(a) This chapter does not apply to an agreement that provides for indemnity if the parties agree in writing that the indemnity obligation will be supported by liability insurance coverage to be furnished by the indemnitor subject to the limitations specified in Subsection (b) or (c).
(b) With respect to a mutual indemnity obligation, the indemnity obligation is limited to the extent of the coverage and dollar limits of insurance or qualified self-insurance each party as indemnitor has agreed to obtain for the benefit of the other party as indemnitee.
(c) With respect to a unilateral indemnity obligation, the amount of insurance required may not exceed $500,000.