Abstract: A frangible, circumferentially contractible clamp operated by a band constricting actuator for securing a pair of flange end pipe members in aligned end-to-end relation. The clamp includes a band consisting of retainer halves which are fastened together by frangible fasteners to form an envelope adapted to embrace and secure the aligned flanges together upon tightening of the actuator. Upon the associated pipes being subjected to exceptional tensile or bending forces, the fasteners will fracture permitting the retainer halves to separate to allow the flanges to separate and prevent the pipes from being damaged.