132.110—Piping.
(a)
Except as provided for liftboats by § 134.180 of this subchapter, each fitting, flange, valve, and run of piping must meet the applicable requirements of part 128 of this subchapter. Piping must be—
(2)
At least extra-heavy schedule; or
(3)
Of a suitable corrosion-resistant material.
(b)
Each distribution cut-off valve must be marked in compliance with § 131.820 of this subchapter.