Plumbness Test for Storage Tanks Shell

sarmad

API650 gives the total out-of-plumbness and the out-of-plumbness for each shell course. What exactly is your difficulty at higher elevations?

i need another tool to chek the readings ,

using the plumb for the third course and over is not useful because of the wind , is there another tool

This is the type of thing to which Tornado refers - good suggestion.

A laser level/plumb bob might work for you.

thanks ,

thats what i need can you help me to buy it if you know any supplier,

regards

A simple laser pointer will work.Make certain it is mounted squarely to the tank or the base and is plumb.Then turn it on and measure to the mark(dot) from the drum at any point.Use a green laser it is easier to see than red.The measurement from the tank to the laser has to be precise, and the laser must be plumb.Use a machinist's level( 1/8 inch per 500 feet).This should give good accuracy.Turn it off when not is use to extend battery life.

You may want to check out Ebay or do a Google search for new or used laser levels....

Yes of course, the tool is called a string and a plumb bob. Simply measure the distance from said string to the surface of said tank a various locations, Not only can you determine just how much said tank may be out of vertical, you can determine if the walls of said tank are true.

TMF

Hello, I did not have time to read all posts but I am posting this with hopes I am not repeating another's post.

My suggestion to you is to take a 5 gallon bucket and fill with about 1/2 full of water and position it so that the plumb bob point is about 2-3" or 1/2 way down n the water. The bucket will keep the wind from having an effect on the plumb bob and the water will add stably to help keep the small movements of the string. Also if you use a small piano wire instead of string to suspend the plum bob it will help stabilize the whole thing. I have used a plumb bob, level and water level to set boiler components for many years and this method will work very good in a windy situation but it also helps with no wind too and it is very accurate as well. Also do not mess with trying to use the small plumb bobs for anything over 10-15' tall. I suggest a 5 pound or heavier plumb bob made from brass or steel when using piano wire instead of string. I have used the piano string and bucket of water technique for up to 250' elevations and get very accurate readings. I usually paint the bucket bright safety red and set something heavy in the bottom of the bucket like several steel plates to add a little weight so it will not be easily moved off target. Hope this helps.

Skyscrapers have been set using a 40 lb plumb bob and this method.

Good Answer, Pipewelder!

And the water level was used by the builders of the pyramids (I also used it to lay out my house foundations,etc).

To tell the truth you could just get a 6 foot level and check the thing in 2 or 3 places and pretty much know if it is within probably a 32nd" and do this in a hurricane and not effect the accuracy very much if any. Laser levels are great and I own several myself but I think they may be overkill for this purpose The fact that most anyone can read a 6 ft level but some employees may not know how to correctly set up and read a laser level I think the simple way would be best.

I guess I am somewhat old school in that I learned to set elevations with a plumb bob, tape measurer, 6 foot level, and a water level. I can still remember the very first time I used a water level to set water wall elevations on a large recovery boiler I was working on. I immediately realized here is a tool that could eliminate so many problems that were commonly seen when doing work where having correct elevations were critical. The thing that impressed me the most was how easy it was to get around obstacles and layout or check elevations with a water level and know it was 100% correct.

For some reason pipe fitters seemed to reject using the water level and they picked at me when I got the mine out at first. Usually after a day or so of watching me use it they would start to borrow mine so much that I would have to build another one in order to have one to use. The one thing I have hardly no use for is using a string line and level to project or transfer elevations. I used the string line and level when I was just learning to fit pipe and no matter how tight I would pull it it just would not be accurate enough to be able to fit pipe by. I used one once on a 6" s/s pipe line to transfer the elevation about 100 ft down a pipe rack and made the mistake of figuring a couple of offsets from the measurements I had taken from the line. Well I ended up doing that job twice before it was over and that pretty much ended my use of a string line and level

I too, followed the same learning curve with string levels.A water level is cheap, easy to make, and no big deal if it gets lost.And it is dead accurate no matter the distance or obstacles.Lasers only work in a straight line, then you have to transfer that mark, introducing another possible error point.

