Use the approved project design
This guide explains a typical sequence. It is not a substitute for the chamber manufacturer's instructions, structural design, temporary-works design, risk assessment, electrical design or site-specific engineering.
Excavations can collapse or flood. Pump chambers can float, deform or move if groundwater and backfilling are not controlled. Work must be planned and completed by competent people.
Typical installation sequence
- Confirm the design. Check chamber dimensions, levels, connections, cover loading, groundwater conditions and the specified base and surround.
- Excavate safely. Provide suitable support, access and edge protection. Keep the excavation dry using an engineered dewatering method where required.
- Prepare the base. Place and compact the specified hardcore before forming the approved concrete bed.
- Lower and level the chamber. Use rated lifting points and suitable equipment. Check orientation, inlet level and vertical alignment.
- Control flotation and distortion. Add clean water inside the chamber in stages while placing the specified concrete surround evenly outside it.
- Make pipe and duct connections. Avoid point loads or forced alignment. Seal penetrations using the specified components and support connecting pipework.
- Complete the surround and cover detail. Follow the design for backfill, slab, cover and frame, especially in trafficked areas.
- Install mechanical and electrical equipment. Fit pumps, guide rails, pipework, valves, floats, controls and alarms to the approved drawings.
- Test and commission. Confirm pump rotation where applicable, automatic levels, duty changeover, assist operation, alarms and discharge performance.
Groundwater and flotation
An empty GRP chamber can be buoyant. Groundwater must be controlled during installation, and the chamber must be restrained by the approved base and surround. Filling the chamber internally with clean water in controlled stages helps balance pressure while the external concrete is placed.
Concrete placement
Place the surround evenly and in controlled lifts. Do not pour heavily against one side or allow concrete to free-fall in a way that could move or distort the chamber. The mix, thickness and curing requirements must follow the approved design.
Connections, covers and traffic loads
Pipework should not impose unsupported loads on the chamber wall. Ducts need draw cords, sensible routes and sealed ends. The cover, frame and supporting slab must suit pedestrians, cars or heavier traffic as applicable; loads must not be transferred directly into an unsuitable chamber neck.
Before commissioning
- Remove construction debris and check that the chamber is clean.
- Confirm pumps, chains, guide rails, valves and pipework are secure.
- Verify electrical protection, earthing and control-panel connections.
- Check float or level-sensor positions and free movement.
- Provide sufficient clean water for controlled operational testing.
- Record settings, test results and handover information.