Polyethylene piping system for water supply

[keerthi sureshbabu]

Polyethylene (PE) material is the ideal choice for water piping; it does not corrode or form encrustations like traditional water piping materials (like steel, cast iron, PVC, concrete), it is inert, prevents water from ‘brown water’ phenomenon thereby maintaining the quality of drinking water. Polyethylene is strong, durable, flexible and weldable. Leak joints can be welded by conserving precious water through low leakage rate. Polyethylene pipes can with stand ground movements like floods, droughts and earthquake conditions. High density Polyethylene can be used to carry portable water, wastewater, slurries, hazardous wastes, compressed gas and chemicals. Polyethylene is a reliable pipe system which lends to no dig technology.. PE maintains optimum flow rate and has high resistance to biological buildup. Small PE pipes can carry an equivalent volumetric flow rate of same pressure that of other material such as steel, cast iron, concrete piping. PE pipes are joined by heat fusions. PE is available with color coding. This application was developed by American public works association. PE pipes can be coiled and easily manocurved around obstacles without any fittings. If needed even no trenchless techniques can be used to install, this reduces the total cost of the project
Europe initially used Polyethylene pipe system for gas mains for safety concerns; during use of iron pipe system there was number of explosions taking place. Following several explosives in the city the UK health and safety executive recommended replacing all iron pipes by Polyethylene for the pipes within 30m from buildings. This use led to development of high quality PE piping system. In London, Thames water mains were 150yrs old and they were losing over 30% of their water due to leakage problems. Hence they are solving this problem by replacing a large part of their network with Polyethylene pipes. In 2002 UK water industry research Ltd commissioned bodycote PDL to maintain a record of water main failures and develop a protocol for data collection of failure information. The report contained around 500000 mains failure in 350000km water mains. The data included main length and diameter of each material. A comparison of failure rate and seasonal observations on failure patterns for different piping material were done and fond out that Polyethylene pipes should the least leakage rate. In the year 2007, Thames water started the Victorian water mains replacement project. A number of trenchless techniques have been used in the project.
Arhus water supply Company in Denmark monitored water main failure rate for different materials. Nowadays plastic pipes constitute 73% of total water supply network (2003). There leakage data shows that PE pipes has less failure rate when compared to steel and cast iron pipes.
In 2008, an earth quake measuring 8 on richer scale hit Beichaun in China. This damaged the pipelines and access to clean drinking water was a major problem. Borouge joined with Lein aid and Singapore water association and launched ‘drop of hope ’project. This agreement completed 100PE pipe lines which carried water from reservoir to mobile water treatment system. The water treatment system used reverse osmosis, water from rivers and mountains is filtered through a system and then clean water is supplied for drinking.
The national hospital of pediatrics’ in Hanoi, Vietnam had problems of clean water supply. A project called ‘lifelines’ was done by Lein Aid and Borouge to supply clean drinking water from reverse osmosis treatment units.
In 2006, Borouge supported the Sri Sathya Sai central trust to bring drinking water supply in east and west part of Godavari district of Andhra Pradesh. The construction is completed and now clean drinking water is being supplied to east and west part of Godavari district. Malkapur in Maharashtra installed PE pipes for water supply. Maharashtra Jeevan Pradhikaran financed the project and the project was under taken by Kimplas piping systems and an EPC industry is supported by Borouge. This project was featured in CNBC documentary.
In many European countries PE piping system are well established for small and medium sized water distribution system. In countries where water shortage, water quality problems are faced, PE system can provide a safe drinking water and scarcity of water can be over come. Flexibility of PE refers to easy installation even in rural areas with minimum equipments and man power. Advance in plastic materials have played a vital role in replacing older water pipes. PE is used to create long lasting, corrosion and leak free water pipes that will transport clean water to houses.

[GOPI KANTA GHOSH]

Absolutely right but choice of poly must be appropriate...

[Valliappan Manickam]

The followic topic is the subject of research to assess the influence of additivies used in various manufacturing processes followed by many countries. Is there any Life Cycle Assessment study available for Indian conditions?

Are these pipes harmful to health and do they affect the taste and odour of drinking water?

Previous international studies have shown that plastic pipes can release substances that give an unwanted taste and odour to drinking water. It has also been suggested that some of these substances may be carcinogenic.

A recent study conducted by Norwegian Institute of Public Health showed:

•There are no health risks associated with drinking water from PEX pipes
•A few types of PEX-pipe may cause prolonged undesirable taste and odour if the water remains in pipes over time
•Although the taste and odour usually dissipate with use, water from two of the PEX types still had an unpleasant smell and taste after a year

There are other threats too, especially PVC pipeline network is prone for damage due to roadside digging for laying systems like Network Cables. The Geogrpahical Positioning Information available for such systems is limited. The important point we should notice here is that whether it is for underground or aboveground corrosion resistant application.

[Indresh N]

HI.

Awesome read.

I work in a firm, where we are involved in O&M of 24x7 water distribution to selected cities in North Karnataka.

we have installed HDPE and MDPE pipes for network, which has been proved best as mentioned in the article by Keerthi ma'am.

These materials provide best efficiency when used in looping designs. And the advantages as discussed above so no need to mention here.

Previously Govt water board had installed PVC pipes which have proven inefficient. our system has reduced losses to 12% which include theft and minor losses due leakage while damage by other agencies.

Soon the old distribution systems in some parts of the country will be replaced by HDPE pipe lines.

[keerthi sureshbabu]

hiii dwitikrishna.. even i don't have exact idea  about process testing... i just know its physical testing.. if i get to know i shall surely share the details .

Dwitikrishna Panigrahi said:

Thank Ma'm... A good article. In fact we use plastics heavily but do not know much about it. I would like to know more about the material knowledge particularly the process of testing right quality of plastics. Where can I get that.

[Indresh N]

Hi Dwitikrishna,

You will get details in internet. search in google for details on HDPE & MDPE pipes and their pressure ratings, diameters, durability etc..

the following link may help u.

http://www.jains.com/Pipefittings/hdpe.htm