ASME SECVIII DIVI U-1

(d) The rules of ASME SECVIII DIVI have been formulated on the basis of design principles and construction practices applicable to vessels designed for pressures not exceeding 3,000 psi (20 MPa).

(e) In relation to the geometry of pressure containing parts, the scope of ASME SECVIII DIVI shall include the following:

(-a) the welding end connection for the first circumferential

joint for welded connections [see UW-13(h)];

(-b) the first threaded joint for screwed connections;

(-c) the face of the first flange for bolted, flanged connections;

(-d) the first sealing surface for proprietary connections or fittings;

 

  • where nonpressure parts are welded directly to either the internal or external pressure retaining surface of a pressure vessel, this scope shall include the design, fabrication, testing, and material requirements established for nonpressure part attachments by the applicable paragraphs of ASME SECVIII DIVI.
  • pressure retaining covers for vessel openings, such as manhole or handhole covers, and bolted covers with their attaching bolting and nuts;
  • the first sealing surface for proprietary fittings or components for which rules are not provided by ASME SECVIII DIVI, such as gages, instruments, and nonmetallic components.

(f) The scope of the Division includes provisions for pressure relief devices necessary to satisfy the requirements of UG-125 through UG-137 and Mandatory Appendix11.

(g) Vessels That Generate Steam

  • Unfired steam boilers shall be constructed in accordance with the rules of Section I or ASME SECVIII DIVI [see UG-120(f), UG-125(b), and UW-2(c)].
  • The following pressure vessels in which steam is generated shall not be considered as unfired steam boilers, and shall be constructed in accordance with the rules of ASME SECVIII DIVI:

(-a) vessels known as evaporators or heat exchangers;

(-b) vessels in which steam is generated by the use of heat resulting from operation of a processing system containing a number of pressure vessels such as used in the manufacture of chemical and petroleum products;

(-c) vessels in which steam is generated but not withdrawn for external use.

(h) Pressure vessels or parts subject to direct firing from the combustion of fuel (solid, liquid, or gaseous), which are not within the scope of Sections I, III, or IV may be constructed in accordance with the rules of ASME SECVIII DIVI [see UW-2(d)].

(i) Gas fired jacketed steam kettles with jacket operating pressures not exceeding 50 psi (345 kPa) may be constructed in accordance with the rules of ASME SECVIII DIVI (see Mandatory Appendix 19)

(j) Pressure vessels exclusive of those covered in (c), (g), (h), and (i) that are not required by the rules of ASME SECVIII DIVI to be fully radiographed, which are not provided with quick actuating closures (see UG-35), and that do not exceed the following volume and pressure limits may be exempted from inspection by Inspectors, as defined in UG-91, provided that they comply in all other respects with the requirements of ASME SECVIII DIVI:

  • 5 ft3 (0.14 m3) in volume and 250 psi (1.7 MPa) design pressure; or
  • 3 ft3 (0.08 m3) in volume and 350 psi (2.4 MPa)design pressure;
  • 11/2 ft3 (0.04 m3 )in volume and 600psi (4.1 MPa) design pressure.

In an assembly of vessels, the limitations in (1) through (3) above apply to each vessel and not the assembly as a whole. Straight line interpolation for intermediate volumes and design pressures is permitted. Vessels fabricated in accordance with this rule shall be marked with the UMSymbol in Figure UG-116 sketch (b) and with the data required in UG-116. Certificates of Compliance shall satisfy the requirements of UG-120(a).