Question 115General Subjects - Assistant Engineer

The correct answer is C) Steel ruler or tape measure. When retightening the plate type heat exchangers, a steel ruler or tape measure is required to ensure the proper tightening sequence and torque values are applied. This is necessary to maintain the proper seal and prevent leaks in the heat exchanger. The other options, such as a torque wrench (A) or pneumatic impact wrench (B), are not appropriate for this task, as they would not provide the necessary precision and control required when retightening the heat exchanger plates. A cantilever wrench (D) is used for different types of maintenance and would not be the correct tool for this specific operation.