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Title:
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Materiaalkeuze voor filterbuis toegepast in vervuilde grond van project Haarlem Materiaalkeuze voor filterbuis toegepast in vervuilde grond van project Haarlem
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Author(s):
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Published by:
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Publication date:
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ECN
Environment & Energy Engineering
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2-7-2007
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ECN report number:
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Document type:
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ECN-E--07-048
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ECN publication
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Number of pages:
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Full text:
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40
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Download PDF
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Abstract:
Visser & Smit Hanab BV has to make a materials selection for piping in contaminated soil. ECN-Engineering & Services was asked to make a materials advice based on corrosion considerations. A life time of 50 years is expected to be necessary.
From information made available regarding the composition of the soil and groundwater, it is concluded that the soil is to be considered very corrosive.
Carbon steel, stainless steels and aluminium alloys were considered as metallic options. With respect to metallic piping it is concluded that these can only be applied when using additional protective measures. These protective measures include coating and/or cathodic protection. Additionally, periodic inspection must be performed and a maintenance plan is to be set up. For the periodic inspection, a 4-5 year inspection interval is suggested. The application of metallic piping is not advisable. If a metallic material is selected, a stainless steel with a minimum of 20% Cr and 4% Mo is the best option. Additional measures regarding protection must be made, e.g. cathodic protection and regular inspection.
Several plastics, (HD)PE, PVC, PA and PTFE, were evaluated using literature and internet data. PVC is not resistant against most of the chemical components found in the soil and the groundwater. HDPE shows a much higher resistance, although less resistant against ethylene benzene and tolueen. PTFE performs best with respect to these chemicals.
With respect to the inner environment of the pipe, the transported groundwater, similar considerations can be made. From the presented information it is concluded that the pipe may well be partly drained occasionally. This means that corrosive components can be concentrated locally. With respect to mainly metallic piping, locally very corrosive conditions can occur, resulting in fast corrosion starting in the inner surface of the pipe. Although toluene, benzene, ethylene benzene and xylenes evaporate quickly, some concentration can not be excluded.
If plastic is selected as material for the piping, the pipe is to be laid in a bed of clean sand or soil. This to ensure an equalized stress distribution over the pipe and to prevent local loads by sharp objects in the soil.
Therefore, it is concluded that PTFE is the best option for pipe material, with PE as second best.
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