"Molten metal spilled..."

Out of all the hazards in the aluminium industry molten metal explosions have the potential to cause the greatest damage. Our industry has done a great job acknowledging the hazard and worked diligently to educate. This incident emphasizes the importance of plant education. This story came from a July 2014 newspaper posting of a local fire department radio report. The report lacks detail so the company name and location has been omitted. Here is the story:

A small amount of molten aluminum spilled at an aluminium and started a small fire. There was little damage.

A “small amount of molten metal” can vary widely depending which type of facility. A foundry may consider a small amount of molten metal to be less than 100 kg. Whereas a primary plant may consider a few tonnes to be a small amount of molten metal. Either way, our industry’s history is littered with incidents involving small and large quantities of molten metal which have either exploded or caused fires. Resulting in injuries and fatalities.

This aluminium plant considered a small molten metal spill in the range of 15-20 tonnes. The “little amount of damage” was damaged caused to some electrical conduit and control boxes under the furnace.  Congratulations to the unnamed plant on acknowledging the seriousness of the issue and containing the hazard. This facility no doubt has an excellent management and safety team that has put forth the importance of safety education.

The question that the Aluminium Plant Safety Blog puts forth to the readers is:

Where does a molten metal spill go to?

Molten aluminium is a liquid, albeit a very hot liquid. Any liquid when spilled will flow to the lowest point (if allowed). In many of our facilities the lowest point is either a casting pit, maintenance pit, or under a furnace. There have been numerous incidents where molten metal flowed to the maintenance pit under a furnace coming into contact with moisture, on bare concrete, steel or stainless steel resulting in a catastrophic explosion. Our industry’s best safety practices are to coat any bare substrates that have the potential of coming into contact with molten metal with an approved safety pit coating. Here is a link to the industry’s standard for safety pit coatings (here).

Unfortunately, there are some facilities that operate under a false safety belief that their current practice of not using an approved safety pit coating is fine. That false belief is rationalized by either the statement “we’ve never had an explosion”, or simply a lack of knowledge. The APSB has visited too many facilities who claim that they have never had an explosion. But when the APSB questions why there is dried molten metal on the bottom of the roofing (25 meters above the casting pit) the plant personnel have no answer. The facilities that have a lack knowledge are at least welcome to new safety information. Either way, safety pit coatings need to be applied wherever molten aluminium can come into contact with bare concrete, steel, and stainless steel.

The Aluminium  Association (US) has been at the forefront of molten metal safety in our industry for decades. Their Casthouse Safety Workshops held biannually cover molten metal safety issues.

The next Casthouse Safety Workshop will be held the week of October 27 in Nashville, Tennessee. More information can be found here in the near future (here).

The Aluminium Association’s “Guidelines for Handling Molten Aluminium” is considered to be the industry’s best practices. It can be obtained here.

The importance of incorporating the local fire department in your plant’s safety training has been repeatedly made by the APSB. We are confident that the local fire department in this incident who provided assistance had cooperated and participated in the aluminium plant’s safety program and were well aware of the hazards. As well as the current industry procedures for dealing with molten metal. The Aluminium Times this month had an article about the incorporating the local emergency management services in training. 

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