Rule 430. In addition to the requirements set forth in 49 C.F.R.§192.739, which is adopted by reference in R 460.20606, an operator of pipeline facilities used in the transportation of sour gas shall inspect all pressure limiting and pressure regulating devices at intervals of not more than 7 1/2 months, but not less than twice each calendar year.
Mich. Admin. Code R. 460.20430