Pressure Vessels

PURPOSE: This rule is to address the design, construction, installation and operation of pressure vessels. (1) As used in this rule, the term “these rules” is intended to mean 11 CSR 40-2.010 through 11 CSR 40-2.065. (2) Pressure vessels installed or contracted for, prior to November 12, 1986. (A) The service life of any pressure vessel of standard construction shall be unlimited provided it meets the inspection requirement of 11 CSR 40-2.022. (B) The service life of any nonstandard pressure vessel shall be thirty (30) years. The thirty (30)-year life may be extended with the chief inspector’s approval and compliance with the following requirements: 1. The operating pressure cannot exceed the maximum allowable working pressure (MAWP). The pressure vessel MAWP shall be calculated in accordance with the American Society of Mechanical Engineers (ASME) Section VIII Code or to the requirements of the original code of construction. Objects manufactured to a standard other than the ASME Code shall be evaluated in accordance with the “state special” requirements of 11 CSR 40-2.064. The allowable stress shall be no greater than twenty-two percent (22%) of the tensile strength of the material. If the tensile strength is unknown, an allowable stress of twelve thousand (12,000) pounds per square inch (psi) shall be used. The joint efficiency shall be in accordance with the following for welded and brazed joints; A. Single lap weld = 0.4 B. Double lap weld = 0.5 C. Single butt weld = 0.6 D. Forge welded = 0.7 E. Brazed (steel) = 0.8 F. Seamless = 0.85 unless radiography of all butt welds is performed G. Seamless = 1.0 if radiography of butt welds is performed H. Riveted = use the appropriate ASME Code or the National Board Inspection Code (NBIC) rules. 2. The pressure vessel shall be tested every six (6) years at normal operating pressure not to exceed the MAWP of the pressure vessel. The pressure test shall be held for at least thirty (30) minutes and documented to the satisfaction of the inspector. An inspector need not witness the test. Any leaks shall be repaired prior to restoring the object to service. 3. All safety devices and controls required by the ASME Code and these rules shall be installed and operable. (3) Pressure vessels installed or contracted for after November 12, 1986. (A) New and second hand pressure vessels shall be designed, fabricated and installed in accordance with the ASME Code and these rules. (B) Reinstalled pressure vessels may be of standard or nonstandard construction and shall be installed in accordance with the requirements of the ASME Code and these rules. Approval of the chief inspector shall be obtained prior to reinstalling a nonstandard pressure vessel. (4) General Requirements for Pressure Vessels. (A) All pressure vessels shall be equipped with pressure relief devices in accordance with their code of construction. In cases where the original code of construction does not address pressure relief devices, such devices shall be installed in accordance with the most applicable ASME Code. (B) Each pressure vessel shall be safely supported. There shall be no excessive vibration in either the pressure vessel or the connecting piping. (C) Pressure vessels shall have adequate clearance on all sides and top to facilitate repair, maintenance and inspection. Manufacturer’s recommendations, when provided, shall be followed. (D) Code nameplates shall remain readily accessible at all times. Loose or missing nameplates shall be replaced or reattached as provided for in the National Board Inspection Code. (E) Rental pressure vessels used for temporary service shall meet all of the requirements of these rules. AUTHORITY: section 650.215, RSMo 2000.* Original rule filed May 12, 1986, effective Oct. 27, 1986. Amended: Filed Oct. 3, 1995, effective April 30, 1996. Rescinded: Filed March 10, 2003, effective Aug. 30, 2003. Readopted: Filed Sept. 25, 2002, effective May 30, 2003. *Original authority: 650.215, RSMo 1984, amended 1990, 1993, 1995.