1. (a) For the purpose of determining the sulfur content in grains of sulfur per 100 cubic feet of natural gas, the owner or operator shall use one of the following test methods:

   1. (1) ASTM D 1072-06 (2017);
   2. (2) ASTM D 4084-07 (2017);
   3. (3) ASTM D 3246-15;
   4. (4) ASTM D 5504-12; or
   5. (5) ASTM D 6228-10;

2. (b) For the purpose of determining the sulfur content in grains of sulfur per 100 cubic feet of LP gas, the owner or operator shall use one of the following test methods:

   1. (1) ASTM D 2420-13; or
   2. (2) ASTM D 2784-11.

Source. #7788, eff 10-31-02; ss by #9802, eff 10-31-10; ss by #12762, eff 5-1-19