The striking office building at One Coleman Street impresses with its unique façade. 425 sculptural pre-cast concrete sections contrast with colour-neutral solar control glazing, each pane tilted at a different angle. None of the pre-cast concrete shapes was used more than six times throughout the entire structure. This amazing design is combined with environmentally friendly technology and earned the building a BREEAM rating of "Very good".

• Fly ash used as a substitute for cement
• Use of regional materials (shorter distances for transportation)
• High proportion of recycled building materials
• Intelligent building services system featuring energy monitoring and energy-saving features
• Active use of daylight thanks to extensive use of glass in the heat-insulating façade
• Solar shading including directed daylight
• Workstations with daylight-linked light management system and presence detectors
• Rainwater retention
• Ideally located for commuters to use public transport

Eco-balance
Using fly ash in place of cement in the concrete for One Coleman Street saved some 500 tonnes of CO₂.

Insulation with special heat-conserving glazing and a green roof
The 3,000 square metres of solar control glazing (ipasol neutral 68/37) allow plenty of daylight into the building while preventing the office space from heating up when the sun is strong. The glazing also provides effective heat insulation and stops the space from cooling down on colder days.

The building has a roof garden which fulfils several functions:

• Rainwater retention
• Sound and heat insulation
• Ecological climate control (absorbs dust and pollutants, cools the space below)
• Improvement of microclimate

Bus system technology featuring energy monitoring
Intelligent networking of building services unlocks hidden potential energy savings by planning, running and controlling all systems within the building in an integrated fashion – encompassing heating, power supply, lighting, blinds, climate control, ventilation systems and security systems. All meter information is captured by an optical interface and can be read and processed at a central point.

Daylight-linked light management at workstations
The workstations are equipped with an intelligent light management system. A dimmer control with a sensor integrated into the ceiling analyses the light in the area below and adjusts the lighting level up or down, depending on the amount of daylight available. The dimmer can be activated and deactivated either manually or by means of motion sensors and presence detectors. Implementing daylight-linked lighting at workstations allows electricity savings of up to 75%.

Intelligent water management
Taps featuring sensor technology dispense water for handwashing, thereby minimising water consumption. The building services system also incorporates a smart water meter which facilitates water management through timely and precise analysis of consumption data.

Rainwater retention to relieve the sewers
Rather than flowing straight into the sewer system from roof areas, rainwater is absorbed by vegetation.

Sustainable façade engineering
One Coleman Street is the first major project in London to use fly ash in its concrete exclusively in place of cement. This earned the project the 2007 Concrete Centre Award for Sustainability.

Fly ash in place of cement
Using pulverised fuel ash (PFA, also known as fly ash) as a concrete additive is an extremely efficient way of reducing CO₂ emissions and therefore greenhouse gases. Because pulverised fuel ash is a by-product of generating electricity in coal-fired power stations, no resources are consumed and no open or unspoilt space destroyed in its production. Every cubic metre of eco-concrete saves one tonne of raw materials from being depleted and avoids the need to dispose of one tonne of construction waste.

One Coleman Street shows the way forward
Constructing the façade of One Coleman Street involved close cooperation between the construction team and specialists in new building materials. As a consequence, it was possible to achieve high levels of user comfort and architectural aesthetics using an exceptionally high proportion of recycled building materials. This innovative eco-model has subsequently been applied to other projects.

Climate control and visual comfort on every level
The generous open plan space arrangement and ample glazing create a bright, sophisticated atmosphere featuring abundant daylight. Users have access to controls for temperature, solar shading and lighting to maximise individual comfort.

Outstanding space efficiency
With just two internal concrete columns and a steel frame, One Coleman Street has a remarkably efficient net-to-gross space ratio of 89%. This means that almost 90% of total space is useable.