The National Union of Sheet Metal Workers and Braziers was formed in July 1920 by an amalgamation of a large number of local societies which had previously been associated in a looser federal structure in the National Amalgamated Sheet Metal Workers and Braziers. In July 1959 it merged with the National Society of Coppersmiths, Braziers and Metalworkers to form the National Union of Sheet Metal Workers and Coppersmiths. In April 1967 this amalgamated with the Heating and Domestic Engineers' Union to form the National Union of Sheet Metal Workers, Coppersmiths, Heating and Domestic Engineers. Finally, in 1983 this merged with the Amalgamated Union of Engineering Workers (Technical, Administrative and Supervisory Section) (TASS).
Reference: Ted Brake, Men of Good Character: A history of the National Union of Sheet Metal Workers, Coppersmiths, Heating and Domestic Engineers (Lawrence and Wishart: London, 1985).
From the guide to the Papers of the National Union of Sheet Metal Workers, Coppersmiths, Heating and Domestic Engineers and predecessors, 1920-1983, (Modern Records Centre, University of Warwick Library)