I always added a little color to the water to make it easier to see.

For true hair splitting precision, one must learn to look at the miniscus, not the point where the water adheres to the tube.There will be a slight difference, which in most cases does not matter, but if you really want to be as close to perfect as possible,use the miniscus.If you begin to lower the tube, after reaching stability, you will see the surface become convex.If you raise the tube, you will see it become concave.The center of the water column is the correct point in either case.Just a little bit of info I picked up using manometers for instrument calibration.When you are calibrating in 1/10 of an inch water column full scale, a little goes a long ways.

Beyond that resolution an inclined monometer is called for, with a calibration oil. This breaks the rise (or pressure) into very fine increments.

Still just a basic water level.

I am not finding any fault in your method, so don't get me wrong.Just knowing you are a person who seeks perfection with simplicity, I figured you would like to know.

IMHO

Hey EZstreet,

thanks for the info. I did know about the the point you made of where to actually look but i never knew it was called that I have to admit. The adding color to the line is a very good idea and I usually add red or green if I have it also if you add a small amount of antifreeze to the water it will add color and keep it from freezing up in the winter days.

Not long after I had learned about water levels I was tasked to use one to set the elevation on a lower water wall of a new boiler and I made a critical mistake that granted me the title of the job dumb-ass for about a week. I was working with an old boiler maker that I thought was very experienced with this type work . The boss brought us a water level up to use to set the elevation of the wall which was rigged and supported by 10, 6 ton come a long hoists attached from the lower section of wall to the upper section of the wall.

I assumed this boiler maker guy knew what he was doing (he was very good at saying he did at least) and we strung out the water level from side to side with one of us on each end as normal. Well we never could get that thing to balance out if I raised my side to the mark his would either raise very little or go way to much and just could not get a level point on the wall to start from. It wasn't long till the boss came by and said what the hell are you two doing drinking the damn water?

It was at this point I hollered down to tell him the water level was not working and something was causing it to not read correctly. He immediately replied do you have the valves open? Light bulb in the ole head went off I knew I had to answer him and say nope but I really did not want to go there.

I had spotted the valves right off and made the comment that this is a really nice water level. Up until this point the only water level I had used just had a plug in each end. I knew to remove the plugs before using it because someone probably had told me to at some point prior. For some idiotic reason I had not linked the valve is a form of plug reasoning and totally looked like a dumb ass and was let know this routinely by every one from the project manager to laborers on the job until someone else made a mistake and stripped me of my title. Even the old boiler maker tried to rib me about the mistake but I quickly asked him why in all of his experience he also did not know that the valves should be opened before use and he stopped when he realized I could let him share the title.

Here is the way I make my water level.

A 1 gallon milk jug, with a 1/4 inch tube inserted down the hollow handle to hold it steady.I then fill the bottle about 3/4 full and add coloring.I put the jug in a place where it will not be moved.(very important).I then syphon the tube to get it going, and make sure all of the bubbles are out of the system by letting a little run out of the end.I then walk the end back up to the jug and measure the level from the deck where the jug is placed.Now, anywhere I go with the tube will be the exact same level as my reference point.Then I measure down to the desired finish point from this reference.Assume the level in the jug is 8 inches above your desired starting point.Mark your destination with the tube, and measure down 8 inches.Bingo! exact same level as the starting point.I usually keep the tubing, and throw away the jug unless I am doing another job nearby.I have also used a wooden dowel with the jug level marked on it, and stick the dowel on the unlevel machine part and adjust the legs till the level aligns with the mark.Don''t even need a ruler.

If you want to level a ceiling, set the jug on a ladder, mark your walls with this reference and measure up to the finished ceiling height. Just dont move the ladder.

Very handy for many situations.

Hope this helps expand your uses for a water level.

You do of course realise that the discussion is for a vertical surface?

you realize I was replying to the previous post, not the forum in general?

I don’t do the tanks, but I have checked stacks.

I use a 3 axis, self leveling green laser, and a transit.

you need to green laser, it’s more intense, so you can see it.