Ask Our Expert Blog Series: Han Wu

Canadian Standards Association (CSA) Z662 Proposed Updates: Safety Class (Annex C)

What are the main updates for your respective CSA Z662 regulation focus area?

The CSA Z662 Class Location Task Force (CLTF) has developed proposed, safety-class based pressure design approach for the 2023 Standard under the non-mandatory Annex C. It is currently out for public review and the intent is that it can be used as an alternative to the current Clause 4 pressure design approach. The safety class system is a risk-based approach that considers safety and environmental consequence drivers, pipeline attributes, and service fluids. It has been calibrated to ensure consistent risk levels for all onshore pipelines in all safety classes for both new and existing pipelines. The following table outlines each safety class and its associated allowable failure probability:

Safety Class 1 2 3 4 5 6
Failure Consequence Severity Very Low Low Medium High Very High Extreme
Allowable Failure probability (per km-year) 10-3 3 × 10 4 3 × 10-5 3 × 10 6 3 × 10 7 3 × 10-8

What is the intent behind these changes for the industry to be aware of?

The intent behind CSA Z662 developing these proposed updates is to transition from the current class location based pressure design to a new risk-based safety class system for pressure design. Following are some examples of benefits to highlight:

  • Consistency of risk levels for onshore all pipelines
  • Accounts for various service fluids without needing separate groupings and the pre-defined conservatism used in the current standard
  • Factors associated with roads and railways are based on quantitative considerations
  • Possibility to reduce design conservatism through adjustment factors such as enhance damage prevention programs (i.e, deeper burial, increased surveillance interval)

How does Dynamic Risk support pipeline operators to address these updates?

Dynamic Risk supports various pipeline operators by providing technical expertise on pressure design and Class Location assessments per CSA requirements. Our team of experts is prepared for the upcoming changes and will continue to provide guidance to best support pipeline operators.

Our software application, IRAS ComplianceAuditor will provide a systematic way of incorporating all changes associated with the upcoming safety class and alternative pressure design calculations. It will simplify otherwise complex calculations such as determining population density along a sliding assessment area.

Figure 1: Illustration of population density calculation:

Safety Class CSA-Z662

About the Author:

Han Wu, P.Eng., PMP

Han Headshot formatted for WordPress

As Manager of Upstream Services and Analytics, Han manages a team of upstream asset integrity professionals for Dynamic Risk. With over 12 years of project management and pipeline integrity experience, Han is a Subject Matter Expert (SME) on pipeline risk assessments, in-line inspections, corrosion mitigation and integrity data management. He is also experienced with conducting integrity program reviews directly with field operations and has been directly involved with many pipeline integrity projects including conducting pipeline risk assessments, establishing pipeline system connectivity and implementing integrity data management solutions. Han is a professional engineer registered with APEGA (Association of Professional Engineers and Geoscientists of Alberta) and a member of the National Association of Corrosion Engineers (NACE).