PVC Pipe Industry News

Iron corrosion is one of the most complicated and costly problems facing Australian water utilities and Government authorities.
Corrosion is the degradation of metal and is caused by oxidation or chemical action. If corrosion occurs in water distribution pipelines, valves and fixtures, it can cause the degradation of the quality of drinking water.

Iron and sulphur bacteria contribute to the corrosion of iron and steel bore pipes and drinking water mains.

Australian guidelines seek to ensure that drinking water is free of microorganisms that can cause disease.

The appearance, taste, odour, and ‘feel’ of water determine what people experience when they drink or use water and how they rate its quality; other physical characteristics can suggest whether corrosion and encrustation are likely to be significant problems in pipes or fittings.

PVC pipe is a proven and extremely durable alternative to traditional corrosion-prone pipe materials. Unlike metal piping, PVC won’t rust or corrode over time because it does not react with air and water. This eliminates the need to specify corrosion protection methods that have become standard procedure for piping.

With PVC, long-term durability is not compromised.

The majority of water piping installed in the 20th century in Australia is cast or ductile iron, which was expected to provide water utilities with 50 to 100 years of trouble-free service. Unfortunately, these pipes are susceptible to corrosion and subsequent breakage.

Most people believe that old age is the primary contributor to iron water main breaks. However, the problem isn’t age. It is corrosion. Indeed, in South Australia some water mains installed in 1872 have continued to perform well.

A University of Newcastle, Australia report from Centre for Infrastructure Performance and Reliability had the below conclusion.

A corroded section of cast iron pipe the size of a tissue box in Sydney’s northern beaches is to blame for the flooding of a mansion-dotted hillside and a sinkhole that caused part of the road to collapse and a fire truck to crash.

Ninemsn reported that Sydney Water confirmed that a cement-lined water main running through The Serpentine gave way due to a minor defect in the pipe's protective coating.

They said investigators had found a corrosive patch measuring 20cm by 10cm, slightly smaller than the size of a standard tissue box.
As a result of the defect, the pipe became corroded by soil, causing a section of it to break away.

Both here and overseas, several cases have been reported where ground surface collapsed leading to sinkholes near aging pipes prone to corrosion. Factors causing pipe deterioration and the effect of corrosion pits on the structural performance of pipes have been investigated by several researchers with emphasis on cast iron pipes. It was concluded that corrosion was the main factor influencing pipe deterioration. Cracks initiated at corrosion pits lead to progressive circumferential and longitudinal cracks in addition to blown-out holes.

Unlike metal piping, PVC pipe won't rust or corrode over time because it does not react with air and water the way metal does, which results in a significantly longer lifetime of the pipe.

Consequently, PVC pipe is the most cost effective and sustainable solution in applications where soil is aggressive. PVC pipe can be expected to outlast alternative pipes without the need for protective coatings or liners. PVC pipe is a proven and extremely durable alternative to traditional corrosion prone pipe materials.

Recognised by state, national and international agencies and standards organisations, it has been a benchmark since it was introduced in the sewer, water and drainage markets.

One of the issues that Think Pipes Think PVC has tackled over the past three years is that of iron corrosion in Australia water due to outdated Iron pipe systems degrading water quality. As well as being a substantial health hazard to the community, corrosion is also the number one reason for burst water mains across the country.

Today in Glen Waverley, Melbourne a burst pipeline sent residents scrambling from their homes as water was sent shooting up into the sky an estimate up to 80m. Roofs collapsed and extensive property and cars were damaged.  The main supplies water from Silvan Reservoir to more than 100,000 homes and businesses in Melbourne's southeast.

I recently attended the Annual Conference for the Uni-Bell Pipe Association in the US, the largest gathering of PVC pipe and fitting manufacturers in the world. At the conference I met with Dr  Steven Folkman who recently released a highly detailed, researched and comprehensive study on water main breaks for the US and Canada. His most recent report, Water Main Break Rates In the USA and Canada: A Comprehensive Study April 2012, gave some staggering figures into the cost of corrosion in terms of water quality and failure rates of iron, cement and steel water pipes and the impact and cost of this onto the US and Canadian economy.  In our own Australian industry, with many water pipelines being cast or ductile iron and having been in service for 50 years or more in many cases, I would expect these results would be similar in our local market.