255.739 Pressure-limiting and -regulating stations: inspection and testing.

(a)Each pressure-limiting station, relief device (except rupture discs), and pressure-regulating station and its equipment must be subjected, at intervals not exceeding 15 months, but at least once each calendar year, to inspections and tests to determine that:#

(1)it is in good mechanical condition;#

(2)it is adequate from the standpoint of capacity and reliability of operation for the service in which it is employed;#

(3)except as provided in subdivision (b) of this section, it is set to function at the correct pressure consistent with the pressure limits of section 255.201(b) of this Part; and#

(4)it is properly installed and protected from dirt, liquids or other conditions that might prevent proper operation.#

(b)For steel pipelines whose MAOP is determined under section 255.619(c) of this Part, if the MAOP is 60 psi (414 kPa) gauge or more, the control or relief pressure limit is as follows:#

If the MAOP produces a hoop stress that is: | Then the pressure limit is: Greater than 72 percent of SMYS | MAOP plus 4 percent Unknown as a percentage of SMYS | A pressure that will prevent unsafe operation of the pipeline considering its operating and maintenance history and MAOP.#

(c)If during the annual or any other regulating station inspection, the inspector finds that the regulator is not adequately protected from dirt or liquids, or does not respond properly to performance tests, an internal inspection shall be conducted and parts thereof overhauled to the extent necessary.#

(d)The operating condition of all operating pressure regulator stations except field regulators shall be inspected at least once each month. Such inspection shall include proper tests for gas leaks. A test with a combustible gas indicating instrument shall be conducted in all operating regulator stations contained in vaults, pits or other enclosed below grade and any unventilated aboveground building areas.#

(e)All stations shall be inspected periodically for excessive vibration in control piping. All suspect configuration shall be corrected promptly.#

(f)All combustible gas alarm systems shall be inspected in accordance with the manufacturer's recommended instructions.#