Illinois Administrative Code › Title 41 - FIRE PROTECTION › Part 2120 - BOILER AND PRESSURE VESSEL SAFETY › Subpart B - CONSTRUCTION, INSTALLATION, INSPECTION, MAINTENANCE, AND USE › Section 2120.500 - Existing Installation of Pressure Vessels

Current through Register Vol. 48, No. 28, July 12, 2024
Maximum Allowable Working Pressure for Standard Pressure
				  Vessels. The maximum allowable working pressure for standard pressure vessels
				  shall be determined in accordance with the applicable provisions of the ASME
				  Code under which they were constructed and stamped.
a) Maximum Allowable Working Pressure for
				Nonstandard Pressure Vessels.
1) For Internal
				Pressure. The maximum allowable working pressure on the shell of a nonstandard
				pressure vessel shall be determined by the strength of the weakest course
				computed from the thickness of the plate, the tensile strength of the plate,
				the efficiency of the longitudinal joint, the inside diameter of the course and
				the factor of safety set by this Part.
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Where:
TS = ultimate tensile strength of shell plates, psi. When the
				  tensile strength of steel plate is not known, it shall be taken as 55,000 psi
				  for temperature not exceeding 650F.
t = minimum thickness of shell plate of weakest course,
				  inches.
E = efficiency of longitudinal joint, depending upon
				  construction. Use the following values:
For Fusion-Welded and Brazed Joints:
Single lap welded
				  ................................................ 40
Double lap
				  welded............................................... 60
Single butt
				  welded............................................... 60
Double butt
				  welded.............................................. 75
Forge
				  welded........................................................ 70
Brazed
				  steel.......................................................... 80
For riveted joints - calculate riveted joint efficiency in
				  accordance with rules given in Section I, Part PR, of the 1971 Edition ASME
				  Code.
R = inside radius for weakest course of shell, inches,
				  provided the thickness does not exceed 10 percent of the radius. If the
				  thickness if over 10 percent of the radius, the outer radius shall be
				  used.
FS = factor of safety permitted shall be a minimum of
				  5.0.
2) For External
				Pressure. The maximum allowable working pressure for cylindrical nonstandard
				pressure vessels subjected to external or collapsing pressure shall be
				determined by the Rules in Par. UG-27 and UG-28 of Section VIII of the ASME
				Code.
3) Factors of Safety. The
				minimum factor of safety may be increased when deemed necessary by the
				Inspector to assure the operation of the vessel within safe limits. The
				condition of the vessel and the particular service to which it is subject will
				be determining factors.
4) End
				Closures. The maximum allowable working pressure permitted for formed heads
				under pressure shall be determined by using the appropriate formulas from Par.
				UG-32, UG-33, or UG-35 of Section VIII, ASME Code and the tensile strength and
				factors of safety given above.