Mapeo de Conceptos ISO/IEC 31000 e ISO/IEC 27005

In the United States, the family of ASME Boiler and Pressure Vessel codes, ASME B&PV, governs the design and construction of pressure vessels. The term pressure vessel refers to vessels operating at or above 15 psig, one atmosphere above the atmospheric pressure, or subject to external pressure. In addition to design and construction, the ASME B&PV codes also address material specifications and properties (ASME B&PV II), examination and leak testing techniques (ASME B&PV V), and maintenance and repair (ASME B&PV VI, VII, XI). Components designed and fabricated according to the ASME B&PV Code are stamped to indicate compliance. Following is a partial description of scope of the ASME Boiler & Pressure Vessel Code sections.

The ASME B&PV Code, Section I “Power Boilers”, applies to boilers in which steam or other vapor is generated at a pressure of more than 15 psig; high-temperature water boilers intended for operation at pressures exceeding 160 psig and/or temperatures exceeding 250°F. Components that comply with ASME B&PV Section I are stamped S=boiler, PP=pressure piping, E=electric boilers, M=miniature boilers, V=boiler safety valve.

The ASME B&PV Code, Section II “Materials” compiles the material specifications and material properties for materials used in the construction of ASME components. If a material is listed in ASME Section II, its ASTM specification number is preceded by the letter “S”. For example the designation SA106 applies to an ASTM A106 pipe material

“listed” in ASME Section II, permitted for use in the construction of ASME boilers and pressure vessels.

The ASME B&PV Code, Section III Division 1 applies to safety related components of nuclear power plants: vessels, piping, tanks, pumps and valves. The applicable stamps are: N for vessels, NP for piping, and NPT for components. The non-nuclear piping, or “balance of plant piping” is typically designed and fabricated to ASME B31.1. Piping systems in earlier nuclear power plants, licensed before 1971, are designed and constructed to ASME B31.1 or B31.7. ASME III Division 2 applies to the containment building of a nuclear power plant, and Division 3 applies to shipping containers for nuclear materials.

The ASME B&PV Code, Section IV Heating Boilers applies to hot water supply boilers, with the following services: steam boilers for operation at pressures not exceeding 15 psi; hot water heating boilers and hot water supply boilers for operating at pressures not exceeding 160 psi or temperatures not exceeding 250°F. Water heaters are exempted when their heat input is less than 200,000 But/hr, and their water temperature is less than 210°F, and their water capacity is less than 120 gal.

The ASME B&PV Code, Section V addresses the various techniques for non- destructive examinations (NDE) and testing (NDT), such as visual examinations, liquid penetrant testing, magnetic particles testing, radiography, ultrasonic inspections, pressure testing (hydrostatic or pneumatic), and leak testing.

The ASME B&PV Code, Section VI contains the “Recommended Rules for the Care and Operation of Heating Boilers”, while Section VII contains the “Recommended Guidelines for the Care of Power Boilers”.

The ASME B&PV Code, Section VIII “Pressure Vessels” addresses the design and fabrication of “unfired” pressure vessels (as opposed to “fired” boilers). These vessels are stamped “U” to signify “unfired”. The following classes of vessels are exempted from the scope of Section VIII Division 1: those within the scope of other sections (for example a Section X fiberglass vessel); fired process tubular heaters; pressure containers which are part of components of rotating or reciprocating mechanical devices (for example pump or compressor casings); piping systems, pipelines, and their components (for example a valve body). Also excluded from the scope of Section VIII are vessels for containing water under pressure, up to 300 psi, 210°F, and 200,000 Btu/hr, or 120 gal; vessels having an internal or external operating pressure not exceeding 15 psi, with no limitation on size; vessels having an inside diameter, width, height, or cross section diagonal not exceeding 6 in., with no limitation on length of vessel or pressure; and pressure vessels for human occupancy.

Division 2 of ASME VIII addresses the design and construction of unfired pressure vessels, but it relies on more detailed analyses and more fabrication constraints than Division 1, while allowing a lower safety factor. Division 3 of ASME VIII addresses thick vessels for high-pressure service. The applicable stamps for ASME B&PV Code Section VIII are: U=Div.1 pressure vessel, U2=Div.2 pressure vessel, U3=Div.3, UM=miniature vessel and UV=safety valves

The ASME B&PV Code, Section IX addresses “Welding and Brazing Qualification”, including welder and weld procedure qualification.

The ASME B&PV Code, Section X addresses the design and fabrication of fiber reinforced pressure vessels for general service. It sets minimum requirements for the

materials of fabrication; test procedures for mechanical properties of laminates, and design rules.

The ASME B&PV Code, Section XI “Rules for In-service Inspection of Nuclear Power Plants” applies to periodic inspections of nuclear power plant components as well as to the evaluation of degraded conditions, and their repair.

The ASME B&PV Code, Section XII is a recent document that covers the design and fabrication of transport pressure vessels.

An ASME Post Construction Code is under development that will include rules and guidance for inspection planning of pressure equipment, methods for flaw assessment, and techniques for repair and testing of pressure equipment.