All site plan approvals shall expire and terminate three hundred sixty-five (365) days after the date of Council approval unless a building permit has been issued for the construction provided for in the site plan. The Commission and Council for reasons related to the Zoning Ordinance, the City Comprehensive Plan or for reasons of general City health and welfare may set an expiration and termination date at one hundred eighty (180) days after the date of Council approval unless a building permit has been issued for the construction provided for in the site plan. The Council may upon written request by the developer, extend the time for issuance of a building permit for sixty (60) days in addition to the termination date. In the event the building permit for construction provided for in a site plan expires or is canceled, then such site plan approval shall become null and void.