(1) Notwithstanding NFPA 59, the quality of 100 percent if practical but not less than 90 percent of the shop and field welds in all piping two inches in nominal diameter or greater carrying LPG, flammable liquids, or flammable gas shall be nondestructively tested. Welds must meet requirements of API Standard 1104 (as described in section 10.3 of this Title) except for subsection 9.3.11 for undercutting to the root bead. Such undercutting shall not exceed two inches in length, or one sixth of the length of the weld, whichever is smaller. Nondestructive inspection may consist of radiographic examination, magnetic particle testing or ultrasonic. Other methods of nondestructive inspection may be used with prior approval of the department.

(2) When pipe carrying LPG, flammable liquids, or flammable gas has a nominal diameter of less than two inches, or when the construction project involves such a limited number of welds that nondestructive inspection would be impractical and the pipe is intended to operate at 20 percent or less of the specified minimum yield strength, then paragraph (1) of this subdivision is not mandatory, provided the welding is inspected visually and approved by a person qualified to inspect welding.

(3) In addition to the nondestructive inspection requirements outlined in this subdivision, there shall be continual control of the quality of welding by qualified personnel.

(4) Each gas corporation constructing an LPG facility shall have written welding procedures and welder testing procedures for field welding conforming to API Standard 1104 (as described in section 10.3 of this Title). All welders employed to make welds shall be qualified under the welder testing procedure.

(1) Piping with a maximum operating pressure up to 100 PSIG shall be tested with a calibrated indicating or recording gauge that will indicate two PSIG increments or less, at 150 percent of the maximum operating pressure, or 90 PSIG, whichever is greater. The test must be conducted by maintaining the pressure at or above the test pressure for at least one hour after stabilization. The test medium shall be air, inert gas or water.

(2) Piping with a maximum operating pressure 100 PSIG and higher shall be tested with a calibrated recording pressure gauge that will indicate increments of five PSIG or less and shall be attached to the test section. The gauge must be calibrated hourly. Calibration is against a dead-weight tester, or equivalent device, attached to the test section. The test pressure shall be at least equal to 90 percent of SMYS or 1.5 times the maximum allowable operating pressure, whichever is less. The strength test must be conducted by maintaining the pressure at or above the test pressure for at least four hours after stabilization. The test medium shall be air, inert gas, or water unless the maximum operating pressure is in excess of 20 percent SMYS in which case the test medium must be water.

(3) Due consideration and care shall be observed due to effects of changes in ambient and test medium temperature in the case of above-ground or exposed piping.

(4) If a component other than pipe is the only item being replaced or added to a pipeline, a strength test after installation is not required, provided the manufacturer of the component certifies that: