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Ed Yeates reporting Sunday night's plant explosion in Provo was a full-scale version of what some of us may remember from high school chemistry classes. Tonight, a local fire and explosion expert shows what may have gone wrong at Pacific States Cast Iron Co.
Water is usually our friend in a fire, but in this case it was the enemy. It's sort of like a chemistry experiment gone bad, but on a much larger scale.
On a casting floor, a frozen pipe leaked water, which came in contact with calcium carbide (a compound used on iron pipe to keep it from breaking so easily). The stuff stores well as long as you keep it dry.
In a table-top experiment, if you add calcium carbide to plain water, the mixture suddenly becomes volatile. "Calcium carbide reacts vigorously with water to make acetylene gas, and in the absence of a spark or a flame it would be just a clear colorless gas," explained Dr. Charles Wight, of the University of Utah's Center for Simulation of Accidental Fires and Explosions.
Let that gas come in contact with a spark and now you've got flames. Acetylene is a hot, fiery gas that, when controlled, is a tool in the hands of builders and welders. But if it accumulates in a room or a building, watch out.
"In many respects, acetylene is very similar to natural gas, but one of the differences is it makes soot very early. So acetylene--when it's not at very high temperatures, flames like in an acetylene torch--makes lots and lots of soot," Wight said.
Wight studies accidents like this all the time and says this one in particular is not common and should never have happened. "That seems like an easy fix to design in a plant so you wouldn't have a water pipe anywhere near the storage area for calcium carbide," he said.
The University of Utah center dissects accidental fires and explosions hoping to give industry ways to prevent them. It has applied for a grant to do not just computer simulations, but full-scale simulations as well.
