Skeleton procedure for pressure vessel design

Duty ( fluid, steady operating temperature and pressure )

Capacity, and possibly limits for diameter and/or length

Size of branches

Life

Procedure

1. Select design pressure, say 5-10 % in excess of operating pressure
    
2. Select material - generally the cheapest most readily available steel (eg. AS1548-1-430) consistent with duty

   	Adopt a suitable corrosion allowance
   	Determine design stress, equation ( i)

3. Select class if choice exists (fluid) - generally opt for cheapest class 3 if possible

   	Determine longitudinal joint efficiency

4. Select circumferential weld type for head connection - butt or fillet
    
5. Select head shape and size from available range

   	Determine head calculation thickness, equation ( vii) or ( viii)
   	Determine vessel bore consistent with head and end joint

   	Check that diameter lies within specification limits
   	Check branch-to-shell bore limits

   	Determine calculation thickness of shell, equation ( 1)
   	Determine vessel length from capacity

   	Check that length lies within specification limits
   	Check that length/bore ratio is feasible, say between 1.5 and 6, though higher values may apply to heat exchangers
   	Check plate size availability and bending machine capacity

6. Select form, size and location of inspection openings
    
7. Select thickness of shell, heads and branches from available ranges consistent with calculation thicknesses and corrosion allowance

   Check that class limits are not violated

   	Determine compensation needs, if any

8. Select details of major welds
    
9. Select details of small bore pipe attachments, supports etc
    
10. Determine total cost of solution