SHOWCASING ALMELO CITY HALL
BREEAM EXCELLENT! As part of a larger plan to revitalise the city centre of Almelo, the newly built city hall is an example of sustainable construction and modern design. With sustainability as the cornerstone of its design, the building is currently one of the most energy efficient public buildings in the Netherlands. The building will receive its BREEAM-NL Excellent certification later this year. City Hall Almelo is an interesting example, as it shows that highly sustainable buildings are achievable with current technologies and under very tight budgets.
OCTOBER 2015 / ISSUE 2
Colophon Eurbanlab Showcasing - Volume 1, Issue 2, October 2015 This is a publication of Eurbanlab in cooperation with Javelin Creative Solutions. Copyright ÂŠ 2015 Eurbanlab All rights reserved. Text: Roger Toussaint, Javelin Creative Solutions Final editing & design: Eurbanlab Graphic design: Joep van Urk, Digital imagine Photography: Stijn Poelstra Client: Kraaijvanger Architecten For more information please visit our website: www.eurbanlab.eu. To submit material for consideration of publication, please contact us at: firstname.lastname@example.org. Every effort has been made to contact copyright holders and to ensure that all the information presented is correct. Some of the facts in this volume may be subject to debate or dispute. If proper copyright acknowledgment has not been made, or for clarifications and corrections, please contact the publisher and we will correct the information in future publications.
Almelo City Hall
Designed for BREEAM-NL Excellent on a tight budget TEXT: ROGER TOUSSAINT
The ambition for Almelo City Hall was clear from the start. Designed by Kraaijvanger Architects, the building was to become one of the most sustainable public buildings in the Netherlands. Together with a sober and pragmatic budget, the ambition for BREEAM-NL Excellent certification represented an interesting challenge for the developing parties. The newly built city hall opened its doors in the spring of 2015. It marks the start of a larger development plan to revitalize the city centre of Almelo. City Hall Almelo is approximately fifty meters high, and consists of a three-story plinth and two connected towers. With a gross floor area of 20.000m2, the building provides in 500 flexible workplaces and 100 parking spaces. The old city hall was built in the 1960s and was in serious need of an upgrade. The municipality of Almelo envisioned a more sustainable, comfortable, inspiring and healthy working environment. At the time, the most sustainable public building in the Netherlands had a BREEAM ‘Very good’ rating. In their statement of requirements, the municipal
council demanded a more ambitious level of sustainability for the renovation of the building: BREEAM-NL Excellent. When project architect Vincent van der Meulen, came on board at the start of the project, the sustainability ambition was not his only challenge. “For a large, sustainable and newly build city hall, the €1300/m2 construction budget can be compared to the budget of a primary school”, Van der Meulen explains. It was clear that the budget and the structural integrity of the old city hall, would not easily allow this level of sustainability to be reached.
Location Almelo, the Netherlands Status Completed Timeline Design 2008 Construction 2013 In-use 2015 Total investment cost €57 million Surface area 20.409 m2 Certification BREEAM-NL Excellent Client Municipality of Almelo Developing parties Kraaijvanger Architects ABC Nova DGMR Valstar Simonis Koopmans & J.P. van Eesteren
Designed together - from scratch Key to the development of a sustainable and cost-efficient city hall was the design approach taken at the very start of the project. In the open tender procedure, Kraaijvanger Architects did not present the client with a ready-made design for the building. Instead, a plan was presented in which the vision and principles were explained. “It was by no measure a finished design that is normally presented to the client. Presenting a comprehensive design means that you are then committed to build that design, even if it becomes clear in later stages that certain choices are less optimal for the sustainability ambition”.
With an integrated design process, project team members from all disciplines are brought together to work together early and often to design a whole building system, as opposed to the traditional silo approach where each stakeholder is only responsible for their own scope. “When we were awarded the tender and first sat together with the client and the design and construction team, there wasn’t a pencil stroke on paper. It allowed us to come up with solutions that made the building more cost-effective, which in turn generated more room for sustainability solutions”.
