Static Test for Water Tank

150' high ! It is about 45m and 15 storeys. is the tank well reinforced? Or is it 15' ?

Big Wheel,

Come back with more information--is this tank elevated on legs 150' above the ground? Your post leaves us unsure. In deciding how to answer your question, you will probably have to assume that the tank empties in a short interval of time from a split seam. Look at the topography of the terrain; your safe distance may be a couple hundred feet if you are on higher ground, but may be as far as 2 or more miles if you are in a valley downstream. A serious rupture can be like a dam breaking. A smaller hole near the bottom of the tank can still have a force of nearly 75 psi behind the stream of water.

Remember also, that moving water is much more forceful than moving air; that a stream only a few inches deep can knock you down and carry you away (either by its direct force or by eroding the surface you are on).

Best wishes--JMM

I agree with the above posts that more information is needed.

On another note - here is an interesting video/article regarding a recent tank failure (be sure to watch the video!!).

http://www.norfolk.com/2008/12/chesapeake-orders-fertilizer-tank-drained-over-faulty-welds

"what the safe approch distance"

Are you trying to blow it up? Use cerosine on joints and see if it leaks though.

It sounds pretty big.

It is a new storage tank at ground level. On the west side is a road that is about 4' higher in elevation , on the east there is a increse of maybe a foot higher in elevation, on the north side there is a pump building approx. twenty five (25') feet away on the same evevation, on the south side approx. one houndred (100') away there is a screening bldg. at the same elevation .

Keep 'em on the road and out of the pump building.

(but realistically - a catastrophic failure could even wash up over 4 feet. It seems you are in a tough spot)

Your tank is absolutely on a wrong spot. I wouldn't dare to risk it in an environment like that. Storage tanks are normally located away from buildings and in any case there should be a regulation about it.

Big Wheel,

Thanks for the response to the questions. Last fall I was on site when an elevated Liquid Oxygen tank was given a hydrostatic pressure test. It was on very heavy pillars about 10 feet above the ground and was about 60 feet in diameter and nearly 100 feet tall. It took the people at least a half day to fill the tank with water from a fire hydrant, and we were sent off site for the final few hours of the test. It was in an open industrial area at least a half-mile from the nearest residence. During most of the filling time, we were kept at least 30 feet from the tank.

The location you describe sounds like a more congested area, but also without steep slopes. I'd suggest you contact the local emergency response people and get any safety suggestions they may have. If there are homes or businesses within a potential flood plain, they may want some form of notification or precautionary steps (such as moving vehicles off streets). For a relatively gentle slope, the water would spread fairly uniformly initially.

I don't have the tools to do any calculations, but I would suggest a couple things to do:

• Assume a sudden rupture of one weld, such as a 10 foot long seam that opens up by 1 foot at the bottom of the tank when it is full. If you model this as a smooth-sided opening without sharp edges, the flow through it would be nearly equal to that in a 20" or 24" pipe. With a pressure drop across this opening of nearly the height of water in the tank, the flow rate can be calculated as a function of time.
• Flow of water in river channels, as a function of slope, can give you the estimate of the rate of spread of this water from the rupture point. This can give you the speed and depth of the oncoming wave.

My purely empirical guess is that a safe distance for a person on flat ground would be where the oncoming wave is no more than 10 inches deep with a speed no more than 5 feet per second. I suspect that this will be somewhere near 200 feet from the tank. I chose these two numbers, based on the speed of a person's walk and experience with waves in the ocean.

Let us know what you come up with, and what you do! --JMM

Storage tanks are normally wider than higher. Are you sure it is 150 feet in dia and 100 feet high?

Who built this tank at the described location to start with. If the bottom seams fail. I can very well imagine what would happen. A damn will break and there would be many law suits against your company.

To test you would have to fill up with water slowly and pay attention that seams are doing well. Each time you cross the seam, watch the seams for any leaks. This way you would have some control. It may take you some longer period of time but you would not open the gate to hell because it it breaks when full, whole hell would break lose.

Good Luck.

Nadeem

04082009

Like your rose and its color.

Blue roses are rare. I could not grow in my garden so I got on the paper although I tried many times. I had several varieties of different colors but somehow my green thumb could not afford to grow blue rose. I used different kinds of rose foods over several years of trials but to no avail. Now I am happy, I can see it in my computer.

You like it, you can take it and I will go for a new yellow rose of Texas.

Regards;

Nadeem