Alberta Common Ground Alliance (ABCGA) has come out with a new Best Practices for Locate Expiry.
Starting May 1, 2018, the lifespan of a locate ticket is extended to 30 days for most buried utilities in Alberta. Previously, locate tickets were only valid for 14 days, but could be extended to 30 days as long as certain conditions were met. Now locate tickets are valid for the full 30 days from the date they are issued (unless otherwise stated on the locate ticket).
This link outlines an extended expiry from 14 days to 30 days.