Preventing Damage Caused by Linear Expansion

The photo above shows damage cause by linear expansion of stainless steel tubing. Linear expansion can lead to damage ranging from unsightly workmanship to connection leaks and complete failure on CNG Fueling stations, CNG vehicle fuel delivery systems, CNG tube trailers or any system where high pressure CNG stainless steel tubing is being run and significant temperature changes are present.

The impact of thermal expansion and design solutions to combat this issue are well documented and I’ll leave deep dive reading and research to those that care to dig further. Engineering to design for the required expansion relief can be quite time, labor, and money intensive. The system design is should be dictated by the magnitude and risk of potential damage . Below are 5 approaches to relieve thermal expansion in your applications.

1. Natural design relief – Many times the natural path of the tube takes enough turns right, left, up and down to provide the expansion needed.

2. Single U-bend expansion loop


3. Reverse U-bend


4. Single coil- On vehicle systems coils can also be employed to allow for relative movement between connection ends of the tube as well as for thermal expansion absorption.


5. Multi-coil


Another critical element to get the most out of the expansion solution selected is to use the proper hardware and placement of the anchors securing the tubing. The anchors need to allow the tube bends & coils to move. Remember, the expansion is not disappearing from the tube circuit, rather, it is being absorbed by the expansion of the coil or bends.

How can InsightFuel help
On the CNG vehicle side, InsightFuel has the equipment and the expertise to not only manufacture the sometimes complicated bent tube designs, we also have the experience to guide folks to the easiest-to-manufacture, most economical-to-make and install assemblies. On the CNG fueling station side, we’re all about helping people build and repair stations faster and safer and that translates to less cost. InsightFuel employs some forward thinking in preparing for installations and repairs that eliminates costly in-the-field work.  More and more people are finding out that what we know at InsightFuel is just as important as what we sell.

I'm interested in learning more about InsightFuel

Kevin W. Dickey- General Manager

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