Dip saturators have been installed for most new asphalt roofing line installations
in recent years, and this trend is expected to continue. Recent asphalt blowing still installations
have been almost exclusively of the vertical type because of the higher efficiency and lower
emissions. Vertical stills occupy less space and require no heating during oxidizing (if the
temperature of the incoming flux is above 400(F [204(C]). Vertical stills are expected to be
used in new installations equipped with stills and in most retrofit situations (U.S. EPA, 1980).