A line carrying acid, chlorine or hypochlorite discolours, stiffens or starts to "sweat". Or the medium picks up contamination from the line itself. In many of these cases, the root cause is the material. ECTFE is a fluoroplastic with high resistance to acids and oxidising media and very low permeation. In this article you will learn when ECTFE tubing is the right solution, when another fluoroplastic is a better fit, and which data you need for a complete enquiry.
Tubing rarely fails all at once. It usually starts with small signs that are only taken seriously later.
Tubing made from standard plastics or rubbers is not designed for this load. The purchase price is low, but the total cost over the service life is often higher.
ECTFE is a copolymer of ethylene and chlorotrifluoroethylene. That combination delivers properties that address each of the failure modes above:
Because ECTFE is melt-processable, extruded ECTFE tubing is made in a continuous process, unlike PTFE tubing, which is paste-extruded and sintered. So where is the bottleneck? Rarely in the material itself. Problems with an ECTFE line almost always start in the specification.
A bend radius that is too tight makes the tube kink. A wall thickness that does not match the working pressure leads to early failure. And a pressure rating chosen without considering the operating temperature gives a false sense of safety. A good material still needs the right dimensions.
ECTFE is mainly used where aggressive or oxidising media meet strict requirements for purity or safety. Typical applications:
A rigid ECTFE pipe suits fixed process lines, while flexible tubing is the better fit for dosing and instrumentation. Thin-walled ECTFE sleeving is also used as a chemically resistant protective sleeve over cables and sensor lines.
ECTFE is not always the best choice. Within our range of fluorine plastic tubing there are alternatives:
Unsure which material fits? Our blog on ECTFE vs ETFE compares the options in detail.
Record the medium and its concentration, the operating temperature including peaks, and the working pressure. Include cleaning agents and flushing fluids that pass through the same line. For resistance per medium, see our article on the chemical resistance of ECTFE.
Polyfluor uses ISO 7751 as a guideline for the ratio between working pressure and burst pressure. Keep in mind that the allowable pressure drops as the temperature rises. See the working/burst pressure ratio according to ISO 7751.
Decide how the line will be connected: ECTFE fittings, flanges or a direct coupling. Specify the required lengths and any finishing. Custom ECTFE tubing, cut and prepared to length, avoids work on site and the extra leak points that come with it.
With the data from steps 1 to 4, you have a complete enquiry. At Polyfluor, ECTFE tubes are not a standard stock item: dimensions and designs are supplied on request. The more complete your specification, the faster and more accurate the quote.
A water treatment plant doses sodium hypochlorite through a flexible line. The existing tube discolours within a short time and hardens. Metal brackets around the line start to corrode. Two mechanisms are at work here: attack by an oxidising medium and permeation of chlorine compounds through the wall. ECTFE addresses both.
The open question in a case like this is not the material but the execution. What bend radius does the route require? What pressure does the dosing pump deliver? And how will the connections be made?
ECTFE is a strong choice for lines carrying acids, chlorine, hypochlorite and ultra-pure chemicals. It is chemically resistant, has very low permeation and can be used from −75 °C to +150 °C. The weak link is rarely the material; it is the specification. If you define medium, temperature, pressure, dimensions and connections up front, you prevent early failure and you will also know when PFA, FEP or PTFE is the better option.
Looking for tubing in ECTFE made to your specification? View our ECTFE tubes or request a tailored quote. Our specialists are happy to think along with you on dimensions and design.
It is used to transport aggressive, oxidising or ultra-pure media, such as acids, chlorine and sodium hypochlorite. Typical sectors are the chemical industry, semiconductors and water treatment. The low permeation keeps the medium pure and limits emissions to the environment.
In practice the terms are often used interchangeably. A pipe usually refers to a rigid, thicker-walled design for fixed lines; a tube or hose is more flexible and suits bends and moving parts. The material is the same; wall thickness and diameter determine the behaviour.
ECTFE can be used continuously from −75 °C to +150 °C and short-term up to 180 °C. Keep in mind that the allowable working pressure decreases as the temperature rises, so always check pressure and temperature together.
Yes. ECTFE tubes are supplied on request, in the dimensions, lengths and design you need. Provide the medium, temperature, pressure, inner diameter and wall thickness, and our specialists will prepare a quote.
Choose PFA for temperatures above 150 °C or when maximum purity is required. ECTFE is often the stronger choice for oxidising media and where low permeation is important.