Sheppard Robson’s design for Siemens’ headquarters at MasdarCity has established a new model for sustainable office buildings in the Middle East. It is anticipated to be one of the first buildings in the region to achieve LEED Platinum. The design began with a simple and over-arching ambition: to maximise efficiency and build more with less. An iterative process of traditional design and parametric analysis resulted in an efficient and compact plan form that has reduced material and embodied carbon.

The building envelope was conceived as a box within a box: an inner highly-insulated, airtight facade designed to reduce thermal conductivity, and a lightweight aluminium external shading system which minimises solar gain while maximising daylighting and views from the building.

The office floorplates, each of 4,500m², have been optimised for efficiency, daylight and flexibility using parametric modelling and achieve over 90% efficiency.

In addition to maximising efficiency of all aspects of the built form, the integrated engineering systems have been optimised to complement the building’s function and low carbon design. Rigorous energy modelling has ensured that the building performs 46% better than the baseline ASHRAE energy model.

Siemens Middle East Headquarters was designed from the inside out – led by the ambition to achieve efficiency, rather than a predetermined aesthetic, the resulting building is both commercially successful and environmentally sound: a truly sustainable solution.

1. Design Siemens Middle East Headquarters demonstrates how a biomorphic architectural approach can be applied to the challenge of designing a truly sustainable building in an extreme climate. The methodology developed on this project has considerable potential for application to other projects in the Middle East and beyond.

Process-driven design methodology From the outset of the project, the design team adopted a process-driven design methodology. They rejected a preconceived notion of what the building should look like, and instead set out to investigate and provoke discussion during the design process with all the various members of both the Masdar team and the consultant body in an inclusive and integrated way. The fundamentals that formed this approach can be summarised with the following four words: • Efficiency • Optimisation • Integration • Legibility

The overarching ambition was to evolve a simple building that had been truly optimised for its purpose and context.

A biomorphic design process Natural selection in biology refers to the optimisation of design through the evolutionary interaction with the environment within which an organism exists. Our design process aimed to evolve in a similar organic way by responding to the needs and inputs of its brief. At the outset we interrogated the brief thoroughly in order to fully understand the opportunities that it offered, and we challenged assumptions if we felt that limitations had been set which reduced this potential.

Natural systems are optimised through an evolutionary process. In the development of the Siemens headquarters we measured and tested the efficiency of the various design aspects to evolve the optimum design solutions.

Parametric analysis and traditional design An iterative process of parametric analysis and traditional design tested and retested the efficiency of floorplate layouts, wall to floor ratios, solar incidence on the facade, structural systems and environmental systems. This process harnessed the speed and efficiency of parametric analysis (an algorithm based methodology) while also ensuring the benefit of the design team’s cumulative and considerable experience in office design.

Once the final conceptual design was agreed, the process then began to look at the next level of detail: investigations into how to maximise the efficiency of the cladding design, alongside other areas of study such as column form and service distribution layouts.

At each key stage a fundamental interrogation of individual building elements was undertaken to optimise the solution in isolation before a full integration was carried out to further find efficiencies in design.

It is important to note that this approach is not always aimed at quantifying what can be empirically measured. The social wellbeing of the occupants for example is of fundamental importance to the success of a truly sustainable building, and at all times we aimed to drive the solution towards not only an efficient solution, but also one which is a pleasure to occupy.

Parametric facade design The building envelope was conceived as a box within a box: an inner highly-insulated, airtight facade designed to reduce thermal conductivity, and a lightweight aluminium external shading system which minimises solar gain while maximising daylighting and views from the building.

The variation in the form of the shading systems was designed to offer legibility to the architectural expression with each facade tailored to suit its solar orientation. Delicate, articulate modular components cast intricate shadows on the internal box. As the sun circles the building, shadows animate the interior and give the façade depth. From a distance the building appears as a simple whole, but the individual components become visible and independent as you come closer.

A small number of materials repeatedly appear in the façade, unifying the design without distracting from the striking geometric pattern. Internal window positions are carefully placed to provide consistent internallighting, and atria are fully glazed, welcoming you with light and a feeling of space as you enter the building.

Ultra efficient floorplates The office floorplates, each of 4,500m², have been optimised for efficiency, daylight and flexibility using parametric modelling and achieve over 90% efficiency. They are punctuated by nine atria and served by six perimeter cores.

Completely column-free floorplates incorporate 15m spans by using an innovative post-tensioned flat slab with integrated void-forming technology. This reduces the material used by approximately 60% and provides maximum flexibility for the office space planning. The arrangement enables each of the floors to be subdivided into a combination of various space sizes and therefore creates flexibility for the building to be remodelled over time to accommodate between one and 32 tenants.

Permeable public plaza The office floors float above a fully shaded public plaza which connects the level change between the existing adjacent podium and the more formal square with its Light Rail Transport station. The plaza has been conceived as a terraced extension of the existing public realm and encourages pedestrian movement within the heart of the site. The introverted nature of the shared public realm is further enhanced by a series of external rooms, retail units and two fully glazed office receptions.

Optimised building performance In addition to maximising efficiency of all aspects of the built form, the integrated engineering systems have been optimised to complement the building’s function and low carbon design. Rigorous energy modelling has ensured that the building performs 44% better than the baseline ASHRAE energy model.

