Fire due to lightning

Event

Event ID: 46
Quality: 2
Description: Lightning caused fires at a plant near Hamburg after igniting a hydrogen mixture release through a ventilation pipe
Event Initiating system: Hydrogen System Initiating Event
Classification of the physical effects: Hydrogen Release and Ignition
Nature of the consequences: Fire (No additional details provided)
Macro-region: Europe
Country: Germany
Date: 09/06/2004
Main component involved?: Venting System (Exit)
How was it involved?: Ignition Of Vented H2
Initiating cause: Extreme Environmental Conditions (Lightning)
Root causes: Environment
Root CAUSE analysis: INITIATING CAUSE and ROOT CAUSE was the ignition in air of the hydrogen vented through a vent stack.

Number of injured persons: 0
Number of fatalities: 0
Emergency action: No evacuation.
Isolation of the pipeline segment and its de-pressurisation.

Lesson Learnt: This is an example of 'lack of lessons', due to lack of details. In this sense, this case is instructive, as many other with Quality 2, becasue it highlights what is needed for an analysis.
Nothing is known on the operative conditions which brought to the creation of a flammable mixture near the vent exit. Was it a normal venting operation or an emergency venting due to the shutdown of some unit? In the former case, was formation of a flammable mixture part of the safe design? Was the electrical grounding of the vent and protection against lighning correct and effective?
How often did a lightning strike without conseequences?
And finally, did the plant management introduce improvements aiming at reducing the probability of this type of events?

Reference & weblink: HIAD 1.0 reporting template (Original source unavailable).