Plastic Piping for Submersible Sewage Pump Stations

[piffer]

What are the drawbacks of using FRP (plastic) piping within a submersible sewage pump station. Most U.S. municipalities that I work with standardize on ductile iron piping within a pump station. Plastic piping is commonly used in Canada, with excellent results. I am wondering if anybody can respond with logical reasons why plastic piping is not used...

 

[stanier]

Because the pumping station is part of an infrastructure with a 50 year or more life proven materials such a cement lined ductile iron are common. I am working on the upgrade of 300 pumping stations for Sydney Water. 99% of them are DICL.

The reasons given for not using plastic materials such as FRP are the fatigue life limitations of the product available. One has to consider the procurement practices of contractors and clients. With lowest price being the order of the day one then has to consider the quality of the product. DICL has a greater safety factor and is not susceptible to fatigue.


There is no reason that correctly design ABS, uPVC , PE etc could not be used. Provided that the fatigue allowance has been considered. The question of thermal expansion needs then to be considered.

All in all the additional design cost, special supports to accommodate thermal strain etc and allowance for fatigue would make plastic material more costly in such installations.

 

[patprimmer]

Nylon 11 or 12 pipe could also be considered, especially if the water is hot, or if the pipe is being used as a liner to repair coroded or cracked metal or concrete pipes.

The thin walls possible with the nylon pipe causes less loss of ID when used as a liner. It is gluable, and light weight, but the unit cost per metre is high compared to PVC or HDPE.

Nylon 11 pipe use as liners for decayed iron pipes was pioneered in Sydney Australia to repair our decaying 100 year old cast iron gas supply system. Nylon 11 was very succesfully used in this application for the reasons stated above

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Regards
pat

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