Pipework
110mm Pipework & Fittings
160mm Pipework & Fittings
200mm Pipework & Fittings
250mm Pipework & Fittings
315mm Pipework & Fittings
Twinwall Pipe
Non-Return Valves
MDPE Pipework & Fittings
Linear Drainage
Pipe Carriers
Rubber Pipe Couplings

Conder cesspool installation instructions

IMPORTANT
Please read and understand this entire guide prior the to commencement of installation. This is a generic guide that cannot provide specific, site related, information. If there is doubt about any aspect of your installation, please contact Conder Products Ltd.

SERVICE SPECIFICATION
Check the tank identity label inside the manway turret to ensure that you have the correct type of tank for your installation.
These tanks are designed to be installed below ground and completely surrounded with concrete. Generally, the depth from finished ground level to the top crown of the main shell should be no more than 2 metres. This may vary dependant upon ground water conditions. Deeper inverts may be accomodated on a standard shell providing the water table level does not exceed 2 metres above the top crown of the main shell. For deeper burial with high water table conditions heavy duty shells are available. Should you be in any doubt regarding suitable shell application please call our sales number 0870 264 0004
If the tank is installed outside these parameters it may suffer irreparable damage.

CONCRETE SPECIFICATION
The specification for the concrete mix to surround the tank may be taken from BS 5328 : Part 1 : 1991 (including amendments), taking into account the site conditions and application requirements. For a typical non-structural application in non aggressive soils a Standard Mix ST4 with a 50mm slump is generally suitable, but also permits the equivalent Designated Mix GEN3 to be specified as an alternative. If for non typical applications, structural or other reasons a higher than normal designation is required, the purchaser of the fresh concrete can use table 6 in BS 5328: Part 2: 1991 (amendment 8759/October 1995) for guidance.
Lift height (rate of rise)
Determine the lift height (m), or rate of rise (m/h) for the specific concrete type used, to ensure that a design pressure (P max) of 15kN/m2 on the tank is not exceeded.
Vibration
The design of the tank assumes minimal compaction of the surrounding concrete. Where necessary, this may be extended to include light internal vibration. Never use deep revibration which will substantially increase the pressure on the tank, possibly causing failure.
Impact of Concrete on Discharge
The effects of impact on discharge are considerable. These are controlled by the vertical form height, the tank diameter and the method of discharge.
Under no circumstances should concrete be discharged directly onto the tank.
Loadings
If the tank is installed in an area where traffic or other superimposed loadings can be applied, consult a structural engineer for the design of a reinforced concrete slab to prevent the load being transmitted to the tank (or its concrete surround). If this slab is constructed immediately above the tank, it should be separated from the concrete surrounding the tank by a compressible material.

HANDLING
The contractor is responsible for offloading the tank and any accessories.
The tank should be lifted using webbing. Any chains or steel ropes used in rigging must not be in contact with the tank. Do not lift the tank if it contains any water. Maintain control over the tank when lifting by use of guide ropes. Do not allow the tank to impact against other objects. If the tank is stored on site prior to installation, it must be on flat, level, ground where it cannot be punctured or otherwise damaged. Chock with tyres or other cushioning material to prevent rolling, and tie down if high winds are expected.

GENERAL INSTALLATION PROCEDURE
Installation procedures must be in accordance with the Health and Safety at
Work Act 1974, and other relevant legislation. Your procedures must also align with good building practice.
1 Excavate for the tank, allowing sufficient clearance for the minimum concrete surround thickness as shown in the table below, whilst also taking into account any shoring / trench supports used. The depth of the excavation is determined by the inlet and outlet pipe invert levels relative to the bottom of the tank, and allowing for the minimum base thickness shown. Dimensioned details of the separator can be taken from the relevant drawing. Ground instability at formation level e.g. running sand may necessitate over-excavation and stabilisation with hardcore or blinding concrete.
NOTE: Check that the depth to the base slab is within the
Service Specification requirements for the tank

2 Maintain a completely dry excavation until the final pour of concrete has set. Failure to do this may result in voids beneath the tank and subsequent tank failure.

3 Pour the concrete into the bottom of the excavation to form a level and smooth base onto which the tank can sit. This should be to the minimum thickness given in the table above.

4 Place the tank onto the concrete base, while the concrete is still wet, and determine the correct orientation for the tank inlet(s) and outlet(s), i.e. the higher pipe on the tank is to be connected to your upstream (inlet) pipework, and the lower pipe on the tank is to be connected to your downstream (outlet) pipework. Connect and seal your pipework to the tank, checking alignment, and ensure that there is an adequate and correct fall for each pipe.

5 Fill each chamber of the separator with clean water to a depth of 300mm and recheck the pipework levels. Commence backfilling evenly around the tank with concrete ensuring there are no voids, particularly at the bottom of the tank shell. Continue filling the chambers with water whilst evenly backfilling with concrete ensuring that the progressive water level is no more than 300mm above the concrete level.

NOTE: Never increase the lift height or accelerate the rate of rise for the concrete type used, or allow the concrete to be compacted to an extent which will cause the tank walls to distort. If you contravene this warning you will cause damage to the tank.
6 Connect and seal turret extensions prior to completing the concrete encasement of the main tank to the height shown in the table. Allow this concrete to set.

7 Using appropriate formwork, continue pouring concrete around the tank superstructure (i.e. bypass chamber, access turrets) in lift heights not exceeding 500mm, allowing initial set between each lift.

NOTE: Never increase the lift height or accelerate the rate of rise for the concrete type used, or allow the concrete to be compacted to an extent which will cause any part of the tank superstructure to distort. If you contravene this warning you will cause damage to the tank.

8 Complete backfill to ground level using free flowing material. Trim all access turrets and prepare suitable footings for each manhole frame ensuring that any loads on the covers are not transmitted to the tank access turrets or access extensions, if fitted.

ACCESS EXTENSIONS
Access extensions shall be surrounded with concrete poured in 500mm lifts allowing initial set between each lift. The pressure from concrete placed in higher lifts may cause access extensions to distort or collapse.
Please note that loose shafts should be sealed using silicon sealant sikaflex – 291 or similar prior to installation to prevent ingress of groundwater under high water table conditions. It is the contractors responsibility to ensure a watertight seal.

conder_cesspools_installation_instructions.pdf - 72kb
Download this file