There shall be permitted, as a conditional use in all zone districts in the Township of Greenwich and upon prior approval thereof by the Land Use Board pursuant to N.J.S.A. 40:55D-67, emergency warning signal device systems (either individual units or chains or groups of units interconnected) the purpose of which is to provide early notification and warning to 100% of the threatened population of an actual or imminent risk to the public health and safety on account of any natural or man-made disaster or risk.