Updated June 2022
We rate the effect of an incident as being high, medium, or low. A definition of the incident consequence ratings is provided in the glossary.
We classify each pipeline incident into one of the following five types:
- gasket, seal, packing gland, or threaded fitting (GSPT) release
- installation leak
Not all incidents result in a pipeline failure. A failure means the pipeline cannot contain the substance being transported (i.e., a leak or rupture). Incidents include events where contact (hit) with a pipeline occurs, but no substance was released.
Leaks and Ruptures
Pipeline leaks and ruptures are collectively referred to as pipeline failures and typically result in a substance release. Pipeline ruptures immediately impair pipeline operations, whereas pipeline leaks may not. However, pipeline leaks typically cause the largest spills because they can go undetected for long periods. Consequently, leaks and ruptures are reviewed thoroughly to help identify causes and trends, which helps us with industry education and prevention.
A hit is when a pipeline is damaged from contact during a ground disturbance but does not release a substance. Any person or company that damages a pipeline in Alberta while conducting a ground-disturbance activity must report the incident to the AER so that we can inspect the site to see if it is safe, that the pipeline has not been compromised, and that corrective action has been taken to prevent future occurrences.
All companies must be registered with Utility Safety Partners (formerly Alberta One-Call), which helps excavators identify underground infrastructure within their dig area. Most pipeline hits are caused by the operators themselves when excavating, digging, trenching, or conducting other forms of ground disturbance near an existing pipeline. Under the Pipeline Rules, permission from the pipeline owner is required when working near an existing pipeline to reduce the chances of such an event.
GSPT releases are always aboveground releases and rated as a low consequence because very low volumes are released. GSPT releases usually occur at a gasket, seal, packing gland, or threaded fitting and can be addressed by replacing the problematic gasket or seal or making routine mechanical adjustments, such as tightening bolts. Although these are typically maintenance issues, they are reportable incidents as per the Pipeline Act.
Installation leaks are leaks from equipment installed at an auxiliary site associated with a pipeline, such as a compressor, pumping station, tank farm, or meter station listed as an installation on the pipeline licence.
Figure 4 shows the breakdown by incident type.