Does ultrasonic level measurement work with a standpipe?

The easy answer: Yes.

But in a recent webinar on choosing the best level technology for your application, the more specific answer is this: Yes, AS LONG AS you pay attention to the unit specs and a pretty simple rule of thumb.

Siemens ultrasonic level in a standpipe
According to Siemens level specialists, you need to know a couple things:

Standpipe 3:1 Ratio

This rule of thumb gives you a pretty good indication of whether the ultrasonic transducer will work in a standpipe (or nozzle). The necessary ratio of standpipe diameter to height is 3:1. So if you have a 6″ diameter standpipe or nozzle, and it’s 18″ high, your transducer should work without problem.

And ideally, the standpipe nozzle should be cut at a 45° angle (as shown), and the standpipe side wall should be seamless and smooth.

Proper Installation

Check the instruction manual for your ultrasonic sensor for any special installation considerations or guidelines. Proper installation is key to making sure the time-of-flight echo is received back at the transducer.

Also remember that there’s a default blanking distance (dead zone) from the face of the transducer. According to Siemens, if your standpipe height is 6″ or less, you can use the factory default blanking distance. If the overall standpipe height is more than 6″, you should increase the blanking distance to 4″ beyond the bottom of the standpipe.

Last but not least, all applications should be reviewed prior to purchase or installation. Lesman’s factory-trained sales team and Siemens technical engineers can help.

For more information, see Siemens ultrasonic sensor installation tips. Need an engineering review of your application? Fill out an ultrasonic level application datasheet from


Lesman Instrument Company is the authorized Siemens representative in Illinois, Indiana, Missouri, Paducah KY, Wisconsin, and Michigan’s Upper Peninsula. If you are located outside that area, you can find your local sales office or get technical assistance by calling 800-365-8766.

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