Only after the pipeline failed for the sixth time did experts begin to raise questions about its quality and the technology.

The pipes were made by Vinaconex at its factory in Vietnam, but with technology it bought from China. These fiberglass-reinforced pipes were provided by Vinaconex directly to the project.

Vinaconex was also an investor of a project to supply water to Hanoi.

When asked about fiberglass-reinforced technology, Dr. Vu Ngoc Anh, dean of the Hanoi Architect University’s Civil Engineer Faculty, said the technology has several certain advantages but only suits some kinds of construction works.

“The technology is still being used in many countries for clean water supply or waste water drainage works. However, one needs to think carefully about using it to discover if the material suits the works,” Anh said.

He said that fiberglass-reinforced tubes were not the most effective kind of material, although they have been popular because of the low prices.

Vinaconex, the investor, understandably did not use other kinds of tubes that are more elastic and heat-resistant. It chose material which had the lowest cost for production. In addition, the tubes could be made in Vietnam because Vinaconex has a factory specializing in making them.

According to Anh, fiberglass-reinforced tubes are more brittle than other products such as UPVC and HDPE plastic tubes used in other water supply works.

The tubes are manufactured by several domestic enterprises, including Tien Phong and Binh Minh Plastics Company, as well as Europipe.

The products have met Vietnamese and international standards, including ISO 4422-1990, ISO 4427-2007, or the German standard DIN 4262-2001.

“Plastic tubes are softer than fiberglass ones. Therefore, they allow the pipeline system to operate safely even in the condition of weak land. Fiberglass tubes are fragile,” Anh explained.

However, experts said that the low-quality water pipeline should not be blamed on the fiberglass but rather on investors, designers and contractors.

Meanwhile, Hoang The Trung, former director of the Da River Water Supply Project Unit Management, has said that the contractor strictly followed all the procedure’s steps, but, to save money, he did nothing to improve the weak soil.

Trung also said that fiberglass was a high-class material, and it was a proper decision for the investor to use that kind of material.

When asked about the solutions to resume water supply, Vinawaco, the water supply company, said it would set up a second pipe system and draw up a plan to increase water exploitation capacity.

If this plan goes through, the investor would have to spend additional money on the work.