Underground Cellular Glass Pipe Insulation Failures in Quebec and Louisiana

The author has participated as an expert witness on two major failures of the subject insulation on steam/condensate piping. One installation was in Quebec and one installation was in central Louisiana. The two systems were very different in design and installation. In both cases the water table was occasionally above the pipes. The soil in Louisiana was clay. There were no expansion nor anchoring provisions. The water-proofing consisted of multi-layers of cutback asphalt mastic and glass mesh reinforcing. The solution was to relocate the piping above ground. The soil in Quebec was clay except that the piping was in sand fill or a sand trench. There were many drainage ditches on the site — some of which were well below the level of the pipes. Dewatering pumps were installed in the trench in an attempt to save the insulation. The waterproofing system was designed and installed in strict accordance with the manufacturer's directions and under the supervision of the manufacturer's technical service representative.