Engineers' Guide to Pressure Equipment - Index of

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Engineers’ Guide to Pressure Equipment
probability of weld flaws and similar defects. Figure 3.1 shows a typical
‘generic’ representation of a pressure vessel. Basic vessel design is
concerned with internally pressurized, welded steel, unfired vessels
operating at room temperature and above, thereby avoiding the complexities
associated with:
• buckling due to external pressure and manufacturing inaccuracies;
• the effects of low temperatures on material properties.
A basic feature of all vessel design codes is the limitation placed on design
tensile stress, S, of the vessel material. A basic methodology is to define
acceptable design tensile stress as the minimum of:
(S y/A, S u/B, S yT/C, S crT/D)
where
S y = tensile yield strength (R e) at room temperature
S u = ultimate tensile strength (R m) at room temperature
S yT = tensile yield strength at design temperature
S crT = 100 000 h creep rupture strength at design temperature
A, B, C, and D are numerical factors that differ between design codes. Note
also how a variety of symbols are used – European and US codes use
different symbol sets, and both types are in common use. In general, US
practice is to represent stress by the symbol S (or F), while in Europe, the
use of σ is more common.
Fig. 3.1 A generic representation of a pressure vessel