Unless you pay for a combined pest and building inspection, a building inspector will not specifically look for signs of a termite infestation (although should mention the fact if obvious signs of termite activity are found).  If you want to make sure the building you wish to buy does not have a termite problem, you should pay for a specific pest inspection to be done, as this requires specialist equipment to listen for termite activity inside walls and cavities.  In this case, your sales contract clause would be ‘subject to a pest and building inspection.’