The requirements of this chapter or amendment to this chapter shall not apply to any building, structure, or use proposed to be established pursuant to a valid building permit application pending as of the effective date of this chapter or amendment to this chapter, provided the permit application is approved and issued within 60 days after the effective date of this chapter or amendment to this chapter, and any development initiated pursuant to the issued permit commences within three months of the date of the issued permit. Failure to commence within the three month period shall subject the permit to the provisions of this chapter or amendment to this chapter.