Hi Jeffrey,
For Canada, the Professional Practice Guidelines for each province will provide guidance on how long to retain drawings (APEGA in Alberta and EGBC in BC are the two I'm familiar with). There are also requirements for the party responsible for executing the Project (Engineer of Record) to retain historical records in the event there is litigation. From an Operations perspective, there are requirements to retain the stamped IFC and latest As-Built drawings (drawing type specific). For Alberta and BC, the respective Oil and Gas regulatory bodies provide these guidelines.
Hope that helps and sorry for the extremely delayed response.
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Carol Foster
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