The Case of the Cooties in the Cooling Tower
Synopsis:
In this case, “Truth is in the Details” is well demonstrated where a building owner insisted that a leaking cooling tower was the result of freezing, but Boreas was not to blame.
Background:
A large corporate office building required cooling all year as a result of high occupancy and extensive employment of personal computers as well as a large data center. During cold weather a number of leaks were found in an 8’ x 8’ x 18’ long tube bundle of the cooling tower and it was claimed that it was damaged by freezing, and unrepairable.
Analysis:
TI was requested to determine the cause and extent of damage. TI found that the tube bundle had over 1.4 miles of oblong, galvanized steel tube in the tube bundle. Some leaks were found near the outside of the tube bundle and sections were cut out for initial laboratory analysis. It was determined that none of the leaks in the initial samples were the result of freezing but of MIC – Microbiologically Induced Corrosion, a condition where, in the face of inadequate closed circuit water additives, aerobic bacteria first create blister-like colonies along tube seams. Then, anaerobic bacteria take up residence within the blisters where they are sheltered from oxygen and can feed on the waste products of the aerobic bacteria, producing their own highly acidic waste products. The anaerobe waste products chemically bore holes through the side of the tube, resulting in the leaks.
The owner insisted that at least some of the leaks were due to freezing and insisted the claim be paid. TI took possession of the tube bundle and through pressure testing found all leaks and cut out all leaking tube sections. All leaks were found to be the result of MIC. Further, TI performed laboratory freeze testing on the oval tubes and found that they could withstand at minimum three incidents of freezing solid because of the oval cross-section of the tubes.
Each successive freeze moved the oval cross-section more toward round and only when round could an additional freeze burst the tube. Precision measurements were taken after each freeze step documenting the dimensional change and the dimensions of each leaking tube section were taken, showing that none of the leaking tubes had ever been frozen.
