Olympus Logo
Olympus LogoOlympus Logo
Application Notes
Back to Resources

Wall Thickness of Plastic Pipe

SubSurface Crack Detection


Measurement of wall thickness and concentricity of plastic pipes.


Manufacturers of plastic pipes must monitor uniformity of wall thickness around the circumference in order to meet product specifications. If a pipe is too thin it may fail in use, and if it is too thick the manufacturer may be wasting money on excess resin. Ultrasonic gaging provides a quick and reliable way to measure wall thickness with no need for ID access or for cutting the pipe. Pipe thickness can also be measured after installation if required.


The recommend instruments for plastic pipe and tubing measurements are the Model 45MG (with Single Element Software) and 38DL PLUS thickness gages. A variety of transducers are used, selected according to the diameter and wall thickness of the pipe or tube being measured. For the most common sizes of plastic pipes, choices include the M112 (10 MHz) for polyethylene and PVC wall thicknesses from approximately 0.020" to 1" (0.5 mm to 25 mm), and the M1036 (2.25 MHz) for thicknesses greater than approximately 1" or 25 mm. Contact Olympus for specific recommendations.

Very small diameter tubing (less than approximately 0.125" or 3 mm diameter) and hot pipe represent special cases that are discussed in these application notes:


Plastic pipe thickness measurement represents a common application for ultrasonic gages and is usually a simple pulse/echo test in which a gage measures round-trip pulse transit time and uses that time measurement plus the speed of sound in the test material to calculate thickness. As with any ultrasonic test, sound velocity must be calibrated on a sample of the material being measured according to the simple procedure described here. Once that has been done, it is necessary only to apply a drop of liquid couplant to the test point, touch the transducer to the surface, and obtain a reading. Measurements take only a few seconds each and can be recorded on gage dataloggers for documentation and analysis.

For further information on this or any other ultrasonic test application, contact Olympus.

Olympus IMS

Products used for this application


The 38DL PLUS is an advanced ultrasonic thickness gage. Uses dual element transducer for internal corrosion applications, and has features that include THRU-COAT technology and echo-to-echo. Uses single element transducers for very precise thickness measurements of thin, very thick, or multilayer materials.


The handheld 45MG ultrasonic thickness gage is packed with measurement features and software options. This unique instrument is compatible with the complete range of Olympus dual element and single element transducers, making this gage an all-in-one solution for virtually every thickness gage application.

Magna-Mike 8600

The Magna-Mike is a Hall effect thickness gage that uses a magnetic probe to perform accurate measurements on nonferrous and thin materials such as plastic bottles.
Sorry, this page is not available in your country

Let us know what you're looking for by filling out the form below.