On loans secured by liens upon real property or leasehold interests therein, the buildings and other improvements located on the premises shall be kept insured against loss or damage from fire in an amount not less than the unpaid balance of the obligation or the insurable value of the property, whichever is the lesser. The fire insurance policy or policies shall be payable to the insurer, or a trustee for its benefit, and continued in force until the loan is repaid or satisfied. Such policy or policies shall be held by the insurer or the trustee, unless the Director of the Department of Consumer and Business Services has determined that a different method of protecting the insurers against loss is satisfactory and has given prior approval of such method to the insurer. [1967 c.359 § 254; 1969 c.336 § 10]