Existing Pressure Vessels

(1) Maximum Allowable Working Pressure for Standard Pressure Vessels. The maximum allowable working pressure for standard vessels shall be determined in accordance with the applicable provisions of the ASME Code or the API-ASME Code. The maximum allowable working pressure shall not be increased to a greater pressure than shown on the manufacturer’s nameplate stamping and data report unless prior approval is obtained from the Chief Inspector or Chief Inspector’s Designee. (2) Maximum Allowable Working Pressure for Nonstandard Pressure Vessels. (a) The maximum allowable working pressure of a nonstandard pressure vessel shall be determined in accordance with ASME Code, Section VIII, Division 1, UG-27. (b) The minimum factor of safety shall in no case be less than five (5) for existing installations. The working pressure shall be decreased when deemed necessary by the inspector to insure the operation of the vessel and its particular service. (c) The maximum allowable working pressure permitted for formed heads under pressure shall be determined by using the appropriate formulas from ASME Code, Section VIII, Division 1, and the tensile strength and factors of safety given in this rule. BOILER INSPECTIONS CHAPTER 0800-03-03 (d) The maximum allowable working pressure for nonstandard pressure vessels subject to external pressure shall be determined in accordance with ASME Code, Section VIII, Division 1. (3) Inspection of Inaccessible Parts. If the inspector determines during an inspection that it may be necessary to remove the interior or exterior lining, covering, or brickwork to expose certain parts of the vessel not normally visible, the owner or user shall remove such material to permit a proper inspection and the remaining thickness. (4) Overpressure Protection. Each pressure vessel shall be provided with safety relief valves and controlling devices as necessary to protect against overpressure. These devices shall be so constructed, located and installed that they cannot be rendered inoperative. The relieving capacity of such pressure relief devices shall be adequate to prevent a rise in pressure in the vessel of no more than ten percent (10%) above the highest pressure to which any pressure relieving device is set. The opening pressure of the lowest set pressure relieving device shall be no greater than the maximum allowable working pressure of the vessel. Where an additional hazard is involved due to fire or other unexpected sources of external heat, the pressure relief devices shall meet the requirements of ASME Code, Section VIII, Division 1, Paragraph UG-125 or Division 2, Paragraph 9.2, whichever is applicable. (5) Repairs and Renewals of Fittings and Appliances. Whenever repairs are made to fittings and appliances or it becomes necessary to replace them, the work must comply with the requirements for new installations.