Did You Know?

Welded steel tanks are inherently more resistant to earthquake damage than equivalent-capacity bolted tanks with the same dimensions.

On a bolted tank, every bolt is a potential point of weakness. Consequently, there have been more catastrophic failures of bolted tanks than welded tanks from seismic activity.

It is for this reason and the benefits listed below, that SCCI prefers welded over bolted steel tanks.

SCCI Newsletters

Tank Mixing System Tank Mixing Systems Placing the inlet and outlet nozzles of water storage reservoirs on opposing sides of the tank shell was for years considered to be the optimum arrangement to achieve good water blending.
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Tank Sampling Stations Tank Sampling Stations Testing the quality of the water within water storage reservoirs is increasingly becoming more important. The use of chloramines as a method of disinfection requires that the chlorine residuals in the water reservoir be checked on a far more frequent basis.
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Welded Tank Benefits

Welded Steel - Photo courtesy US Navy
  • A welded tank can be built in any size and capacity up to 20MG. Bolted tanks generally come in standard sizes, which are dictated by the manufacturer, not the customer.
  • For two tanks of equal capacity, the welded tank is made of thicker/heavier steel, adding years to its useful life.
  • Welded tanks can be easily and cost-effectively adapted for cathodic protection systems. This extends the useful life of the tank's steel and its coatings. Because bolted tanks are gasketed, expensive jumper connections must be used to bond together every stave of a bolted tank.
  • Welded steel tanks are easy to recoat. Bolted tanks have many inaccessible areas that are subject to corrosion and must be disassembled, recoated, regasketed, and then reassembled.
  • With proper maintenance, the useful life of a welded tank is between 75 and 100 years. The lifespan of a bolted tank is between 25 and 30 years. While true that a bolted tank can be less expensive initially, this cost advantage disappears over time. Bottom line: The cost benefit per year of useful service is lower for welded tanks.

Bolted Tank Benefits

Bolted Steel
  • Bolted tanks are made of smaller sections, which allows them to be erected more easily in locations where limited access prevents the use of the larger cranes required for welded tank installations.
  • Bolted tanks are typically erected more quickly than welded tanks. However, since this is a website for SCCI, it is important to point out that we have developed a project management system that enables to complete a welded tank as fast or faster than a bolted tank. Remember that the average time between order and delivery of a bolted tank to the site is six to eight weeks.

  • SCCI Tanks - Casting in Place