Frequently Asked Question

Check out our list of frequently asked questions below for helpful answers to some of the common inquiries we received

1. Where can I find engineering practices such as the procedures, precautions for electrofusion welding for fittings with PE pipes?

Engineering practices for electrofusion welding of PE pipes are described in installation manuals provided with Kimplas products. Also detailed procedure can be followed from National Grid Transco instructions.

2. Can PE pipe be joined by solvent coupling joints?

No. At this time, there are no known adhesives or solvent cements that are suitable for pressure sealing or that have sufficient strength characteristics to join PE pipes.

3. How are PE pipe segments joined or connected?

PE pipe is easily and dependably joined using the standardized butt-fusion, electrofusion, saddle fusion, mechanical jointing procedures.


In Butt Fusion process, matching ends of the pipes to be joined are aligned and heated with standard tools until the surfaces become molten. When engaged under moderate pressure, the molten faces flow together forming a homogeneous joint. In Butt Fusion, jointing of pipes of different wall thickness is not possible.


In Electrofusion Process, pipes of different thickness are clamped after surface preparation, electrical energy is passed through embedded coils using fusion machine. Heat generated by coils melt both pipe & fitting surface forming a monolithic, homogeneous joint that as the material cools, yields joints that are as strong as or stronger than the pipe itself.

4. What are the causes of electrofusion joint failures?

The electrofusion procedure should be done by skilled person. There are so many reasons for joint failure like Improper scraping of the pipes, improper holding & alignment of pipe, machine calibration – fusion machine gives lesser voltage, excessive scraping of pipe-too much loose pipe.

5. Why do you scrape the pipe before electrofusion?

Scraping is necessary to remove the oxidized layer formed on pipe, also for easy movement of fitting on pipe surface.

6. Is scraping necessary for spigot outlet of saddle before electrofusion?

There is no need of scraping on spigot outlet as fitting is packed in plastic bag. Do not open plastic bag until the pipe surface become ready for electrofusion.

7. Why to do re-rounding of pipes?

During jointing of two pipes by using EF coupler, if the pipe’s cross section shape has become “Elliptical”, then it is necessary to re-round the pipe. The elliptical shape does not fit correctly in the coupler socket. Only two ends of bigger lobe touch the coupler & there is a gap between the smaller lobe & the coupler, making the joint weak. Re-rounding clamps make the pipe round when it is clamped near the coupler, thus making the contact area to the maximum. Hence the joint becomes sturdy after electrofusion.

8. What will you do if power goes off after half of fusion time?

Every TRUSTLENE fitting has ability to get fused twice. If there is a power failure amidst electrofusion process, wait for complete time of cooling and again repeat the procedure of fusion from start when power supply is continued.

9. Is it possible to puncture PE pipe; how is that repaired?

Yes. PE Pipe get punctured if depth of scratch is greater than 10 times the thickness of pipe. It can be replaced by a jointing coupler or you can fix it by repair saddle.

10. Where can I find details for compatibility of TRUSTLENE fittings with PE Pipes of different SDR’s and PN Rating?

Engineering practices for compatibility of TRUSTLENE Fittings with PE pipes of different SDRs and PN ratings are described in Kimplas Technical Specification Manual.

11. What does the term SDR mean?

A Standard Dimension Ratio (SDR) is the average outside diameter divided by the minimum wall thickness. SDR is based on ANSI preferred number series. The use of SDR’s enables manufacturers to produce pipe and fitting to a set of standardized DR’s. Mainly SDR’s include 9, 11, 13.5, 17, 21, 26, and 32.5.