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Clean Hydrogen Partnership

Hydrogen fire when testing a rocket engine

Event

Event ID
630
Quality
Description

At a rocket engine testing facility, a combustion experiment of the pre-burner (gas generator for driving the turbopump) was being conducted, before testing the turbopump. The pre-burner is the gas generator for driving the turbine. In the course of the experiment, hydrogen gas leaked from the flange of the supply pipe connecting the high-pressure hydrogen storage and supply facility and the pre- burner and was ignited by the igniting element of the pre-burner.

Event Initiating system
Classification of the physical effects
Hydrogen Release and Ignition
Nature of the consequences
fire
Macro-region
Asia
Country
Japan
Date
Component involved
flange (bolts)
Failure mode
leak
Initiating cause
manufacturing defect/error
Root CAUSE analysis

The INITIATING CAUSE was the failure of a flange due to a defective bolt. 

The post-incident investigation of the bolt of the flange, suggested a manufacturing defect as the ROOT CAUSE.

Root causes
Date entry in HIAD
01/05/2025

Facility

Application
Non-road vehicles
Sub-application
Aerospace
Hydrogen supply chain stage
All components affected

H2 engine

Process temperature range [C]
Ultra-high temperature (above 1000°C)
Process pressure range [MPa]
unknown
Location type
Unknown
Location
industrial area
Operational condition

Emergency & Consequences

Number of fatalities
0
Number of injured persons
0

In-depth data

Release type
gas
Involved substances (% vol)
H2 100%
Probable IGNITION SOURCE

References

Sources categories
KHK
Reference & weblink

High Pressure Gas Accident Cases Database of the KHK (High Pressure Gas Safety Association): https://www.khk.or.jp/public_information/incident_investigation/hpg_incident/incident_db.html (accessed May 2025)

The first entry in HIAD was coming from RISCAD, which is now closed.