Effect of Temperature Changes on Water‐Main Breaks

The principles of temperature‐related stresses are discussed. Statistical evidence of temperature effects on water‐main breaks are also presented from the Washington (D.C.) Suburban Sanitary Commission's experience. A strong correlation was found between water temperature and main break activity. The temperature drop was shown to be a significant factor. A new low in the water temperature resulted in a sharp increase in the number of main breaks. The breaks were mostly circular and occurred on grey cast‐iron pipes ranging in size from 76 mm (3 in.) to 203 mm (8 in.) A failure mechanism is presented to explain the complex nature of temperature related main breaks. The mechanisms explains why break activity is not uniquely related to the temperature. It also shows how different break activities may occur under similar temperature‐drop conditions. The complex nature of temperature‐related water‐main breaks does not lend itself to a simple forecasting model. However, a practical and simple procedure is presented that may be used to provide advanced warning of high break activity. This information helps the utility manager to prepare for the heavy repair demand on the maintenance crew.