Cooling Power Loss in a Foundry
This near miss occurred at metal smelting unit of a foundry. At 9:45 a.m., due to a power outage, the cooling pumps of two furnaces containing nickel and chromium stopped. One of the two furnaces was at the end of the smelting cycle. The temperature of the metal was 1300C. Due to the stop of the cooling system, water from the public network took over the cooling function, but was not efficient, causing the cooling coil to overheat. At this point, the risk was a contact between the molten metal and the water contained in the coil, which could have generated hydrogen, its ignition followed by an explosion. Therefore, the operator triggered the evacuation alarm and alerted the firefighters.The emergency services provide external cooling with water and perform natural ventilation followed by mechanical ventilation. After approximately two hours, the furnace cooled, the metal froze and the risk of explosion avoided. After additional two hours, the firefighters' intervention was over.
Event Date
January 24, 2023
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes (Select all applicable options):
Cause Comments
The initiating cause of the event was a malfunction in an electrical cabinet, which caused the shutdown of the 380 V power supply to the plant. Due to the lack of power, the cooling pumps of the melting furnace stopped. The replacing flow of city water was insufficient to stabilize furnaces temperature because a valve was not fully open. Nobody verified the operation of this valve, because the attention of the personnel was focused on the electrical failure.
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
metals furnace, colling coils
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
The near miss occurred following a power cut.
Lessons Learned
After the event, the operator adopted the following corrective measures: changed the water inlet valve so that its opening could be easily checked; revised its check lists in case of an incident; implemented training to improve responsiveness and targeted more frequently exercises; prioritised cooling above any other action in the event of an incident.
Emergency Action
Therefore, the operator triggered the evacuation alarm and alerted the firefighters. A 150 m security perimeter was set up, resulting in the confinement and evacuation of 6 homes and 115 people (employees and residents). Two bus lines were diverted and the traffic on the nearby road interrupted. The emergency services provide external cooling with water and perform natural ventilation followed by mechanical ventilation. Around 11:30 a.m., the furnace cooled, the metal froze and the risk of explosion avoided. Around 12:30 p.m., staff was authorised to return to the premises to take their personal belongings and leave the site. Around 1:30 p.m., the firefighters' intervention was over.An interruption of work of 4 days was decided for 90 people.
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References