6. Sustainability LEED Platinum Energy demand reduction: 65% over typical UAE commercial office - 102.6 kWh/m2/yr Operational carbon reduction: 50% over typical UAE commercial office - 417 kg/yr/m2 On-site renewable provision: 20% Water demand reduction: 60% reduction over typcial UAE commercial office - 6 L/day/m2 Waste diversion to landfill: 62% Materials, embedded carbon reduction: At least 30%

U values: Roofs 0.20 W/m2-K Above-grade walls 0.38 W/m2-K Vertical fenestrations 1.60 W/m2-K SHGC (Social heat Gain Cooefficient): 0.25 Maximum area of glazing: 35% SRI (Solar Reflective Index): minimum 78

The ambition to design a truly sustainable building informed the Siemens Middle East Headquarters project from the outset. The iterative process of traditional design and parametric analysis, combined with a careful balance between form, function, cost and environmental impact, resulted in an efficient and compact form that has reduced material and embodied carbon and that is also commercially successful - a truly sustainable solution.

Design Approach The first priority was to reduce energy demand by fully utilising the building’s fabric, considering embodied and active energy consumption, control and influence and behavioural change through good design. The second priority was to harness natural resources through passive design and careful consideration given to the micro climate. We needed to carefully balance client and end user requirements with a design appropriate to its function, challenge conventional approaches and seek innovative ways of reducing energy consumption. Fundamental to the design approach to this project was the desire to achieve more with less.

Our strategy was to design a legible building which optimises efficiency in sustainable, commercial and social terms that is fully integrated within itself and Masdar City.

Our design ambition was to evolve a simple building that has been truly optimised for its environment by: • Adopting the best Passive Design solutions. • Optimising the Efficiency of the Design. • Integrating technology at a level that is appropriate and usable.

Sustainability Benchmarks To benchmark the design, the proposed building has been designed following the latest set of MASDAR Sustainability KPIs, MASDAR MEDG 03, and benchmarked against the Pearl Rating System for Estidama / Building Rating System Design & Construction / Version 1.0. The project has also been benchmarked against LEED as required by Siemens. Target Ratings: Estidama PBRS 3 Pearls (currently on target to achieve 4 pearls) LEED CS V3.0 Platinum Certified

Climate and comfort Abu Dhabi has a very high temperature range (14°- 24° in winter and 30°- 45° in summer) and relatively high humidity levels (25% - 80% in summer and 40% - 90% in winter). Its monthly temperature and relative humidity averages fall in the following climatic zones: hot-humid, warm-humid, and moderate. Abu Dhabi’s climate is a cooling-dominated climate with negligible heating requirements in the winter. Given its extreme hot humid nature, it will require a combination of several cooling strategies to achieve acceptable comfort levels.

Solar Gain Solar gain in the UAE has a significant impact on the design of buildings and masterplans. For this building, the architecture was derived by considering the external environment and masterplan context. Orientation, form and facade determine the fundamental energy performance of any building. Studying local climate conditions and context we tested designs using advanced building modelling techniques to optimise daylight, facade layering and glazing orientation to minimise solar gain, optimise shading, ventilation to external shaded spaces, thermal transfer and thermal radiance.

Building skin thermal performance As a passive design strategy, within the site constraints the building volume was designed to provide the most efficient wall to floor ratio in order to minimise the external surface and hence the potential for heat gains. The envelope will be highly insulated and air tight to minimize heat gain whilst reducing the requirement for active cooling. Our approach has been to design a clean flush facade minimising the risk of air infiltration through unintentional openings in the building envelope, delivered using an off-site prefabricated unitised cladding system. This simple flush envelope also minimises the collection of dust and sand.

Mechanical cooling Energy modelling of mechanical cooling options showed that the most energy efficient was the fan coil system and this was consequently selected.

Water conservation Water conservation design strategies support the vision of Masdar City, in line with the sustainable One Planet Living Principle (OPL), by striving to reach the goal of ‘achieving a positive impact on local water resources and supply’ and comply with the flow rates defined in Estidama. A range of techniques have been combined to significantly reduce water consumption. These include low usage appliances, low flow valves and fixtures, rainwater capture and storage and low water dependent landscape. As per Masdar’s site-wide infrastructure design guidelines, storm water and grey water will be collected within the building plot and distributed to a decentralized grey water treatment plant to recycle the onsite generated effluent. It is envisaged that black water will be collected and treated separately, to a level suitable for reuse within the site wide city infrastructure.

Renewable energy In accordance with Masdar guidelines no photovoltaics are being provide on the site but solar thermal panels are included for domestic hot water.

Embodied energy For low carbon design the embodied energy of the construction materials can have significant carbon impact. Low embodied energy materials have been specified where possible, considering the ‘whole life carbon footprint’, durability, recycled content and flexibility enabling materials to be recycled at the end of their building life. The design team have aimed at using, where practicable, materials from the Masdar approved materials and the Future Build materials lists.

Materials and finishes Locally sourced durable materials with high recycled content, rapidly renewable content and low VOCs (volatile organic compounds) were specified where possible. The design incorporates void formers in the concrete floor slabs to reduce the material content and embodied energy. All materials were researched and benchmarked against the Estidama PBRS / Stewarding Materials / Liveable Indoors sections as required by Estidama. In addition to the requirements set forth by Estidama PBRS, the building has been ‘Carbon Footprinted’ following Masdar City Embodied Carbon targets.