Proceedings pending and rights and liabilities existing, acquired or incurred under existing construction regulations as long as they remain in effect are saved. The proceedings may be consummated according to the law in force when the proceedings were commenced. Neither this act nor the code shall be construed to alter, affect or abate a pending prosecution, or prevent prosecution hereafter instituted under such repealed construction regulations for offenses committed as long as the construction regulations remain in effect. Prosecutions instituted after the repeal of existing construction regulations for offenses committed before the effective date of the repeal may be continued or instituted in accordance with construction regulations in effect at the time of the commission of the offenses.