Boiler and Pressure Vessel Definitions
ASME Code: The Boiler and Pressure Vessel Code of the American Society of Mechanical Engineers approved and adopted by the governing council of such.
Boiler: A closed vessel in which water is heated, steam is generated, steam is superheated, or any combination of them, under pressure or vacuum for use externally to itself by the direct application of heat. This shall include fired units for heating or vaporizing liquids other than water where these units are separate from processing systems and are complete within themselves.
Certificate of Inspection: An inspection, the report of which is used by the Chief Inspector (of Virginia) to decide whether of not a certificate as provided by 40.1-51.10 may be issued.
Factors of Safety: The minimum factor of safety shall in no case be less than 3.5 for vessels built on or after January 1, 1999.
Hydrostatic Pressure Test: The primary method used to test for leaks and assess the structural integrity of pressurized vessels. It is conducted by filling the pressure vessel with water and pressurizing it to test for strength and leaks. The test shall not exceed 1.25 times the maximum allowable working pressure, except as provided by the ASME Code.
Maximum Allowable Working Pressure (MAWP) for formed heads under pressure: The MAWP for formed heads under pressure shall be determined by using the appropriate formulas from Section VIII, Division 1, ASME Code and the tensile strength and factors of safety given in subdivisions 1 and 3 of the Boiler and Pressure Vessel Safety Act (16 VAC 25-50-380).
Maximum Allowable Working Pressure (MAWP) for non-standard pressure vessels: For internal pressure. The MAWP on the shell of a non-standard 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 weakest course and the factor set by the Boiler and Pressure Vessel Safety Act. For external pressure. The MAWP for cylindrial non-standard pressure vessels subjected to external or collapsing pressure shall be determined by the rules in Section VIII, DIvision 1, of the ASME Code.
Maximum Allowable Working Pressure (MAWP) for standard pressure vessels: As determined by the applicable provisions of the edition of the ASME or API-ASME code under which the standard pressure vessel was constructed and stamped. The MAWP shall not be increased to a greater pressure than shown on the manufacturer's nameplate stamping and data report.
Non-Standard Boiler or Pressure Vessel: A boiler or pressure vessel that does not bear the stamp of the Commonwealth of Virginia, the ASME stamp, or the National Board stamp, when applicable.
Pressure Relief Devices: Pressure relief devices are used to provide a means of venting excess pressure, which could rupture a boiler or pressure vessel. It is the last line of defense for safety. There are many types, such as a safety valve (typically used for steam or vapor service), relief valve (typically used for liquid service), safety relief valve (serves as both a safety valve and a relief valve), and rupture disk (a non-reclosing disk which is destroyed upon actuation).
Pressure Vessel: A vessel in which the pressure is obtained from an external source, or by the application of heat from an indirect source, or from a direct source, other than those boilers defined by the code.
PSIG:Pounds per square inch gauge.
Standard Boiler or Pressure Vessel: A boiler or pressure vessel that bears the stamp of the Commonwealth of Virginia, the ASME stamp, and the National Board stamp, when applicable.
Unfired Pressure Vessel:A vessel in which the pressure is obtained from an external source, or by the application of heat from an indirect source, or from a direct source, other than those vessels defined as "boiler".
Variance: Upon application pursuant to the provisions of subdivision (9) of 40.1-6, the Commissioner may allow variances from a specific regulation provided the applicant proves by clear and convincing evidence the boiler or pressure vessel meets substantially equivalent operating criteria and standards.