A tour of the factory of Marley Pipe Systems, a SAPPMA member, highlighted the importance of quality testing for commercial plastic pipes and the issues that have caused a reduction of quality in the industry. MARISKA MORRIS reports.
The Southern African Plastic Pipe Manufacturers Association (SAPPMA) was established in 2004 to address the ethics and quality of commercial plastic pipes for various applications, such as irrigation and water distribution. The organisation performs quality audits to ensure accountability and compliance with standards bodies and the minimum standards required by SAPPMA.
Its main concern is the service life of pipes for use in the long term. SAPPMA members include various parts of the commercial plastic-pipe industry, with about 17 pipe manufacturers accounting for 80 percent of the pipes manufactured in South Africa.
The frequency of SAPPMA quality audits depends on the performance of the manufacturers, but they take place at least every three months.
SAPPMA CEO, Jan Venter, notes: “If we pick up something suspicious, we will increase the number of visits.” One of SAPPMA’s members is Marley Pipe Systems. On May 9, SAPPMA visited the company’s factory in Rosslyn to highlight the importance of quality testing.
However, Brett Kimber, Marley Pipe Systems MD, pointed out how price has caused a decline in the quality standards of the industry. He said: “South African plastic pipes sell for less than their international counterparts. The price of the raw material increased by 75 percent from 2012 to 2016, while the selling price increased by only 25 percent.”
He added that manufacturers have to absorb the additional costs. Some companies have resorted to unethical practices in order to still make a profit, including using post-consumer (scrap) plastics in products. Post-consumer plastic often includes weaker, low-grade polymer. This reduces the longevity and quality of the pipes.
Pipes constructed from pipe-grade polymer last for 50 to 100 years. Replacing pipes is expensive and often very disruptive. Low-grade pipes don’t have the same longevity. Toxicity does not form part of the SAPPMA quality tests, as the national standards don’t allow for the use of post-consumer plastics in potable water applications, which means that the organisation would not pick up on scrap material used in pipes.
It is, however, working towards regulations to reduce price variations. Marley Pipe Systems has invested heavily in its own testing, which includes a hydrostatic (water-based) test, where the pipe is placed in 20ºC and 80ºC water for 160 to 1 000 hours, to determine its life expectancy.
Many of these quality tests are destructive. The sample products, along with rejected products, are recycled at the Marley Pipe Systems factory, but as the manufacturer uses in-house unprocessed and/or in-house generated recycled polymer, Marley pipes can be recycled and used in smaller, 40-mm to 110-mm pipes designed for non-pressure applications, subject to the materials complying with the minimum raw-material standards.
These pipes are tested at the factory to ensure that the material used still has the required properties to comply with the standards. Although Marley Pipe Systems puts quality first, it might not be enough.
“The company’s business model is not sustainable, because we refuse to use post-consumer plastics. We won’t compromise on quality, but this may affect the size of the company going forward,” Kimber concludes.