Rainwater Management for Residential and Commercial Buildings

Cities are places of diversity. Here, different people, building types and economic sectors come together to form their own cityscape. Newly developed areas meet supermarkets and shopping centres, doctors’ surgeries are built next to office buildings and commercial buildings.

Urban development is also accompanied by new challenges for rainwater management. Due to the expansion and densification of settlements and the resulting increase in land sealing, higher runoff peaks and volumes occur. Central collection or drainage of rainwater is often no longer possible due to the complexity and layout of modern infrastructures. Overloaded sewer networks and increasing heavy rainfall events therefore lead to more and more frequent flooding. The guiding principle of a blue-green infrastructure should therefore not be missing from any planning.

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Requirements for rainwater management in residential and commercial buildings

Several factors come into play when choosing a suitable drainage system for residential and commercial buildings. The interaction of precipitation, water runoff, flooding and building development must be taken into account. In addition, various standards and guidelines for dealing with rainwater must be observed (DWA M-153, DWA A-102, DWA A-138, EN 752 and others). In addition, the regular modernisation and renovation work requires a technically feasible, and at the same time, cost-efficient solution.

Requirements for new residential buildings and areas

Residential buildings are not only a place of retreat and the centre of life for many people, they also shape the cityscape. Therefore, the following requirements must be taken into account when planning the rainwater management of existing residential buildings or new construction areas:

Reliable surface drainage:: The drainage system must be able to reliably collect and drain all precipitation around the residential building. From the terrace to the façade to underground garages and paths.
Infiltrate, evaporate or use rainwater on site:: The goal is to let the precipitation seep away or evaporate on site. Another option is to reuse the water. This promotes smart land use and the efficiency of blue-green infrastructure.
Cleaning rainwater:: Before precipitation can be infiltrated or used, rainwater must be treated. This prevents pollutants from contaminating the soil and groundwater.

Further requirements:

Protection of the building:

The building must be continually protected from precipitation, standing water or pressurised water. Accumulating precipitation must be safely and reliably drained away.

Aesthetic integration with the building concept:

Every building is individual and has its own character, which must be emphasised. The drainage solution must therefore be functionally and aesthetically integrated as part of the building’s architecture and urban environment.

Barrier-free entrances and exits:

To ensure that all living areas are accessible without restriction, passageways and thresholds are increasingly being planned and implemented barrier-free. Of course, the building structure must also be protected from precipitation.

“When planning and implementing drainage solutions for residential & commercial buildings, many requirements must be taken into account. I am happy to support you in all project phases – from the drainage application to the hydraulic calculation and installation.”

Dirk Kimmel Project Manager at HAURATON

Requirements for commercial buildings

Commercial buildings also place high demands on drainage. In addition to safe solutions for heavily trafficked commercial areas, watercourse and groundwater protection also play an important role.

Absorbing loads from heavy vehicles:: The installed system must withstand the high dynamic forces caused by heavy vehicles driving over it.
Drain high volumes of wastewater:: Due to increasing land sealing, rainfall can quickly lead to very high runoff volumes. The drainage system must be able to drain these large amounts of rainwater.
Filtration of pollutants:: In urban areas, rainwater comes into contact with pollutants such as tyre wear and heavy metals. Filtration channels collect the surface water safely and clean it of pollutants at the same time. The water can then be safely infiltrated or discharged into a receiving watercourse.
Longevity & easy maintenance:: The installed channels must have a long service life. Maintenance and servicing should be able to take place during operation.

Solutions for comprehensive rainwater management for residential and commercial buildings

There are two different solutions with various possible combinations for planning a comprehensive rainwater management concept for residential and commercial buildings.

High-performance channel systems for maximum traffic safety up to load class F 900 according to EN 1433.

