Inspection chambers for external sewers

The new generation of plastic manholes offer modern and ecological solutions that satisfy all the requirements regarding wastewater evacuation. Through the use of modern plastic manholes is ensured a complete tightness of the sewage network due to the sealed joints between these and the plastic pipes, thus the concrete manholes, the only elements from the sewage system (made today mainly with plastic pipes) that were not able to ensure the network tightness, are eliminated.   

The plastic manholes area of use is similar with the one of plastic sewage pipes, covering both buried sewage networks for wastewater and rainwater applicable for infrastructure and residential buildings, water evacuation in agriculture and industry or for drainage. The maximum temperature of the wastewater transported is the same as the one of the pipes that will be used for that network.    

Main features and advantages of plastic manholes

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You can find the complete range of products in the TeraPlast 2020 catalog.

Features and advantages of the Inspection chambers for external sewers

Tightness

The manhole raft is foreseen with sockets with elastomeric gaskets in order to ensure a perfectly seal joint with the plastic sewage pipe used in the sewage networks. The elements of the modular manholes are also sealing among them with the help of gaskets. This guarantees an absolute tightness of the sewage system. Manhole tightness is tested at a pressure of 0.5 bars.  

Hydraulic features

The plastic sewage manholes are foreseen with optimum flow profiles that ensure a safe water flow and eliminate the risk of water network clogging due to manhole obstruction

Resistance to chemicals

Plastic manholes, like pipes, have an extremely high resistance to the abrasion and aggression of certain chemicals that can be found in wastewater (such as sulphuric acid).  

Resistant and robust

Plastic manholes have all the advantages provided by this material: robustness, shape stability and flexibility. As it is well known, plastic products flexibility provides them better long-term durability than the rigid (concrete) because they have a better resistance to subsequent load charges. 

Simple installation and economic efficiency

All the components have a reduced weight that allows to be handled by one person (maximum 2 for large diameter manholes), which makes the installation easier and faster, without additional costs generated by other machineries.

Beside fast installation and simple handling it must be taken into consideration also the easier transport at a lower cost as well as the reduced space necessary for storage.

Lifetime

The estimated lifetime for this type of manholes is of 50 years, similar lifetime with the one of PVC pipes, proven in this case. All these features lead to numerous advantages for the companies that manage the sewage networks and their beneficiaries due to the savings that can be obtained as a result of: 

  • Lack of long-term repairs costs.
  • Reduced maintenance costs.
  • Reduced water treatment costs due to the elimination of groundwater infiltrations in the sewage. 
  • Eliminate the cost of soil pollution fines due to seepage.

Manholes with column from smooth pipe

Manholes with column from smooth pipe are modular, multi-element manholes that are recommended to be used in private parking, network connections and green spaces but as well in municipal, industrial or residential and commercial networks through the use of cast iron covers and other accessories for traffic.      

The maximum burying level is 6 m and the maximum level of the groundwater is 5 m. A manhole has three basic elements: 

  • The manhole raft (base);
  • Manhole column;
  • Manhole cover.

A.1. manhole subgroup contains 3 types of manholes with elevation column from smooth PVC pipe: D200, D315, and D400mm. 

Manholes with column from corrugated pipe

General information regarding plastic manholes, their advantages as well as the technical and economic arguments for their use are described at the beginning of the manhole chapter.   

Manholes with column from corrugated pipe are also are modular, multi-element and are recommended to be used in private parking, network connections and green spaces but as well in municipal, industrial or residential and commercial networks through the use of cast iron covers and other accessories for traffic. 

The maximum burying level is 6 m and the maximum level of the groundwater is 5 m. A manhole has three basic elements:

  • The manhole raft (base);
  • Manhole column;
  • Manhole cover.

A.2. manhole subgroup contains 5 types of manholes with elevation column from corrugated pipe: D340, D353, D355, D670-Tegra 600 and D630-Pro630.

The “D” initial refers to the exterior diameter of the corrugated column for manhole elevation.