Buried Network

Buried Network
Technical assistance

Tel. +33 (0) 3 83 80 78 08

tcbatiment.sgpam@saint-gobain.com

BURIED PIPE SYSTEMS

ITINERO® pipes can be used in below-ground applications. Buried pipes are subject to mechanical strain due to the weight of the ground and possible wheel loading when laid under an area where traffic circulates.

The mechanical performance of buried pipework is to be considered like a pipe/soil system: the interaction of the pipes with the surrounding soils depends on their stiffness or flexibility, and the type of laying condition selected.

The choice of bedding and backfilling depends on the depth at which the pipes have to be laid, and the size and strength of the pipes. Standard EN 1610 “Construction and testing of drains and sewers” applies to drains normally buried in the ground and normally operating under gravity.

 

Installation parameters are established according to:

  • Soil type (see groups below)
  • Quality of compaction of the embedment
  • Behavior of the pipe (rigid for cast iron)
  • Presence of wheel loads or not > Particular conditions (groundwater table, etc.)

BURIED PIPE SYSTEMS

ITINERO® pipes can be used in below-ground applications. Buried pipes are subject to mechanical strain due to the weight of the ground and possible wheel loading when laid under an area where traffic circulates.

The mechanical performance of buried pipework is to be considered like a pipe/soil system: the interaction of the pipes with the surrounding soils depends on their stiffness or flexibility, and the type of laying condition selected.

The choice of bedding and backfilling depends on the depth at which the pipes have to be laid, and the size and strength of the pipes. Standard EN 1610 “Construction and testing of drains and sewers” applies to drains normally buried in the ground and normally operating under gravity.

 

Installation parameters are established according to:

  • Soil type (see groups below)
  • Quality of compaction of the embedment
  • Behavior of the pipe (rigid for cast iron)
  • Presence of wheel loads or not > Particular conditions (groundwater table, etc.)

Backfilling recommendations

Backfilling recommendations from DN 100 to DN 300, with or without traffic loads (according to EN 1610).

Two main solutions have been retained from the EN 1610 recommendations, taking into account both ease of installation and knowledge from experience of rigid pipe systems. For compaction, the most adverse hypothesis was retained. These solutions maximise the advantage obtained from cast iron’s mechanical properties: depth of cover it can withstand, possible backfilling with native soil removed, thereby limiting damage to the environment, etc.

Dimensions are in mm.

* Detrimental materials = stones, tree roots, rubbish, organic material, clay lumps (>75 mm), snow and ice.

Backfilling recommendations

Backfilling recommendations from DN 100 to DN 300, with or without traffic loads (according to EN 1610).

Two main solutions have been retained from the EN 1610 recommendations, taking into account both ease of installation and knowledge from experience of rigid pipe systems. For compaction, the most adverse hypothesis was retained. These solutions maximise the advantage obtained from cast iron’s mechanical properties: depth of cover it can withstand, possible backfilling with native soil removed, thereby limiting damage to the environment, etc.

Dimensions are in mm.

* Detrimental materials = stones, tree roots, rubbish, organic material, clay lumps (>75 mm), snow and ice.

Recommendations for sewage pipe systems

Based on our experience in buried pipe systems and the French origin of our company, we have applied the French Fascicule 70 calculation model (recommendations for sewage pipe systems according to the pipe material).

The table below gives values for depths of cover according to the Fascicule 70 calculation, considering rigid pipes.

  Depth of cover values (m)
    Without traffic loads With traffic loads
Solution 1 Min.** 0.3(1) 1
  Max. 3.2 2.4
Solution 2 Min.** 0.3(1) 0.3
  Max. 6 (or 9) 6 (or 9)

 

Recommendations for sewage pipe systems

Based on our experience in buried pipe systems and the French origin of our company, we have applied the French Fascicule 70 calculation model (recommendations for sewage pipe systems according to the pipe material).

The table below gives values for depths of cover according to the Fascicule 70 calculation, considering rigid pipes.

  Depth of cover values (m)
    Without traffic loads With traffic loads
Solution 1 Min.** 0.3(1) 1
  Max. 3.2 2.4
Solution 2 Min.** 0.3(1) 0.3
  Max. 6 (or 9) 6 (or 9)

 

Other precautions

  • Clearance at each joint between the couplings and the granular bed to allow sufficient space, and to prevent the pipe from resting on the joints. (see EN 1610 §8.5.4)
  • Testing for pipe system leak tightness according to EN 1610 §13.
  • Identification of the pipework with a netting for example.
  • Furthermore, check that these specifications do not contravene other local or national regulations or recommendations for installation.

For any other case, other diameters or buried systems under the bottom slab, please contact our technical support team: tcbatiment.sgpam@saint-gobain.com

Other precautions

  • Clearance at each joint between the couplings and the granular bed to allow sufficient space, and to prevent the pipe from resting on the joints. (see EN 1610 §8.5.4)
  • Testing for pipe system leak tightness according to EN 1610 §13.
  • Identification of the pipework with a netting for example.
  • Furthermore, check that these specifications do not contravene other local or national regulations or recommendations for installation.

For any other case, other diameters or buried systems under the bottom slab, please contact our technical support team: tcbatiment.sgpam@saint-gobain.com

Pipe system set in concrete

Where the pipe system is to be set in concrete, a minimum 2.5 cm width of concrete on every side has to be respected because during and after its curing, the concrete will be subject to shrinkage and carbonation. To reduce the natural rigidity of the concrete and its strain, a suitable flexible joint can be installed at intervals. This could be made of a compressible material (e.g. expanded polystyrene), be placed next to a pipe joint, and conform to the full cross section of the concrete. (See Fig). Refer to local best practice. Furthermore, the pipe system should not be in contact with the concrete's metal reinforcements. Surround should not be carried out until the pipework has been tested and inspected.

Pipe system set in concrete

Where the pipe system is to be set in concrete, a minimum 2.5 cm width of concrete on every side has to be respected because during and after its curing, the concrete will be subject to shrinkage and carbonation. To reduce the natural rigidity of the concrete and its strain, a suitable flexible joint can be installed at intervals. This could be made of a compressible material (e.g. expanded polystyrene), be placed next to a pipe joint, and conform to the full cross section of the concrete. (See Fig). Refer to local best practice. Furthermore, the pipe system should not be in contact with the concrete's metal reinforcements. Surround should not be carried out until the pipework has been tested and inspected.

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