Combination option A: Green swale
A revitalised soil zone allows large amounts of water to be collected, temporarily stored and infiltrated. Pollutants are bound in the soil. Disadvantage: Large space requirement, high maintenance effort, little control over the cleaning performance and heavily polluted soil.
Combination option B: Green swale with technical filter
By inserting a technical filter into the green swale, the water can be efficiently pre-cleansed. The maximum 30 cm high filter layer in the swale retains the pollutants on the surface and the swale can be made significantly smaller. In addition, it requires less maintenance.

Heavy-duty drainage channel with filter substrate integrated into the traffic surface is installed at the end of the parking row or between two parking spaces. This creates a visual separation and can still be driven over and walked on.

Combination option C: Tree pit
Rainwater from traffic areas can be used, among other things, to irrigate tree pits. Due to the pre-cleansing in the filter substrate channel, the rainwater can be fed directly to the plants.
Combination option D: Infiltration elements
In combination with the DRAINFIX BLOC 300, the pre-cleansed water can seep into the ground. Due to the possible retention volume in the channel, the volume of the infiltration element can be smaller than that of other systems.
Combination option E: Infiltration elements for retention
Pre-treatment of rainwater ensures that it can be easily stored and reused.

Product comparison for residential and commercial buildings

DACHFIX STEEL

FASERFIX KS

FASERFIX SUPER

DRAINFIX CLEAN

Standard and regulation-compliant drainage for façades, flat roofs, balconies and roof terraces

Efficient drainage channel for commercial areas with car, lorry and pedestrian traffic

Robust drainage system for commercial areas with extreme loads due to heavy traffic

Rainwater treatment through filter substrate channel – system for all types of traffic areas

More about DACHFIX STEEL

More about FASERFIX KS

More about FASERFIX SUPER

More about DRAINFIX CLEAN

Load class according to EN 1433

A 15

up to F 900

Load frequency

–

Load dynamics

–

Nominal width | System size

115, 135, 155, 205, 255

NW 100 – 300

NW 100 – 500

NW 200-500

Materials of the lower parts

Galvanised or stainless steel

Fibre-reinforced concrete

Fibre-reinforced concrete or polypropylene (PP)

Angle housing

–

Galvanised or stainless steel angle housing with 20 x 20 mm insertion depth

Galvanised steel or ductile iron angle housing with 40 x 40 mm insertion depth

Depending on the variant, with FASERFIX or RECYFIX:
Galvanised steel or ductile iron angle housing with 40 x 40 mm insertion depth

Grating variants

– Slotted gratings
– FIBRETEC design slotted gratings
– Mesh gratings
– Longitudinal gratings
– Perforated gratings
⇒ Made of recycled composite, galvanised or stainless steel

– Reinforced slotted gratings
– FIBRETEC and METROPOLIS design slotted gratings
– Perforated gratings
– Longitudinal gratings
– Mesh gratings
– Ductile iron gratings
⇒ Made of ductile iron, recycled composite, galvanised or stainless steel

– Ductile iron slotted gratings
– GUGI ductile iron mesh gratings

Special characteristics

– Design in accordance with standards & guidelines
– Practical height adjustment
– Channel in shallow design possible
– Simple drainage connection through perforation in the channel bottom
– On-site connection continuously protects buildings from standing or pressurised water
– Barrier-free passageways

– Boltless locking system SIDE-LOCK
– 10-fold fixation of the grating per metre
– Extra thick side walls

– Boltless locking system SIDE-LOCK
– 16-fold fixation of the grating per metre
– Factory-made cross and T elements possible

– Rainwater treatment through surface filtration
– Large retention volume
– DIBt approval Z-84.2-7
– DWA-A 102: 97% efficiency
– DWA-M 153: efficiency D=0.06

There are many special features to consider when planning and implementing residential and commercial buildings. We find the right product for every application and support you with our expertise!

Technical experts support you with your project

We are happy to support you as an expert for complete solutions in your residential and commercial building project. In addition to the hydraulic calculation, planning and the implementation of a suitable drainage solution, we also offer customised tailored solutions.