Two, dry chemical air pollution control reactors serving an industrial coal fired boiler suddenly collapsed, for a loss of approximately 10 to 12 feet of vertical height. Fortunately, no one was injured, but the plant was immediately shut down, and remained down for weeks, resulting in substantial loss in production and revenue. The plant filed an insurance claim for the equipment loss and the business interruption loss.

A forensic investigation for the insurer evaluated the cause of the loss and potential liabilities by the equipment manufacturer and equipment maintenance contractor.

Initial demolition steps revealed signs that the vessel walls had collapsed due to corrosion, so a metalurgist was hired to assist in the forensic investigation. The plant owner also sent an in-house metalurgist to conduct an investigation.

The lessons of this case highlight several key elements in conducting a forensic investigation. Defining the scope of the investigation and gaining access to the information, people, locations, equipment and samples needed will be discussed. Information about the reactor processes and maintenance of the equipment were evaluated. A detailed plan for collecting and evaluating sample coupons and samples of scale deposits from the reactor walls was developed. The scene and the failed equipment were carefully documented and photographed. Ultrasonic wall thickness measurements were collected. Corrosion patterns were studied. Operating conditions that could have led to the corrosion patterns were evaluated. Legal issues and concerns also affected the investigation.