Storage tank double containment

Glean Water Act. The Water QuaUty Act of 1987 and Clean Water Act of 1977 amended the Water Pollution Control Act of 1972, and are known collectively as the Clean Water Act (CWA). Their objective is to restore and maintain the integrity of U.S. waters. There are spill prevention, control, and containment requirements with which to comply. It requires replacement of older storage tanks or installation of double bottoms or seals. 

Dairy farms have bulk-storage tanks with their own refrigeration plants. These are usually made in the form of a double-skin, insulated tank, having the evaporator coils in the jacket, which also contains water. The refrigeration system runs throughout the 24 hours and... 

A double-wall AST of steel fulfills the same function as a diked AST with rain shield. Double-wall designs consist of a steel wrap over a horizontal or vertical steel storage tank. The steel wrap provides an intimate, secondary containment over the primary tank. One such design is the Steel Tank Institute s F921 standard, based upon... 

Secondary containment enclosures other than double-wall construction have been widely used to control vessel leaks. Bunkers built around underground storage tanks are common examples of this approach to preventing releases to the atmosphere and into the soil around the tank, to minimize potential for ground water contamination. Use of tank-high dikes with covers or roofs is another example of secondary containment that limits postrelease emissions. 

Deterrent countermeasures either discourage terrorists from considering your facility or stop attacks in progress. For example, pop-up bollards in roadways may be used to stop an intruding vehicle. Large earthen berms around storage tanks serve double duty to stop a vehicle and contain a chemical spill. Real or dummy video cameras can cause a terrorist to consider another target. 

Bulk phosgene is kept in underground storage tanks of double shell construction in some facilities [1488]. This provides containment in the event of a leak from the inner wall, and protection from mechanical damage to the outer wall. If the outer shell also develops a leak then the surrounding earth would prevent a large scale release of gas [1488]. 

Double-wall storage tank A double-wali storage tank has an inner wall to contain a liquid, an annulus. space usually filled w ith insulation, and an outer wall for. spill containment. 

The revised mle also states that all bulk storage container installations mnst provide a secondary means of containment for the entire capacity of the largest single container, with sufficient freeboard to contain precipitation, and that such contaimnent is sufficiently impervious to contain discharged oil. US EPA encourages the use of industry standards to comply with the rules. Many ovmers of shop-fabricated tanks have opted for double-wall tanks built to STI or UL standards as a means to comply with this requirement. 

Double-wall tanks are known in various designs. In the simplest version an inner tank designed for storage temperature and pressure is surrounded by a second tank. The annular space between the two walls is filled with insulation material, for example, Perlite. The main purpose of the outer shell is to contain and hold the insulation. Today s usual practice is to design the outer shell to the same standard as the inner shell. This so-called double-integrity tank concept provides an additional safety measure as the outer tank can hold the full content if the inner shell fails. 

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