What Is CSST Pipe? History and UK Gas Guidance

If you are a domestic heating engineer, you have almost certainly heard of CSST tubing, regardless of whether you actually use it on gas installation projects or not. But there may be some of you reading this who are in the construction industry (or planning on a project that requires the safe installation of gas) and still need to learn about CSST tubing, where it came from and all of the advantages CSST offers heating engineers, plumbers and domestic heating engineers. So for anyone unfamiliar with this incredibly beneficial gas installation method, we here at Flexigas have written this informative blog on the history of CSST tubing, plus all of the advantages using CSST offers the front-line gas installer.

CSST (or corrugated stainless steel tubing, to give it its full title), is a flexible gas pipe that conveys natural gas from the gas mains to any area that requires it in residential, commercial and industrial properties. CSST tubing was first developed and then patented in the 1980s in Japan as a safer gas installation method than the more traditional copper piping or black iron pipe method. Why Japan? Japan just happens to sit upon an area where several oceanic and continental tectonic plates meet. The constant friction between these tectonic plates results in 1,500 to 2,000 earthquakes every year. One of the main dangers from earthquakes is fires caused by gas pipes being ripped apart, so it will come as no surprise that the Japanese looked for ways to minimise the dangers from earthquakes. And so CSST tubing was born.

CSST is manufactured using stainless steel which, unlike copper or iron, is much more flexible under duress. This makes CSST much less likely to split apart during an earthquake, resulting in less fire damage. In fact, CSST is so flexible it can be bent to 90 degrees by hand, which not only makes it a gas installer's dream (as it can be easily manoeuvred around corners and obstacles during installation) but also makes it a much safer option compared to copper or iron piping.

After the successful launch of CSST tubing in Japan, the United States started using more and more CSST in its gas installations and there are now an estimated 500,000 CSST pipes installed in the US each year. Whilst it took the UK a little longer to catch on to the CSST revolution, many UK gas installers are now making the switch with CSST sales growing steadily year upon year.

Since launching in the UK market back in 2016, Flexigas has supplied CSST tubing and related products for UK gas pipework. Flexigas supports Gas Safe installers, merchants and specifiers with current technical documents, product guidance and practical installation support. Current Flexigas CSST points to check include:

• CSST can reduce routing time and joint count compared with rigid copper on suitable jobs


• Many routes can be planned with long continuous CSST lengths and fewer intermediate joints


• Flexigas CSST can be routed around many obstacles, subject to bend radius, sizing and support guidance


• Use the current Flexigas installation guidance and the correct cutter, preparation and fitting process


• CSST can reduce hot-work requirements compared with soldered copper routes where the installation design allows


• Flexigas CSST is supplied in coils with metre marking so runs can be planned and cut on site


• For current Flexigas DS availability and sleeve guidance, contact technical support. With Flexigas DS, Flexigas DS, ask the team for current DS support, document status and the right product route for the job


• The FG Bond allows you to safely earth Flexigas CSST


• Flexigas offers a wide range of fittings, copper transitions and accessories for Flexigas CSST gas pipework

So as you can see, since its inception over 40 years ago in Japan, CSST tubing is now one established alternative to copper and threaded steel or iron pipework, with selection depending on route, sizing, standards and installer competence. Is it time to begin your CSST journey with Flexigas? Head to our “Find A Stockist” page and look for your nearest supplier of Flexigas.

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