Rosart, JW 2010, 'Advantages of bolted tank construction for paste thickeners', in R Jewell & AB Fourie (eds), Proceedings of the Thirteenth International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 403-410, https://doi.org/10.36487/ACG_rep/1063_35_Rosart
For liquid containment tanks there are many benefits in using bolted joint construction rather than site
welding. Some of these include faster assembly time, better quality surface treatments, lower site costs from
reduced personnel and equipment, and the ability to easily move the tank to a different location. These
factors make bolted tank construction attractive to many industries. However, in thickening applications the
vast majority of tanks are site welded.
There are two key reasons why thickener users do not consider bolted tank construction more often:
• a higher capital cost for the thickener due to the significant number of bolts, flanges and associated
• uncertainty about the design of a safe and reliable bolted joint, especially for larger tanks.
Both of these considerations are important and should be evaluated carefully. Often, the higher initial
capital cost will translate into total project savings by replacing hundreds of metres of site welds and
painting with simple bolt tightening and torque inspection. For a typical welded thickener installation of
12 weeks it is common for an equivalent bolted design to take four to six weeks with less manpower.
Confidence in joint design comes down to good engineering, testing and field experience. If all three of these
conditions are met then the risk of leaking joints is minimal.
This paper presents some comparisons of bolted and welded tank designs for paste thickeners and evaluates
the total cost, time and risk considerations for each. Some examples of successful bolted thickener
installations are shown.
ANSI/API Specification 12B (2008) Specification for Bolted Tanks for Storage of Production Liquids, 15th Edition,
American Petroleum Institute, Washington D.C., USA.
API Standard 650 (2009) Welded Steel Tanks for Oil Storage, 11th Edition, Addendum 2, American Petroleum
Institute, Washington D.C., USA.