THE SPIRAL DUCT MANUFACTURERS ASSOCIATION (SPIDA) was formed to promote the use of round duct, spiral duct (spiral pipe) and flat oval duct by informing the public of its advantages, supporting testing and research of round duct and spiral pipe, and providing manufacturers with specialized information necessary to the efficient operation of the business of the members. SPIDA's membership is composed of 90 member companies (and growing) engaged in the fabrication of round duct, spiral duct, flat oval duct, round duct fittings, and related items within the North American Continent.