Want to more accurately load and unload your trailer? We’ve got the tool for you — Trailer Calibration Charts. In this blog, we’ll teach you what trailer calibration charts are, how to use them, and where you can find them. Keep reading to find out more…

(FYI: Trailer calibration charts are also known as tank strapping charts. For consistency, we’ll stick with the term “trailer calibration charts.” But, just know tank strapping charts also mean the same.)


What is a Trailer Calibration Chart?

Measuring the liquid in a trailer is easier said than done. Luckily, with Liquid Trucking’s new trailer calibration chart, drivers can accurately measure the volume of liquid in their tank based on the liquid level. The advantage of using a chart like this is that it simplifies the tank calibration process and it improves tank estimates. Ultimately, it makes measuring levels so much easier and timely. Plus, not all tanks are linear, which makes calculating their volume quite difficult.


Where to Find Liquid Trucking’s Charts

The link for the trailer calibration charts can be found on the homepage of Liquid Trucking’s website under the “Resources” tab. For drivers using the DeliveRecon app, they can be found on the left-hand menu. 

Also, did you know that most of the newer trailers also have this chart on a metal plate on the side of the trailer?


How to Use

Once you’ve found the online link, you can enter your trailer number and your chart should pop up.

The first thing to note is whether it’s an “innage” or “outage” strapping chart.

Innage – is measuring the amount of product in the trailer from the bottom of the tank to the top of the liquid, which is not necessarily best practice.

Outage – is measuring the amount of empty space between the top of the trailer and the top of the product. This is typically measured from the bottom of the manhole ring collar to the top of the liquid. If the outage chart has a bunch of asterisks for the first 8 inches or so, then it is measuring to the top of the rim where the manhole seals. Using an outage chart is the best way to go about it and it makes a difference, so it is important to note which chart you are going off of.

Once you know the chart’s type, you can start measuring. Find the closest ¼ of an inch to your measurement and that will be your total capacity. For instance, using the example chart below, if you measure 3 ¼ inches of liquid in your tank, the chart tells you that it equates to 129 gallons of liquid. If you measure 7 inches, you have 402 gallons of liquid. 

trailer calibration chart

In most cases, the volume of the tank is much more useful than a linear measurement. Primarily, the height of the liquid will be taken and then will be converted to a unit of volume, such as gallons or liters. 

It’s important to note that not all trailers are the same, so not all measurements will be the same. Each chart will have to be customized to the specific tank being measured. Just think about it, one foot of liquid in a small tank is much different compared to one foot in a large tank. 

As you might notice, not all charts are measured using the same increments. Some are in inches; whereas others are in feet. In Liquid Trucking’s case, they are measured in inches and as closely to ¼ of an inch. 


When to Use

The drivers at Liquid Trucking use the trailer calibration charts when filling the trailer to capacity at most loading locations. The customers may also use them when loading the trailers for the drivers and need to know the proper loading information. 

All in all, these charts are primarily used for loading, but they can also be used for unloading when you only want to unload a partial amount of liquid from the trailer. 


Closing Thoughts

Using a trailer calibration chart (aka tank strapping chart) can improve your accuracy and efficiency when loading and unloading your trailer. Who wouldn’t want that? It’s an invaluable tool to use as a driver and as a company. If you’re ready to utilize Liquid Trucking’s charts, head over to their website and click the “Resources” tab. For more information about how to read the charts or take measurements, please call 844-GO-TANKS.