CHAPTER 9 PRE-ENGINEERED STORAGE TANKS

During World War II, steel tanks made possible many operations. During large operations, especially in forward areas, the need for rapid transport and appropriate storage facilities were of major importance. Steel tanks were used to store fuel, diesel oil, gasoline, and water to meet the demand for storage facilities. Ships and planes were supplied from secret tank farms at overseas bases, making possible many of the large invasions of the war in the Pacific.

This chapter will brief you on the procedures to follow in erecting bolted steel tanks including preparation of the foundation for a tank-

STEEL TANKS

Many types of tanks are available. Besides tanks that are constructed of standard mild steel sheets, tanks of galvanized steel sheets and of wrought iron may also be obtained. Tanks may be bolted, riveted, or welded. Bolted and riveted tanks have capacities of up to 10,000 barrels. Welded tanks may hold as many as 50,000 barrels.

Steelworkers are normally concerned with PREFABRICATED BOLTED TANKS. These tanks are composed of steel sheets of a size that is easily transported. Individual pieces are quite light. They can be assembled quickly in the field by crews of relatively untrained men so long as the man in charge understands the details of their construction. Once the tanks are assembled, they will last for 5 or 6 years or longer. A shipment includes all of the bolts, the nuts, the fittings, and the gasket material required for assembly. Drawings and assembly instructions also are provided.

Ten-thousand-barrel tanks are used to store fuel and diesel oil at overseas bases. One-thousand-barrel tanks are used for gasoline storage. Low 5,000-barrel tanks are seldom used for fuel storage where large operations are under way, but they may be used for storage of water. Since a barrel is equal to 42 gallons, you can see that a 10,000-barrel tank is capable of holding 420,000 gallons.

If desired, bolted steel tanks can be dismantled and re-erected at another location. You can obtain re-erection kits that contain new gasket material and extra nuts and bolts. In disassembling a tank, however, workers should make an effort to save all of the items of hardware that can be used again. When taking down a tank, avoid damage to any of the members because the number of re-erections of a tank depend largely upon the care taken during dismantling.

CAUTION Exercise care when handling plates to avoid bending, dropping, or otherwise damaging the steel. Bent plates will cause problems when the tank is erected, and when used, the result is usually a leaking tank.

TANK FOUNDATIONS

Considerable care should be taken in constructing the GRADE or finished foundation on which the tank is to be erected. Concrete foundations are ordinarily not necessary if the ground is reasonably hard. When the grade is properly prepared and perfectly level, the tank can be joined on an even surface, and, therefore, it is easier to fit up and erect the tank Also, with proper support, the completed tank will be less likely to leak.

Grading

The earth grade should be constructed approximately 1 foot greater in diameter than the diameter of the tank which is to occupy it. The earth must be well-tamped to a firm and smooth surface. Never fill the area for a tank foundation because erosion will, in time, result in a faulty foundation.

Foundation Construction

The tank foundation should be dry, level, and well-drained. A layer of clean gravel or sand on the grade is ideal for this purpose. Tar paper may be spread under the tank as a corrosion-resistant carpet.

When a layer of gravel or sand is used on a grade of firm earth, follow these steps:

1. Drive a peg in the exact center.