It's the relief vent from various safety valves and reaches the seal drum through a KO drum. We are planning to use cold water as sealing liquid. Max operating temp of SS seal drum is 113 Deg C. You may call it vent gas seal drum . Cold vent may be a misnomer.
Thanks bimr for giving the advantages of geodesic dome roofs. I also hear that there is good hydrocarbon emission control in using these roofs compared to welded steel roofs. I am requied to use this roof on a 40 M Dia tank to be used to store diesel. How can you achieve hydrocarbon emission...