Canadian Pipeline Standards and Regulations: CSA Z662

What are the CSA Z662 Regulations and Why are They Important?

In 2019, the Canadian Standards Association (CSA) released the 8th edition of Standard Z662: Oil and Gas Pipeline Systems. This most recent edition included a wide range of impacts on the energy industry with a combination of new and updated requirements, thereby identifying 18 significant changes from the 2015 edition.

The key changes made that are of significance to operators and impact pipeline systems include the following: 

Class Location 

Class Location is defined as a geographical area that is classified according to its approximate population density as well as other characteristics that are considered when designing and pressure testing piping in a specific area. It provides a means of ensuring that the operating and design parameters of a pipeline are appropriate for the population density at every point along the pipeline route. Class locations are divided into four different categories intended to reflect different levels of population density. The only change in the 2019 edition is the addition of the 120-person occupancy threshold for buildings in Class 2. Previously buildings occupied by 20 or more people could be classified as Class 2, however, for 2019, criteria have been added where any building occupied by more than 120 people during normal use must now be classified as Class 3.

In addition, previously class locations for an area were calculated based on a measurement of 200m on either side of pipeline (for a total width of 400m) and 1600m (or 1 mile) along the length of the pipeline. For 2019, the assessment area width for gas pipelines (excluding CO2) is now equal to the greater of 60m (for sweet service) or 400m (for non-sweet service).

The 2019 edition of CSA Z662 has added criteria for Low Vapor Pressure (LVP) to distinguish between liquids with low and high flammability, with high flammability defined as having a flashpoint less than 38°C. This distinction results in a major change to the standard, where the LVP high flammability location factors for Class 3 and 4 decrease from 1.000 to 0.800. This 20% drop for location factor could have serious implications for LVP pipelines and necessitate substantial pressure reductions or even pipe replacements for existing pipelines.

Designated Geographical Areas (DGA) 

Designated Geographical Area (DGA), as introduced in 2019, is a new concept to CSA Z662 and will be of particular interest and importance to operators of LVP liquid pipelines (excluding fresh water). At a high level, DGAs are water bodies where a pipeline release could have serious consequences. As such, CSA Z662-2019 requires that LVP pipeline operators determine what constitutes a DGA while taking into consideration all the following:

  • Disruption to commercial navigation activities
  • Use as a major drinking water or food source
  • Presence and type of fish species
  • Reliance of endangered or protected species on use of the water body

In tandem with the criteria noted above, LVP pipeline operators will be required to identify pipeline segments where a release could adversely affect a DGA, while weighing the impact of:

  • Terrain and environment surrounding the pipeline
  • Presence of waterways or ditches that could serve as pathways
  • Flow characteristics of the release fluid over land or on water
  • Potential release volume including consideration of likely failure modes
  • Emergency response plans

The Z662 standard states DGAs are to be considered separately from Class Location, with LVP pipeline segments identified as potentially impacting a DGA using a location factor not to exceed 0.9. This could present challenges for operators like those discussed pertaining to the reduced location factors associated with the updated Class Location requirements in CSA Z662-2019. Establishing a consistent and well-defined process for determining DGAs will be key, which could be mitigated by information-sharing amongst LVP pipeline operators.

Records Retention 

CSA Z662 introduced a new requirement (Section 4.1.11) which states that all design documents and records must be maintained for the life of the pipeline system. The new clause lists a series of documents and records including:

  • Engineering Assessments
  • Materials Specifications
  • Class Locations
  • Basis for valve location and spacing
  • Basis for stress and support calculations
  • Basis for pipe cover and clearance
  • Basis for compressor and pump station design
  • Others

While most, if not all, operators already keep these documents and records as standard practice, it is now a requirement with CSA Z662 that all existing records be maintained for the life of the pipeline system, even for pipeline systems designed prior to the release of the latest edition.

Engineering Assessments 

The Z662-2019 standards also include some updates with respect to engineering assessments and the criteria they are required to consider, such as:

  • Depth of cover
  • Presence of crossings
  • Presence of and proximity to other facilities
  • Loads and interacting loads
  • Potential presence and significance of undetected imperfections

These new requirements may already be factored in as part of existing operator specified engineering assessment criteria.

Dent Assessment Criteria 

There have been updates to the 2019 standard pertaining to dent assessment criteria as outlined in Clause This clause includes changes in the new edition which provide guidance on which dents shall be considered as defects unless determined by an engineering assessment to be acceptable.

For dents interacting with welds which are >6mm in depth for pipe with outside diameter 323.9mm or smaller, criteria have been added to exclude those dents with measured curvature strain <4% and which pass non-destructive inspection for the interacting portion of the weld. This addition will provide operators with some newfound flexibility when determining which dents qualify as defects

On the flip side, criteria have been added to the clause to account for the effects of pressure cycle fatigue when identifying potential defects. This addition will require that operators include pressure cycling as part of any engineering assessments to determine whether a dent should be considered a defect.

Annex N (Guidelines for Pipeline System Integrity Management Programs) 

CSA Z662-2019 updates also includes a restructuring of Annex N, primarily intended to be more relevant to facilities. While this annex continues to be informative as opposed to mandatory, it continues the trend of increasing regulatory focus on not just pipelines but their associated facilities as well.

Given Annex N specifically addresses management systems, the update also highlights the importance of establishing comprehensive integrity programs with clearly defined processes and procedures that have been implemented and documented. The work involved in establishing and implementing integrity programs will vary greatly between operators and be dependent on their pipeline-related infrastructure as well as the maturity of their integrity programs. Some companies with mature integrity programs may only require minor updates or modifications, however for many companies where these programs are still being developed, especially with respect to facilities, significant time and effort could be required to develop and implement programs. In these circumstances, Annex N, while informative, provides an excellent framework for all companies to work towards. To learn more about the CSA Z662 standards and current updates, please contact us or view our whitepaper exploring “The Impacts of CSA Z662 Regulations for Canadian Pipeline Operators” — link to whitepaper here: The Impacts of CSA Z662 Regulations for Canadian Pipeline Operators.