Double walled tanks with internal containment chambers

1. An above-ground storage tank comprising:

(a) a tank roof, a tank floor, a primary tank and a secondary tank, which together define a tank interstitial space therebetween;

(b) a containment chamber formed by a primary chamber wall and a secondary chamber wall, which together define a chamber interstitial space therebetween, and an exterior door assembly;

(c) wherein the primary tank, the primary chamber wall and the tank floor together define a tank interior volume

(c) at least one pipe and valve assembly wherein the pipe originates in the tank interior volume and the valve is disposed within the chamber;

(d) wherein the at least one pipe and valve assembly does not pass through the primary tank or the primary chamber wall in a non-freeboard zone.

2. The tank of claim 1 , wherein the at least one pipe and valve assembly passes into the chamber without passing through the primary tank at all, or passes through the primary tank in a freeboard zone and into the containment chamber from the tank interstitial space, or passes through the primary and secondary tank in a freeboard zone and into the chamber through the exterior door assembly.

3. The tank of claim 1 wherein the tank roof comprises an access hatch.

4. The tank of claim 1 wherein the at least one pipe and valve assembly comprises a one or more of a tank inlet pipe and valve, a tank suckout pipe and valve, or a tank overflow pipe and high level shut down valve.

5. The tank of claim 1 wherein the tank interstitial space and the chamber interstitial space are contiguous or connected.

6. The tank of claim 4 further comprising an interstitial connect disposed within the chamber, providing a fluid connection between the tank interstitial space or the chamber interstitial space, or both, and the high level shut down valve.

7. The tank of claim 6 wherein the interstitial connect is transparent or translucent to provide visual confirmation of the presence of absence of fluid in the interstitial connect.

8. The tank of claim 4 further comprising a siphon break connected to the suck out pipe, and a siphon valve disposed within the chamber.

9. The tank of claim 2 wherein the tank roof comprises an access hatch.

10. The tank of claim 2 wherein the at least one pipe and valve assembly comprises a one or more of a tank inlet pipe and valve, a tank suckout pipe and valve, or a tank overflow pipe and high level shut down valve.

11. The tank of claim 10 further comprising an interstitial connect disposed within the chamber, providing a fluid connection between the tank interstitial space or the chamber interstitial space, or both, and the high level shut down valve.

12. The tank of claim 11 wherein the interstitial connect is transparent or translucent to provide visual confirmation of the presence of absence of fluid in the interstitial connect.

13. The tank of claim 10 further comprising a siphon break connected to the suck out pipe, and a siphon valve disposed within the chamber.