96-11: Strength-Degredation Based Life Expectancy of Wood Cooling Towers

Life expectancy predictions of wood cooling towers are accomplished with the aid of nondestructive and/or destructive testing of representative samples of structural members and their connections. Based on the test information on the current condition and the original design stresses, rates of strength degradations are computed for critical components. The degradation rates, combined with structural analysis, are used to project a life expectancy of the tower at a given level of probability. Examples of evaluations of current conditions and life expectancy projections are provided for cooling towers owned by Appalachian Power Co., Northern States Power Co. and Potomac Electric Power Co.