Many threats to the integrity of a system are time-dependent. That is, as time goes on, the greater the threats become. TransGas has taken and continues to take steps that will lessen these threats.

Our Integrity Management Program is comprised of three main components:

1. Prevention - protecting piping and pressure vessels from conditions that may lead to integrity concerns;
2. Detection - finding defects that may lead to integrity concerns; and
3. Mitigation - repairing or implementing risk-reduction controls.

Ultrasonic Inspection of the pipe wall.

The Integrity Programs will focus on risk control in the following areas:

• Facilities near high consequence areas;
• Pipelines, piping, and pressure vessels where results of inspection programs indicate a possible concern; and
• Pipelines and piping where the effectiveness of cathodic protection is low or coatings are damaged or deteriorated.

A. Integrity Inspections
Using sophisticated devices commonly called electronic pigs or in-line inspection (ILI) tools, TransGas inspects hundreds of kilometres of pipeline every year. Specialized electronic pigs are placed inside our pipelines and travel the entire pipeline length. The tool gauges wall thickness, defect size, dent shape and size, geometry, and metal loss. Information is stored in the tool and then cross-referenced with a location using a satellite positioning system, to within one metre of accuracy.

Field staff prepares a "smart pig" for launch.

Engineering Assessment of Inspection Data
 

After gathering data, our employees work with experts to analyze and diagnose pipeline anomalies. Mitigation and repair plans are developed and implemented specific to the concerns identified on each inspected pipeline.

Our in-line inspection (ILI) program began in 1997. By the end of 2005, 3,457 km of pipeline has been inspected with ILI. By the end of 2007, TransGas will have inspected major system pipelines representing approximately 25% of our pipeline network.

Also, considerable amount of inspections are conducted on station piping and pressure vessels and this activity will increase as new programs are developed.

To date, approximately 85% of the total TransGas operational pressure vessels have been visually inspected.

B. Stress Corrosion Cracking

Stress corrosion cracking (SCC) is cracking arising from the combined actions of stress in the pipe steel, a corrosive environment around the pipe and susceptible pipeline material. Under specific conditions, what starts as a hairline crack on the outside of the pipe can progress into a cluster or colony of cracks. These cracks may join together and deepen to the point where they may grow through the entire wall thickness. TransGas has had some encounters with minor SCC on our system that were immediately remedied.

Inspectors document the pipe surface conditions.

C. Cathodic Protection
Cathodic protection is an induced electric current on the pipeline that protects it from metal loss. Every month, a voltage reading is taken to ensure it's at an appropriate level.

D. Surveys

Over time, the implementation of modern technology on pipeline construction and maintenance, combined with our Integrity Program, has dramatically reduced leaks on the system.

E. Crossings & Encroachments
A key component of our integrity management program is coordinating any activity that encroach on our pipelines. Anytime this occurs, precautions are taken to eliminate any third-party contact with the pipeline. We also take the necessary precautions to protect our cathodic protection system.

If you are planning excavation work, please call Sask1stCall TransGas’ annual average for the past 10 years is 2.2 reported pipeline hits per year.

TransGas recorded 0.14 pipeline contacts for every 1,000 km of pipeline in 2005.