AP/wideworld

Welders cutting steel for a walkway inside the roof wall apparently ignited the EIFS that gives the building its architectural details. The synthetic stucco system consists of three layers: an inner layer of foam insulation board is attached to the structure with adhesives or mechanical fasteners; it then is covered with a cement and polymer base coat reinforced with fiberglass mesh, which is covered with a textured finish coat.

The damage at the 3,002-room Monte Carlo is not as bad as it could have been because it was extinguished relatively quickly. But the spectacle of fire spreading along the top four floors brings back memories of the MGM and Hilton fires in the 1980s that killed scores of people. Those fires led to many changes in Las Vegas building codes.

Related Links: Don't Malign EIFS 2/20/2008

The same should happen with this fire. The Monte Carlo opened in 1996 and was built according to the 1991 Uniform Building Code, which is virtually the same as the 2006 version now in effect with regard to EIFS. Samples of the burned facade have been sent to labs for testing.

Building officials say it is premature to say what the effect on codes might be. But the Clark County (Nevada) Buildings Dept. reports that the EIFS foam core shrinks back from its coat at 250°F to 275°F and starts to melt at higher temperatures. At about 650°F, the liquid foam becomes flammable.

Investigators say the welders on the roof did not have the proper mats to capture the molten metal produced by their work, and their employer did not have the proper "hot" permit. Weld metal can reach 1,000°F, clearly hot enough to be an ignition source.

The Monte Carlo fire shows that even a concrete building with EIFS can burn like a torch under certain conditions. That should be a warning to everyone using the construction material, whether the code change is needed or not.