# Calculating Volumes of Tank Farm Secondary Containments

Hello,

I’m currently working on a project to quantify the volumes of the secondary containment dikes surrounding storage tanks in a tank farm. I am digitizing volume polygons along the top of the containment dikes in Global Mapper, based upon the DSM, and importing them in to compute the volume of the area within the dikes. Do the volume quantifications exclude the tank volume (up to the level of the containment dike) within the area being calculated? Is there a method to include that volume of the tank as well?

Also, is there a better way to define the area to be calculated than digitizing along the top of the dike in Global Mapper? Using the built-in volume tool to digitize the boundary gives a different result every time I use it which is less than desirable for doing somewhat accurate calculations.

Here is an example of what I’m working on:

Andrew,

If I understand correctly, you are wanting the volume of the containment area, including and excluding the tank correct, the ring outlined by the circular polyline?

One way I think I would do it is clip the tank and pipe rack out of the point cloud dataset. then create a polyface surface over those areas to mimic the existing ground elevation through those areas, enable those surfaces to be used in the DTM creation, that will give you a file you can use in GM without the tank and facilites.

I feel you should be able to use Pix4D volume function to determine your volume of the containment area by selecting the top of berm…

To determine the tank volume I would set the boundary max elevation to match the top of berm - that should leave you a ring of points through the tank like a cross section - you should be able to then volume the tank.

Hello Andrew,

I am not sure if I understand well what you want.

I think you could do everything that you want in Pix4D. You can easily draw the boundary and you can include or exclude the points that you want.

The volume is computed based on the DSM and the DSM is computed based on all of the points except for the ones in the disable layer.

You can compute the first DSM including everything, compute the volumes that you want and then, you can compute a new DSM excluding the points that you want.

Regards.