I'll give you some of my limited knowledge of asphalt tank storage.. Commercial grade asphalt is typically stored in aboveground, vertical axis, flat bottomed tanks. Storage temperatures range from %7E140F to %7E180F. The tanks are insulated and ususally kept full if possible. Tank gauging has always been a problem with these tanks.... radar level detection systems have been suggested. Water is periodically drawn from the tank interior to mitigate internal corrosion. Corrosion is typically found in the interior roof area and sometimes on the exterior tank bottom (galvanic corrosion with the soil) Interesting links on asphalt tank corrosion and safety: http://www.pca.state.mn.us/publications/t-a2-08.pdf http://www.nacestore.com/nace/content/pubsonline/free/9907mpab.pdf http://www.steeltank.com/library/pubs/news-012004.pdf http://www.systems.endress.com/news/assets/Systemlinkmar_2003.pdf Do you work for a state agency and are trying to develop inspection guidelines ??? My opinion/ramblings only MJC

Final question, I don't understand exactly what you meant by: "Water is periodically drawn from the tank interior to mitigate internal corrosion." Is this a situation where water is removed from the tank interior? If so is this water the result of condensation from the atmosphere? Is the condensation a by-product of high relative humidity? Or is there something in the asphalt which is hydrophilic? Best Regards,