Wasting away

Being able to deliver an integrated system within the commercial building services sector has become the subject of increasing attention in recent years. With all the advances in technology and a much greater demand that buildings deliver the highest levels of internal comfort to their occupants whilst at the same time exerting as little impact on their local environment as possible – has the need to deliver the ideal M&E solution ever been greater?
Pumping solutions have been part of this evolution with much emphasis being placed on variable speed technology and the energy savings that can be made through choosing e-pumps that combine pump, motor, frequency converter and sensor into one unit – saving on energy, space requirements and in ease of installation.

Building Services Engineers today are taking a more and more holistic view and are delivering a cohesive pump solution that integrates heating, air conditioning and pressure boosting, often within integrated building management systems.

There are still however two application areas that can still be seen as outside of this remit and therefore they are frequently excluded within the final M&E solution – fire protection and wastewater.

Fire protection

Grundfos Fire Systems provide a range of solutions via a burgeoning portfolio that includes a wide range of electric and diesel driven pumps to meet the strenuous requirements of BS5306: Parts 1 & 2, BS EN12845, and more recently NFPA 20.

Packaged fire booster sets need to be built and tested in accordance with the above standards. All Grundfos pumps carry all the necessary approvals (including LPCB – Loss Prevention Certification Board and FM – Factory Mutual). Attaining FM Approval status certifies that industrial and commercial products reach worldwide standards.

Optimum fire protection solutions must not only incorporate a wide range of fire protection equipment with the highest approval levels available, but also be able to ensure that bespoke modifications can be incorporated and that all systems undertake the highest levels of performance testing before placing them on skids and supplying them to end-users.

Grundfos offer a fully customised solution ranging from wet-riser and hydrant packaged pump sets, to containerised packages (within GRP or steel enclosures) – an increasingly popular choice for those customers who wish to minimise the construction and installation required on site, these units provide an ideal solution for commercial building professionals.


The efficient and reliable transportation of sewage and effluent is of huge importance to the well-being and health of the occupants and users of any building. At times of concentrated demand busy commercial buildings such as hotels, residential complexes, theatres and sporting complexes are enormously reliant on effective, dependable wastewater installations.

The Grundfos name may not always have been the first to come to mind in relation to wastewater, but they have been in the business of producing wastewater pumps for over 20 years. Back in 2000, to augment their line-up, they bought the Finnish specialist pump producer Sarlin Pumps. Since then continual investment, expansion and strategic buy-outs have seen this become an area of expertise. Recent product introductions, including heavy-duty submersible sewage and raw water pumps now offer a variety of axial-flow channel-impeller pumps and propeller pumps with motors up to 520kW.

These pumps need to work hard in the toughest of environments where minimum downtime is even more critical than in other more common commercial applications. Therefore selecting a partner like Grundfos that can supply, install and maintain the wastewater solution is critical.

So what types of applications are typically involved in delivering wastewater solutions within commercial premises?

In the main applications fall into three categories: drainage, effluent and sewage.


This is defined as raw water, drainage and untreated wastewater containing solids no larger than 12mm from for example small industrial sites and agricultural applications.

Examples: properties/sites with a basement or cellar generally need an exterior drainage system to prevent moisture causing rot and other serious damage.

Hints: drainpipes should be connected to a drain well or a pump pit fitted with a drainage pump. A minimum free passage of 5-10mm is recommended to prevent clogging. Ideally, the pump should be connected to a level switch or external control system.


This is dirty water and untreated wastewater (excluding toilet discharge) that contains fibres and solids. To avoid clogging, pumps that allow free passage up to 35-45mm are recommended.

Examples: rainwater and other surface water must be drained away from buildings as well as removed in light industrial and laundry type applications.

Hints: it is recommended that pumps with a free passage of 25-25mm are used for the removal of surface water. Level switches or an external control system should be installed.


This is untreated wastewater and raw sewage containing fibres, textiles and other solids, including toilet discharge from domestic and sewage systems, farms and industry. The minimum free passage through the pump has to be at least 50mm. To avoid clogging in commercial buildings, farms and industrial applications a free passage for solids up to 65-80mm are recommended.

Examples: where sewage exists without gravity to move it a system is needed to lift it to another stage to allow its removal. These wastewater systems can be positioned in two different places dependant on the specific need:

1. Inside the Building – the pump station is installed in the basement, collecting and removing wastewater from for example blocks of apartments.

2. Outside the Building – a substation is often used to collect and transfer wastewater from small industrial units etc.

Hints: external applications often need a long pressure pipe and the availability of high pressure. A lifting station is required for installations inside buildings.

These are not all the families of wastewater pumps that are available, but they cover the applications that Building Services Engineers need to consider.

The selection process

Making the best initial pump selection for wastewater applications is even more important than in standard HVAC applications as the potential for clogging, and thereby pump failure if you don’t make the best choice, is very high. Equally selecting a pump that can be easily accessed and readily maintained is again key.

To ensure the optimum selection of pumps are made for each commercial application, opt for a pump manufacturer that has a full-line portfolio and the technical expertise to assist you to design, specify, deliver and maintain the complete pump solution.

To simplify the selection process, Grundfos have just released a new version of WinCAPS CD a Windows based Computer Aided Product Selection tool that also incorporates a comprehensive Wastewater Sizing Guide.

The CD not only contains information on pumps and motor curves; hydraulic and mechanical data; pictures and dimensional drawings but it will also perform a Life Cycle Cost Calculation to allow you to see how much money can be saved by choosing a more efficient pump.

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