(1) Plan review approval by the department is valid for two years and substantial and continuous construction must be initiated within 12 months of the date of approval.

(2) If substantial and continuous construction has not been initiated within 12 months from the date of the department's plan approval, the owner must obtain an extension in writing from the department. In no case shall an extension of the plan approval be granted for more than 18 months beyond the date of the original approval. The department is not required to approve a request for an extension of the plan approval.

(3) In any instance in which construction is not initiated within one year of plan approval or within the time granted for an extension, construction must cease and plans, specifications, and supporting documents, and appropriate fees must be resubmitted for another review.