Non-corrosive containment vault

Abstract

A sealed underground containment vault has an outer shell made of non-biodegradable plastic such as polyurethane or polypropylene. The vault has a containment compartment defined by a bottom wall, and sidewalls and endwalls extending upwardly from the bottom wall. A container, such as a casket, is placed within the lower containment compartment. The outer shell for the lower containment compartment has an upper edge portion that extends completely around the upper edge of the lower compartment. A fusible element, such as an outwardly extending plastic flange, is provided around the upper edge portion completely around the lower containment compartment. A cover for the vault has an outer shell that includes a lower edge portion, which likewise has a fusible element extending completely around the lower edge portion of the cover. The fusible element on the outer shell for the cover mates with the fusible element of the outer shell on the lower containment compartment when the cover is placed on the lower containment compartment. Heat and pressure are applied to the mated fusible elements to weld them together, thereby creating a permanent water-tight and air-tight seal. The lower containment compartment and cover preferably have an inner and outer shell with foam filled in between the inner shell and the outer shell, and also a frame structure between the inner shell and the outer shell.