Frequently Asked Questions on Manholes

1. What benefit can be derived from the use of plastics manholes?
Small and medium size plastics manholes have low weight and can easily and quickly be transported, handled and installed without any special equipment. 
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2. What is the chemical resistance of plastic manholes in sewer pipelines? 
Plastic manholes can withstand all chemicals which normally occur in sewers, and therefore are regarded as very durable. 
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3. What are the differences during installation of plastic manholes compared to manholes of other materials?
Plastic manholes can be installed much easier due to their light weight, needing a smaller trench and providing huge flexibility of connections. 
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4. What are the hydraulic properties of plastic manholes in comparison with other materials?
Because of the smooth inside and flow profiles plastic manholes have excellent hydraulic properties. Due to these excellent hydraulic properties plastic manholes have a lower risk of obstacles or blockages. 
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5. How can plastic manholes be adapted to the final height of the pavement?
Plastic manholes have a telescopic cover solution which ensures adjustment of height and gives high flexibility and fast execution. 
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6. How does water temperature and ambient climate affect the durability of Plastic Manholes?
Plastic Manholes are resistant to a wide range of temperatures from -20°C to 45°C. No water is absorbed which can freeze in winter destroying the structure. It is well known that water freezing between concrete elements can destroy them, whereas plastic parts are not affected by the same conditions. 
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7. What is the most common inspection technique used in plastic manholes?
Using a camera is the most common inspection technique used today which gives safety and is time/cost effective. 
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8. What possibilities exist for making connections on site in plastic manholes?
By drilling a hole in the shaft and using a sealing ring it is very easy and fast to make an extra inlet on a plastic manhole on site. 
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9. How can plastics manholes withstand traffic loads?
Traffic loads onto the top cover are not supported by the plastic manhole but by the compacted soil around the manhole. 
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10. Are plastic manholes water tight?
Similar to plastic sewerage piping systems, plastic manholes show no leakage which results in no contamination of the soil by ex-filtration and no infiltration of the ground water into the manhole. 
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