Section 500.290  Purity of Gas

a)         Hydrogen Sulphide.  Manufactured gas and any mixtures of manufactured and natural gas distributed in this State shall not contain more than one grain of hydrogen sulphide per 100 cubic feet.  Any test approved by the Commission may be used for the determination of hydrogen sulphide.  This purity requirement will be considered as satisfied if a strip of white filter paper, recently moistened with a solution of 100 grains of lead acetate in 100 cubic centimeters of water, be exposed to the gas for one and one-half minutes in an apparatus previously purged, through which the gas is flowing at the rate of approximately five cubic feet per hour, the gas not impinging directly from a jet upon the test paper, and after this exposure the test paper be found not distinctly darker than a second paper freshly moistened with the solution and not exposed to the gas.  Test papers shall be kept for one year by a safe and secure method, and shall be available to the Commission if and when desired in that period.

b)         Total Sulphur.  Manufactured gas or any mixture of manufactured and natural gas distributed in this State shall not contain more than 30 grains of total sulphur per 100 cubic feet.

c)         Tests of Gas Purity.

1)         Each utility supplying manufactured gas or a mixture of manufactured and natural gas shall, for the purposes of record, daily test the gas leaving its holders for the presence of hydrogen sulphide in the manner specified.

2)         Each utility supplying manufactured gas or a mixture of manufactured and natural gas whose sales exceed fifty million cubic feet of gas per year shall provide and maintain such approved apparatus and facilities as are necessary for the determination of total sulphur; and each such utility shall at least once a week determine and put on record the amount of total sulphur in the gas distributed by it.