Locating nozzles on existing tanks and cylindrical vessels
The term "strapping" is the term used to locating nozzles and other item on a tank or cylindrical vessel.
Start by finding a nozzle with a relative known location on the tank, either the inlet or discharge nozzle.
Start a sketch with this nozzle located on your tank with orientation to either plant or true north.
Walk around the tank and add other nozzles and items that you need to locate.
On your sketch, place a nozzle number and a spot for both a tape reading and elevation be each item you are locating.
Go to your first nozzle and set the end of a 100ft or 300ft tape on the tank above the center of the nozzle.
Mark the location with a pencil or marker so you can refer to it again if need.
Either have a coworker hold it there or uses strong magnet to secure the end.
Start stretching the tape around the tank.
When you come to an item you need to locate, stretch the tape past the item and, using a blurb bob or another smaller tape to locate the center of the nozzle.
Continue around the tank till you have all your nozzles and items located.
We're not done yet.
With your nozzles and items located, start back around the tank with a smaller tape.
Measure from the bottom of the tank, either lip or top of concrete to the center of the nozzle.
Before you leave this nozzle, check and verify the projection of the nozzle, size, and rating.
Note all this on your sketch.
Take pictures of all the items that you have information on and refer the pictures to your sketch.
I usually have my iPad with me with a "whiteboard" application.
I will write "N1" and place the iPad on top or in front of the nozzle.
If I don't have or cannot use the iPad, I use a dri eraser board for the same process.
About the Author
Lee Smith is the Owner/Operator of Smith Design, CADWorx and AutoCAD experienced,