For a cylindrical vessel of moderate height, the weld joint efficiency for joints parallel to the cylindrical axis is given as 1.0; while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylindrical vessel, what value of weld joint efficiency should be used ?

Related Mcqs:

1. For a cylindrical internally pressurised vessel, which of the following closure types would withstand highest pressure, if each closure is of the same material and thickness ?

   A. Hemispherical
   B. Ellipsoidal (2 : 1)
   C. Conical
   D. Flat plate

2. A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending upto double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design____________________?

   A. Only if the opening is on spherical vessel
   B. Only if the opening is on a vertical cylindrical vessel
   C. Only if the opening is on a horizontal cylindrical vessel
   D. Irrespective of the shape of the vessel

3. Normally, the plate thickness of the bottoms and roofs of vertically cylindrical storage vessels as compared to that of the cylindrical shell is____________?

   A. More
   B. Less
   C. Same
   D. More or less depending upon the pressure & temperature inside the vessel and the nature of
   the fluid contained therein

4. A cylindrical pressure vessel of volume 6 πm3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to________________?

   A. 5 mm
   B. 6 mm
   C. 8 mm
   D. 10 mm

5. For a cylindrical shell, (subject to the thickness of uppermost course being more than the minimum for dia of the tank in question), the thickness of the courses of shell_________________?

   A. Decreases upwards
   B. Increases upwards
   C. Remains same throughout
   D. May decrease or increase upwards depending upon whether vacuum or positive pressure
   would be maintained inside the shell

6. The wall thickness of thin cylindrical shell with hemispherical ends is ______________ that of the spherical ends?

   A. Equal to
   B. More than
   C. Less than
   D. Either B. or C.; depends on maximum permissible internal pressure

7. In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of ________________ mm?

   A. 3-5
   B. 5-11
   C. 8-15
   D. 12-18

8. A pressure vessel is said to be made of ‘thick’ shell, if the ratio of its diameter to wall thickness is_______________?

   A. < 10
   B. > 10
   C. > 20
   D. < 20

9. The ends of a cylindrical vessel can be closed by a head, which can be one of the four shapes. For the same thickness, choose the one which can withstand the highest pressure ?

   A. Flat plate
   B. Hemispherical
   C. Torispherical
   D. Ellipsoidal

10. In case of plain carbon steel, butt welded joints are used for shell plate thickness ≤ _____________ cms?

    A. 1.2
    B. 0.5
    C. 3.8
    D. 6.8