Where the duration of the use or building has been limited by action of the Zoning Hearing Board, Borough Council or provisions of this chapter, or any amendment thereto, the life of the zoning permit shall be equally limited. In the event that a variance has been granted or other action has been authorized by the Zoning Hearing Board, the applicant shall secure the necessary permits and commence the authorized action, construction or alteration within 180 days of the final action of the Zoning Hearing Board. The applicant may request, in writing, extensions of the one-hundred-eighty-day period stating the reasons for delay. Unless the Zoning Hearing Board finds such reasons for delay justifiable, it may refuse to extend the one-hundred-eighty-day period and may, after expiration of said one-hundred-eighty-day period, rescind or revoke the granted variance, authorization and permit. When it is suspected that the authorized construction or development will commence in phases over an extended period of time, the Zoning Hearing Board may establish a schedule for the procurement of permits in lieu of the one-hundred-eighty-day period specified hereinabove. Such permit issued shall become invalid if the authorized work is suspended or abandoned for a period of one year after the time of commencing work. Upon expiration or invalidation of the zoning permit, all other permits issued thereon shall become invalid.