Section VIII Code

Until the arrival of uniform guidance, an advisable solution, apart from the use of valves without the joint in question ( bonnetless valves) or the systematic use of a sealing weld, is to adopt the value of the gasket tightening force suggested by the manufacturer, under the condition that it complies with the ASME (Section VIII) code for the stresses in the bolted joint. If this is not the case, the tightening force should be decreased until the specifications of the ASME code are met. 

ASME Section VIII Code for Unfired Pressure Vessels. 

REQUIRED DATA FOR AAATERIAL APPROVAL IN THE ASME SECTION VIII CODE... 

The 1983 ASME Section VIII Code, VUI-l, lists five nonferrous alloys for code construction aluminum, copper, nickel, titanium, and zirconium. These alloys are normally used in corrosive environment or elevated temperatures where ferrous alloys are unsuitable. Nonferrous alloys are nonmagnetic except for commercially pure nickel which is slightly magnetic. 

ASME Boiler and Pressure Vessel Code. The ASME Boiler and Pressure Vessel Code is pubhshed in 11 sections. Section VIII, which is concerned with rules for the design of unfired pressure vessels, was first pubhshed in 1925 and since 1968 it has been issued in two parts. Division 1 (147) and Division 2 (148), the latter being known as the Alternative Rules. 

Codes Standards approved the estabUshment of a Special Working Group for high pressure vessels under the ASME Subcommittee on Pressure Vessels (Section VIII). The main design criteria, which are likely to be incorporated in a new Division of Section VIII, have been set out (149). 

ASME Code Section VIII, Division 1 Most pressure vessels iisedin the process indiistiy in the United States are designed and constructed in accordance with Sec. TH, Division I (see Fig. 10-187). This division is divided into three subsections followed by appendixes. 

The inlet flange shall be of the weldneck type with raised face designed in accordance with ASME BPV Code Section VIII. The flange shall be axial entry with a surface finish of 150-250 micro inches. The gasket shall be of the spiral-wound metal type with a seating stress of 10,000 psi. 

The ASME code provides the basic requirements for over-pressure protection. Section I, Power Boilers, covers fired and unfired steam boilers. All other vessels including exchanger shells and similar pressure containing equipment fall under Section VIII, Pressure Vessels. API RP 520 and lesser API documents supplement the ASME code. These codes specify allowable accumulation, which is the difference between relieving pressure at which the valve reaches full rated flow and set pressure at which the valve starts to open. Accumulation is expressed as percentage of set pressure in Table 1. The articles by Rearick and Isqacs are used throughout this section. 

This figure conforms with the requirements of Section VIII of the ASME Boiler and Pressure Vessel Code. 

Section VIII, Division 1, Appendix M, of the ASME Code should be referred to for guidance on blowdown and pressure differentials. 

Section VIII, Division I Supierscript = Foouiote reference fuly I, 1989 Edition in Code Figure No., for this text. 

Reprinted with ASME permission. ASME Pressure Vessel Code, Section VIII, Division I, UG-127, 1989 Edition, pp. 86-88. 

Code, Section VIII, and are tested at capacity by the National Board of Boiler and Pressure Vessel Inspectors. This type of valve characteristically pops full open and remains open as long as the overpressure exists. 

In the United Kingdom all conventional pressure vessels for use in the chemical and allied industries will invariably be designed and fabricated according to the British Standard PD 5500 or the European Standard EN 13445 or an equivalent code such as the American Society of Mechanical Engineers code Section VIII (the ASME code). The codes and standards cover design, materials of construction, fabrication (manufacture and... 

Boiler and Pressure Vessel Code, Section II, Materials (Part A, Ferrous Material Specifications, and Part D, Properties ), Section ID, Rules for Construction of Nuclear Power Plant Components, and Section VIII, Pressure Vessels, Divisions 1 and 2. Code for Pressure Piping, ASME/ANSI B31.3, Chemical Plant and Petroleum Refinery Piping ... 

The limits described by these curves are based on experience with cast steel as well as annelaed and normalized steels at stress levels defined by Section VIII, Division I, of the ASME code. See 3.3 and 5.4 in text for additional information. 

Many users have reported satisfactory performance of annealed or normalized and tempered steels produced before 1969, as shown in Figure 1. These steels have been used for pressure-retaining equipment at design stress levels allowed by the 1969 or earlier editions of commonly-accepted codes (such codes include the ASME Code, Section VIII, Division 1 the standards of the American National Standards Institute and, for the lower-strength materials, those of Deutsche Industrie-Normen). However, pressure vessels in hydrogen service have also been constructed using the higher allowable stresses permitted in either Section VIII, Division 2, or modifications of Section III of the ASME Code. Quenched and tempered or normalized and tempered steels have normally... 

No incidents of decarburization or Assuring of pressure vessels built to the specifications of Section VIII, Division 2, of the ASME Code have been reported. None of the failure data in Figure 1 represent materials used at the higher allowable stresses. 

ASME, 2001. Boiler and Pressure Vessel Code, Section I, Power Boilers, and Section VIII, Pressure Vessels. American Society of Mechanical Engineers, New York. 

The ASME Boiler and Pressure Vessel Code, Section VIII, is the standard resource for the design, fabrication, installation, and testing of storage tanks and process vessels rated as pressure vessels (i.e., above 15-psig design). ASME B31.3 is a basic resource for process piping systems. 

IP-3.5 ASME BPV Code Section VIII, Division 1 References for Closures. 87... 

The design pressure shall not exceed 6,000 psi unless the material suitability is demonstrated by tests in hydrogen, such as per KD-10 of ASME BPV Code Section VIII, Division 3. 

Fabrication by welding of clad or lined piping components, and the inspection and testing of such components, shall be done in accordance with applicable provisions of the ASME BPV Code, Section VIII, Division 1, UCL-30 through UCL-52, or the provisions of Chapters IP-9 and IP-10, whichever are more stringent. 

To determine wall thickness and stiffening requirements for straight pipe under external pressure, the procedure outlined in ASME BPV Code Section VIII, Division 1, UG-28 through UG-30 shall be followed, using as the design length, L, the running centerline... 

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