Solving a drainage problem

INTRODUCTION

We were called by our customer, a third-party plumbing and drainage company, to attend a flooded basement at a commercial building in central London.

The building is managed by a national facilities management company on behalf of their client.

On arrival we discovered the large basement was flooded to a depth of four feet. There were two pumping stations in the basement, one foul and one groundwater. Both had failed.

METHOD

To investigate the problem, we first had to remove the flood water. Due to the volume to be removed, we installed an overpumping rig and dewatered for 48 hours. After reducing the depth of the water, we tankered the remainder and jetted the equipment using our 18-tonne combi-tanker. This allowed our pump engineers to inspect the pumping systems.

Both pumping stations had to be replaced. We specified suitable replacements and provided a quotation to the client.

Our investigation also highlighted that there is a steady ingress of water into the basement at the junction of the wall and floor. The basement is 10 metres below ground level. Further investigation is required by the building’s owner to find the source of this water, but it may be due to a nearby water mains pipe leak.

Once the order was placed, our pump engineers attended site to install the equipment. Before work could begin the basement, which was again under 4 feet of water, was dewatered using over pumps. Our 18-tonne tanker accompanied the pump engineers to remove the last of the water and to again clean the basement so that the pump engineers could work.

The replacement groundwater pumping system, comprised a twin submersible pump station with a 10-hour changeover timer panel. The benefits of the panel are threefold. Firstly, it ensures even wear on the pumps so that the system will last longer. Secondly, it features an audible and visual high level alarm. And lastly, its volt free output enables integration into the building’s BMS, so that the status of the pumping station can be monitored remotely – a feature the previous system lacked.

The replacement foul station was a Jung-Pumpen Compli floor mounted pumping station with twin macerating pumps. This model was specified by considering the narrow discharge pipework and the available power supply being single phase only. The floor mounted pumping station was installed into the existing dry well in the floor of the basement.

As this will be a natural sink for groundwater, we also installed a submersible groundwater pump with low level float, which discharges into the foul chamber. This will prevent the foul station sitting in water which may in the long-term cause damage. In normal circumstances this would be a belts-and-braces contingency but is necessary in this instance considering the constant inflow of groundwater.

We installed new PVC discharge pipework, complete with non-return valve, gate valve and dismantling joint for easy maintenance. We supported the discharge pipework by installing unistrut-mounted munsen rings.

RESOLUTION

The pumping stations, which were suitably specified and expertly installed, are operating well. The inflowing groundwater is being managed, whilst a solution is found. The building’s BMS system will now be alerted should a fault in the groundwater pumping station or a high-level condition be detected.

The failed foul water pumping station.

Several night time attendances were required.

The new foul station with groundwater pump and unistrut supported discharge pipework.

FOCUS ON

A complete pumped and drainage capability

This complex project illustrates the breadth of capability that Edincare can employ on behalf of our customers – from site investigation, project design and fault finding, through to drainage services, installations and refurbishments.

Through more than 25 years of delivering exceptional levels of service to our clients, we have earned a reputation for expertise, reliability, and trust within the pumped and drainage industry.

If you have a pump or drainage emergency or are seeking a reliable and expert service partner call 01442 211554.