A room in a medical facility experienced corrosion of installed finishes and a multi-million-dollar piece of equipment during construction. A PVC pipe was cast into the concrete floor slab to provide a conduit for later-installed copper gas tubing. Prior to installing the copper tube, the interior finishes, including stainless steel cabinets, galvanized steel electrical boxes, leaded glass windows, and medical equipment were installed in the room. Subsequently, copper gas pipe connections were brazed where they penetrated the concrete slab, at the location of the PVC pipe. Incidental heating of the adjacent PVC pipe led to the production of hydrogen chloride, and deposition of a film of hydrochloric acid on the surfaces within the room. This case study describes the corrosion of the materials within the room related to off-gassing of hydrochloric acid from excessive heating of the PVC pipe during brazing of the copper. Studies involved on-site evaluation and microscopy, laboratory evaluation of deposits using x-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy dispersive x-ray spectroscopy.