A clamp for coupling mating radially projecting flanges, each flange having a tapered outer face. The clamp includes at least a pair of component halves. Each half includes a generally U-shaped cross-sectional profile having a base portion and two opposing side limbs projecting from the base portion defining a recess intermediate the side limbs for receiving the mating flanges and a bolt and a lug for fastening the component halves together. Each side limb has a contact face for abutting a tapered face of a flange and a non-contact face. The base portion has a non-contact face. The contact faces of the side limbs are remote from the non-contact face of the base portion.