Except as provided in §B of this regulation, a person operating a batch type hot-dip galvanizing installation is prohibited from: Using ammonium chloride (sal ammoniac) in prefluxes and top fluxes except where it is contained in a prepackaged flux compound of which the ammonium chloride content does not exceed 69 percent; and Applying a flux to a galvanized end product (dusting). A person operating a batch-type hot dip galvanizing installation using an emission control device approved by the Department is exempt from the requirements of §A of this regulation if the visible emissions requirement in Regulation .04 of this chapter is met.