In This Issue

Advisory Bulletin (ADB-03-09) Re: Potential Service Disruptions in SCADA Systems

The Office of Pipeline Safety recently issued the following notice and gas and liquid pipeline operators. For a complete copy of the notice, please contact our Vice President of Business Development, Dan Shelledy, at

Each pipeline owner or operator should review their procedures for the upgrading, configuring, maintaining, and enhancing its SCADA system. If not well thought out and thoroughly tested, such changes could cause inadvertent service disruptions in the SCADA system. Resulting conditions could may impede controllers responsible for operating the pipeline from promptly recognizing and reacting to abnormal conditions, and could potentially impact the controllers’ abilities to restore normal operations. Owners and operators should ensure that SCADA system modifications do not degrade overall SCADA performance to an unacceptable level. To further reduce the potential effect of service disruptions, responsible personnel should coordinate significant and non-routine SCADA modifications to occur at times when no significant changes to pipeline operations are anticipated.

It is good practice for owners and operators of pipeline systems to periodically review their SCADA system configurations, operating procedures, and performance measurements to ensure that the SCADA computer servers are functioning as intended. Owners and operators should consider using off-line or development workstations/servers to help ensure that impending changes are tested as thoroughly as possible before moving the changes into production. Although off-line or development workstations can be valuable, they may not fully represent timing, load and other factors that will be present in the production environment. System modifications should be implemented via structured and managed processes to reduce the likelihood of unforeseen problems. Such controlled processes are especially important if an owner or operator makes changes directly in the on-line environment.

In addition, owners or operators should periodically confirm that associated design and maintenance personnel, whether employees, contractors, or third-party providers, are adequately skilled to perform SCADA system modifications without causing undesirable consequences. These same personnel should be cognizant of the critical system attributes that should be monitored during the testing phase of implementation.