The Manholes must be installed in accordance to WMA “Best Practice Paper”. The following major steps are involved during the installation.
2. Setting the IC
3. Positioning the pipes
For technical details and guidance on the installation procedure, please contact Duraco.
The following precautions should be taken:
- Residents of the housing units should not tamper with the manhole.
- No constructions or extensions to existing building should be allowed within 1 metre of any manhole.
- No loading of whatever type should be allowed on manhole.
Where not recommended to install manhole
The sewer manhole should NOT be used in the following site conditions:
- Where numerous 90º elbows may become necessary within the household property connection pipework to fit into the fixed benching and haunching of the manhole.
- In cases of high water table – which may cause uplift. The minimum distance between the bottom of the manhole and the water table shall be 1.2 metres
- In marshy lands
- At old sites of cesspits and leaching fields – where compaction to the standard conditions cannot be ensured.
A manhole or an Inspection Chamber is a vertical access chamber from the ground surface to the sewer network or other underground utilities. Manholes are usually positioned at a junction to allow cleaning, inspection, connections, and repairs.
By definition, an inspection chamber is a drainage or sewerage fitting used to connect drainage or sewerage installations. It also serves the purpose to change the direction of drainage or sewerage runs, which terminates at ground level with a riser shaft of 200mm minimum outer diameter and an inner diameter of less than 800mm.
Whereas, a manhole is a drainage or sewerage fitting used to connect drainage or sewerage installations and/or to change the direction of drainage or sewerage runs, which terminates at ground level with a riser shaft of 800mm minimum inner diameter.
In general, manholes or inspection chambers should be provided in the following situations:
1.At all changes of direction on drains.
2.At all changes of gradient on drains.
3.At all drain junctions where cleaning is not otherwise possible.
4.Within 12m between two drains
5.At all changes in pipe diameter
Inspection Chambers are not large enough for man-entry but allow the drain to be reached from ground level. The European Norm EN13598/1 provides for Inspection chambers 475mm and 600 mm up to a maximum depth of 1,250 mm and are known as shallow inspection chambers. The chamber is capped with a PE covers for pedestrian area.
The European Norm EN 13598/2 provides for manholes 800mm and 1000 mm diameter. These manholes are large enough to allow for man-entry and make allowances for rodding and clearance while standing on the benching. The EN 13598/2 provides specification for manholes in traffic areas and deep underground installations. Duraco can supply manhole of diameter 800 mm and 1000mm at height and specification recommended by EN 13598/2.
Once installed, these plastic units will allow for effective rodding, cleaning and inspection, without compromising operator safety. It is extremely durable and resistant to attack by sulphates in the soil.
NOTE: When installed in traffic roads, the Manholes must be equipped with a reinforced concrete ring which fits around the access shaft and rest on firm ground around the manhole. A GRP or ductile iron manhole cover with a load ability of D400 should be fixed on the concrete ring.
Its one-piece molded design as well as its rubber joining device gives the chambers a complete tightness in the ground up to a height of 1250 mm for Inspection Chambers and 2000mm for Manholes over the stream.
The Chambers base has an integrated slope, in accordance with EN13598/1 and EN13598 /2, which is perfectly in keeping with the hydraulic profile of sewerage systems.
The Chambers range allows the connecting of PVC pipes with a various range of standard pipe sizes in diameter, starting from 110mm. Moreover, angular bypass pipes can be connected with the help of rubber joints. For technical advice, kindly contact Duraco.
Due to its light weight, the Chambers can be easily handled for installation on site. They can be installed by hand, without the use of lifting gear or other machinery. Besides, its cast-in-one-piece design makes the manhole adapted to fit into most environments.
It is molded with horizontal and vertical strengthening ribs, which provides a perfect stability and strength, meant to fit in its environment. This distinctive feature enables it to withstand static and dynamic loads of hardcore as well as the pressure of the ground. (MSB test results for our manhole are provided upon request)
Endowed with the quality and physical properties of the High-Density Polyethylene, Duraco manholes are not affected by chemical agents such as hydrogen sulphide (H2S) and do not need any specific maintenance. Kindly contact us for more technical details.