“When we first sat together with the client and the design and construction team, there wasn’t a pencil stroke on paper”.
In an intensive one-week design workshop, the developing parties worked together on a design that was holistic, sustainable and cost-efficient. Not only the consultants and working groups were involved in this process. Other stakeholders such as local companies and residents were also invited to provide their input. “By doing so, we were able to make an holistic design that was widely supported by the stakeholders”, Van der Meulen explains.
The architect decided to deviate from this standard approach, in order to start an integrated design process (IDP) that would provide room for innovation through increased collaboration.
“The north-facing window surface is increased to make optimal use of the sun’s warmth”
Almelo City Hall Designed to be comfortable & sustainable City Hall Almelo was built on a new square near the waterfront in a green environment. All representative functions are situated in the low-rise section of the building to create an open and inviting feeling for visitors. A wide staircase leads to the council chamber on the first floor, where large windows provide a panoramic view of the surroundings. The offices are located in the towers, arranged around a large atrium that functions as a communal open space. Split-level floors were created to facilitate easy collaboration between employees and the open feeling of the building. The parking deck is situated on the roof of the low-rise section of the city hall. The approach for City Hall Almelo was to make sustainability measurable through BREEAM and to focus on existing technologies, instead of envisioning a highly innovative project with uncertain outcomes. By incorporating a common-sense approach and some inventive design measures to make the building more cost-effective, the developing parties were able to construct a building that meets the municipality’s requirements.
“The building has a compact design and makes optimal use of natural daylight.” In order to achieve a BREEAM Excellent rating, the building had to be designed in such a way that the structure itself would help to reduce energy demand.
“The building has a compact design and makes optimal use of natural daylight. A recurrent problem in offices is overheating, which requires additional cooling”, Van der Meulen explains. “Therefore, the north-facing windows are enlarged, whilst the south-facing window surface is reduced”.
“Visitors of the building will find that the lights are off most of the time because there is enough natural light.”
To further reduce energy demand, LED-lights and daylight sensors are installed, saving approximately 100.000kWh of electricity per year. “Visitors of the building will find that the lights are off most of the time because there is enough natural light”. The recessed high-rise section of the building acts as a passive solar measure for the ground floor, and prevents fall winds at the same time. Energy demand for heating and cooling is further reduced with extensive insulation measures. The façade of the building has an Rc-value of 5 (m2K/W) and all windows are triple-glazed with a U-value of 1,1 (W/m2K). An Aquifer Thermal Energy Storage system (ATES), combined with concrete core activation (CCA) and heat pumps, provide the building with a sustainable system for heating and cooling.
According to Van der Meulen, “the ATES-system is unique to the region of Almelo, because its complex soil structure only rarely allows the application of such systems”. The ATES-system uses thermal energy, stored in the subsurface, to control the temperature in the building. The CCA system circulates hot or cold water through a tube system that is integrated in the concrete floor slabs. As the water flows though the system, heat or cold is transferred to the large surface of the concrete slabs. Unfortunately, the building produces only a limited amount of renewable energy. About 20m2 of solar cells were installed on the roof, but that is hardly sufficient for the city hall. There are plans to expand the number of solar cells in the future. In the meantime, City Hall Almelo purchases 100% sustainable energy from the grid. The combined sustainability measures have reduced the primary energy demand of City Hall Almelo by 80% when compared to conventional office buildings. Compared to a conventional heating system, the ATES system is expected to reduce CO2 emissions by 17% on a yearly basis.
“Compared to conventional office buildings, City Hall Almelo reduced its primary energy demand for heating & cooling by 80%.” In order to build a compact city hall that would (1) further reduce the construction costs and (2) reduce the amount of construction materials needed, some inventive design measures were implemented. A smart integrated flooring system provides a flexible space for the necessary installations. “This means that for piping and construction, only 60 centimetres of space per floor was needed, whereas the standard is 90 centimetres.
In total this saves almost an entire floor’s worth of construction materials”, Van der Meulen clarifies.
