Bolts in the flanged end of pressure vessel are usually pre-tensioned. Indicate which of the following statements in not true.
(a) Pre-tensioning helps to seal the pressure vessel
(b) Pre-tensioning increase the fatigue life of the bolts
(c) Pre-tensioning reduces the maximum tensile stress in the bolts
(d) Pre-tensioning helps to reduce the effect of pressure pulsations in the pressure vessels