In the design of a shell and tube heat exchanger, the corrosion allowance
A
Need not be provided for non-pressure parts like tie rods, spacers, baffles, supports etc
B
For carbon steel and cast iron pressure parts is 1.5 mm (except for tubes) and for severe conditions it is 3 mm
C
For internal cover and tube sheet is provided on both the sides
D
All of the above
Correct Answer: All of the above