“Nearly 95% of all waste generated during construction, was separated in different waste streams and offered for recycling.” The concrete floors are furthermore lined with hollow segments to further reduce the use of concrete. FSCcertified wood was used as much as possible in the structure of the building. A nearby timber frame factory supplied the site with FSC-certified wood. Moreover, a number of Cradle-to-Cradle materials were used in the building. “Where suppliers were not yet certified, but their materials were sustainable, we would encourage them to have their products certified”. The ventilation system uses the natural airflow of the building, eliminating the need for any return-channels in the building. Clean air is pumped through the floors of each level. The upward motion of the airflow in the large central atrium that connects the two towers, extracts the used air from each level. At the top of the atrium residual heat from the air is extracted and recycled. Next to reducing construction materials, nearly 95% of all waste generated during construction, was separated in different waste streams and offered for recycling. A portion of the construction debris was used to create a so-called ‘brown roof’. The 1100m2 flat roof of the car park was covered with a layer of construction debris in order to mitigate the loss of habitation in the city. The roof, with small ponds and beehives, now serves as an ecosystem for a variety of species of plant and animals.
Lessons learned Construction typically involves the translation of designs into reality. In the classical development process, the architect is employed by the property owner and makes the drawings and specifications of the building. Once the design is completed, a construction company - usually the most cost efficient bidder - is asked to realise the plans. “In order to fundamentally increase the sustainability of the new city hall, it was crucial to adopt a more flexible and integrated design approach from the very start of the project”. This process allowed the parties to design the new building together from scratch, thereby developing and adopting integrated solutions by exploiting the insights and solutions from the different stakeholders. “If sustainability is to be a fundamental cornerstone, we cannot approach it as an end-of-pipe solution”. Van der Meulen emphasises that the holistic design for City Hall Almelo and its BREEAM ‘Excellent’ rating would not have been possible without the integrated design process.
“The building can be converted into a housing complex if needed, but another function that requires extra ceiling height will be very difficult to achieve”. Although the developing parties are proud to have achieved this level of sustainability under a very tight budget, Van der Meulen also recognizes the need for a larger and dedicated sustainability budget. “It is good to have shown that a cost-effective and sustainable building is feasible. In the future I would like to build cost-effectively, but with a bigger budget for long-term sustainability measures. Almelo City Hall could have been designed more flexible to allow other functions in the future. The building can be converted into a housing
complex if needed, but another function that requires extra ceiling height will be very difficult to achieve”. Relatedly, developing parties should sometimes actively lobby for a certain topic or measure that would benefit the sustainability of the building, but not necessarily fits in the budget or plan. “Unfortunately, the budget didn’t allow us to do more in terms of water retention or re-use”, Van der Meulen recalls. “The brown roof collects and uses water, but the rest is discharged to the sewerage system. In hindsight, we might have reached BREEAM-NL ‘Outstanding’ certification if we increased the amount of solar energy, or implemented a separate system to collect and re-use rainwater”. Next to the need for an integrated design process and a certain amount of flexibility, the architects explain that it is also important to commit to an ambitious sustainability target and certification scheme. “By committing to a certain certification scheme, all parties know that the project is going to be assessed at some point. This provides an additional motivation to implement effective and integrated sustainability solutions. A certification scheme such as BREEAM assists the market in that”.
“A team that is motivated and inspired to work towards a high level of sustainability is very important.” However, Van der Meulen underlines that certification shouldn’t become a checklist exercise. “Developing parties have to be conscious of the type of solutions that work in the local context and how they affect the sustainability of the building, not necessarily the certification scheme. Similarly, parties should remain open for opportunities to go beyond the requirements of a certification scheme. Having a team that is motivated and inspired to work towards a high level of sustainability is very important. Fortunately, we were able to bring together such a team.” < 10
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Published on Feb 4, 2016
The ambition for the new City Hall of Almelo was clear from the start: BREEAM-NL Excellent. Together with the sober and practical budget, th...