CTS Internal floating roofs The past atmospheric storage tanks have contributed significantly to emissions of volatile hydrocarbons (VOC’s). In recent years the economic aspects and environmental impact being the result of these emissions have gained more and more interest several products were developed to reduce emissions. At the basis of these developments was the internal floating roof. By covering major part of the liquid surface and through an effective seal the emission reduction by installing an internal floating roof is in can be up to 98%.