
Socio-technical · 75% effective · Owner: Maintenance Lead
📅 Drive inspection · quarterly keep-alive task
Raw material quality deviation
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Incoming QC with certificate of analysis
Socio-technical · 80% effective · Owner: QC Manager
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Supplier qualification programme
Socio-technical · 70% effective · Owner: Procurement Lead
Consequences & recovery barriers
Once the top event happens, recovery barriers limit each consequence.
Reactor overpressure and rupture
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Emergency relief system sized for runaway ★ critical
Passive (hardware) · 90% effective · Owner: Process Safety Engineer
📅 Relief device inspection · annual keep-alive task
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Emergency quench / inhibitor injection ★ critical
Active hardware · 80% effective · Owner: Process Control Engineer
📅 Quench system proof test · semiannual keep-alive task
Toxic release to site and neighbours
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Scrubber on relief discharge
Passive (hardware) · 75% effective · Owner: Environmental Engineer
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Community alert & shelter procedure
Behavioural (human) · 70% effective · Owner: Emergency Coordinator
Batch and asset loss
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Post-trip recovery procedures
Socio-technical · 75% effective · Owner: Production Manager
Copying this template gives you a fully editable bowtie: barrier owners arrive as role suggestions, escalation factors sit on their barriers, and keep-alive activities are scheduled from the moment you copy. New to the notation? Read what the bowtie method is or browse the practical guides.
Use this template free. Copy “Runaway exothermic reaction” into your own workspace and adapt every barrier — no credit card.
Start free with this template →