The electric power industry uses SF6 to insulate high voltage lines, circuit breakers and other equipment used in electricity transmission and distribution. In order to minimize the risk of equipment failure associated with arcing, the amount of water vapor in SF6 gas should be kept at minimum. Therefore, dewpoint measurement is an important part of the maintenance of SF6 containing equipment.

The Vaisala DM70/DMP74C is a lightweight, battery powered hand-held instrument for economically measuring dewpoint in SF6. Fast response time and internal datalogging optimize the field technician's time. A unique sample cell allows dewpoint measurement in gas pressure or in ambient pressure and protects against accidental discharge of SF6. Long term reliability and accuracy are assured by patented Autocalibration technology.