Transmission pipelines are constructed with pressure tested steel and covered with a protective coating to prevent corrosion. The Company utilizes a 24-hour per day Gas Control Centre with computer control of its pipeline system, commonly referred to as SCADA (Supervisory Control and Data Acquisition) to aid in the safe operation of its system. This system allows pipeline operations staff to monitor pipeline flow, pressure conditions and trends, to start and stop compressor units, and to open or close pressure control valves - all from a central control center. The SCADA system is capable of detecting and correcting various events that could impact system integrity. Unusual conditions trigger alarms to which field staff respond to verify problems and take corrective action if necessary. The Company also conducts regular aerial and land surveillance of the pipeline to check for corrosion, leaks, vegetation, and development encroachment.