Suitable installation location
Underground pumping stations are ideal for keeping noise and odours contained. They can be installed in green spaces and courtyards, as well as in traffic areas (e.g. roads, car parks or access roads). It is important to ensure that the manhole cover can withstand vehicle traffic (see also load classes for drainage technology). In addition, the relevant regulatory requirements must be observed. In drinking water protection or flood-prone areas, special requirements may apply to the installation of pumping stations, or it may even be prohibited altogether.
The chamber must not be within the influence zone of adjacent foundations, i.e. minimum distance a = distance between the lower edge of the chamber and the lower edge of the foundation: a = ΔH x 1.73
Groundwater
For pumping stations installed underground, the depth to which the chamber is submerged in the groundwater must be taken into account and checked against the selected product. Most KESSEL pumping stations may be submerged in groundwater to a depth of up to 3 metres without the need for additional measures to prevent buoyancy.
installation depth
The installation depth of a pumping station is usually determined by the incoming main drainage pipe. All other outlets will be aligned with this. It is important to determine this depth precisely from the outset, as it determines the entire system layout. This allows for a complete configuration to be carried out.
The following components must always be included in the planning:
- Inlet pipe
- pressure pipe
- Ventilation pipe (for sewage lifting systems and closed lifting stations)
- cable duct
- Location of the control unit
a. Inlet pipe (main drainage pipe)
- The inlet pipe to the lifting station must be designed in accordance with the applicable standards and installed accordingly. All pipes must be laid in such a way that they can drain naturally.
- The pipes must not be constricted in the direction of flow.
- Changes in direction of main or collection pipes must only be made using bends of ≤ 45°.
- Transitions to larger nominal sizes must be made using transition fittings or other suitable connections (e.g. transition seals). In collector connection pipes, eccentric transition fittings should be installed with the centres aligned. To facilitate inspection, installation in main drainage pipes must be flush with the pipe bed.
The pressure pipe connection is made of PE DN 80 (OD=90 mm).
KESSEL recommends using standard PE-HD electrofusion sockets.
Alternatively, the pressure pipe can also be connected using standard Clamp connectors
(see KESSEL accessories, item nos. 28090/28091/28092).
b. Pressure pipe
1. The following also applies to pumping stations located outside the building: the pressure pipe must be routed above the backwater level, in line with the base of the backwater loop. The non-return flap does not serve as backwater protection; its sole purpose is to prevent wastewater that has already been pumped from flowing back into the pump tank. The following options are available for routing the pressure pipe above the backwater level in outdoor installations:
- lead it back into the building
- into an outbuilding (garage, tool shed, etc.)
- into an outdoor cabinet (see below)
- into an earth embankment (with earth cover in accordance with climatic conditions)
If pipes are installed in areas at risk of frost, e.g. in garages, the pressure pipe must be protected against frost.
2. Pressure pipes laid in the ground must be suitable for this purpose. Pressure pipes made of PE-HD or PVC are used here
c. Ventilation pipe
To safely vent the gases that form in the tanks of the lifting stations, each station requires adequate aeration and ventilation. In addition, the negative pressure in the tank, which can arise during the pumping process, must be equalised.
a. In the case of underground pumping stations, the ventilation pipe is connected directly to the tank. Depending on the type of system, either direct connections or drilling surfaces are provided for this purpose.
b. The ventilation pipe can be installed in the following version:
- as a separate pipe above the roof
- as auxiliary or secondary ventilation over the roof
- parallel to an external downpipe over the roof
- with a vent cap on the property
When ventilating the pumping station, care must be taken to ensure that the escaping gases do not cause any nuisance to residents. A sufficient distance from windows, doors and neighbouring properties must be maintained.
c. Ventilation pipes are exposed to the ground and must be suitable for this purpose. Therefore, a standard KG or KG2000 pipe is used here. The smallest size available is DN 100. Consequently, the ventilation pipe is laid in the ground as DN 100. Later, inside the building, the ventilation pipe can be continued using an HT pipe (or similar) with a minimum diameter of DN 70.
d. Cable duct
a. In the case of pumping stations, the cable duct is connected directly to the tank in the ground. Depending on the system type, direct connections or drilling surfaces are provided for this purpose.
b. It must be laid with a slight gradient (we recommend 1–2%) towards the lifting station so that any condensation can drain away and the cables are not permanently submerged in water.
c. Cable ducts are exposed to the ground and must be suitable for this purpose. Therefore, a standard KG or KG2000 pipe is used here. The smallest available size is DN 100. Consequently, the cable duct is laid in the ground in DN 100.
e. Location of the control unit
For pumping stations located outside the building, the planning of the electrical system and the control unit is particularly important. As a rule, there are two scenarios here.
a. If the pumping station is located in the immediate vicinity of the building, the cable duct can be routed into the building to house the electrical system there. A plant room is often suitable for this purpose. If it is to be positioned in generally accessible areas, it is important that it is protected against unauthorised access. Furthermore, the cable duct must be provided with a proper waterproofing layer to prevent the ingress of moisture or pests.
b. For maintenance purposes and to reduce planning effort, the control unit is often housed in external outdoor cabinets. In this case, the control unit is located near the pumping station so that it can be accessed directly for maintenance. The cable duct is routed from the pumping station directly to the outdoor cabinet.
outdoor cabinet
Outdoor cabinets are very often used for underground pumping stations, as they simplify installation and planning. The control unit and backwater loop can be housed in a single outdoor cabinet. The outdoor cabinet is supplied with power centrally from the building. A power supply must be provided for this purpose. The outdoor cabinet houses the control unit for the lifting station as well as a frost monitor to protect the pressure pipe.
Outdoor cabinets usually have a separate warning beacon. Nevertheless, when planning, consideration must be given to how a fault signal can best be relayed. Optionally, fault signals can be relayed via SMS using the KESSEL GSM modem TeleControl.
