Why are so few buildings genuinely sustainable? The basic principles are very straightforward; minimise artificial lighting, heating and mechanical ventilation, avoid air-conditioning, conserve water, use the site and materials wisely and recycle where possible. But poor design too often results in buildings having an unnecessarily high environmental impact, says BRE Environment’s David Strong.

A fundamental requirement for success is to establish a clear client brief which places the sustainability targets in terms of importance alongside style, image and aesthetics. Putting sustainability at the core of the design brief helps to ensure that the building will be more economic, comfortable, productive, humane and more beautiful than a conventional building.

Delivering sustainable buildings requires a new design vocabulary. In particular climate responsive buildings which are based upon the principles of bioclimatic design requires the architect and engineers to work as an inter-disciplinary team.

This will deliver intelligent buildings which work with natural systems to provide (for free) much of the requirement for lighting, heating, cooling and ventilation.

Holistic design

Integrating the design process enables a “whole system” approach to be adopted. This approach often results in major capital and operational cost savings by “tunnelling through the cost barrier” (see Natural Capitalism, Lovins).

Also, substantial savings in the cost of building services equipment can be achieved by intelligent façade design and by optimising the use of free cooling, natural ventilation and by limiting summer-time overheating, (whilst also maximising daylight and useful solar heating in the winter).

These often conflicting design requirements can only be resolved through integrated design from day one of the design process. It’s essential that the architectural concept is challenged, improved and refined in an iterative manner, with climate responsive design solutions being incorporated as an integral part of the design.

Avoiding greenwash

Green design should be the starting point and never simply addressed by “bolting-on” tokenistic features. Greenwash applied to the building by a marketing or PR department is no substitute for buildings whose designers have addressed the environmental, ecological and energy issues at every stage of the design process.

The true credentials of a green-washed building will become immediately apparent if subjected to a BREEAM assessment and/or if an energy performance certificate is produced.

Increasingly, mandatory requirements for labelling and certification will result in buildings being assessed and differentiated in terms of their environmental and energy performance.

Performance rating and ranking coupled with the growing reporting requirements associated with corporate social responsibility are likely to have a profound effect (both positive and negative) on the asset value of buildings. In short, no organisation concerned about its brand equity or corporate positioning will want to occupy a badly rated building.
Integrated design places the engineer (and ideally the contractor and facilities manager) alongside the architect as equal partners in the design process. Sometimes egos can get in the way of this vital engagement and expert facilitation may be required to deliver the optimum design solution (see Using Design Charrettes to Deliver Demonstrably better buildings).

Designing for whole-life performance

The integrated whole-building design process should also consider the impact in terms of the “whole-life” performance of the building.

For example, increasing the façade from double to triple glazing may save operational energy but the embodied energy, used to manufacture the glass will increase.

These complex trade-offs can be assessed by using Life-Cycle-Analysis (LCA) methods. Software tools such as ENVEST are available to assist the design team to ensure that rational and informed design decisions are made on the basis of environmental impact over the life of the building.

Incentivising the design team

Current professional fee structures do not help deliver low environmental impact buildings. In particular, fees for architects and/or building services engineers which are based on a percentage of the total construction cost (or building services cost) are not helpful.

An engineer who invests extra design time in working with the architect to deliver highly innovate ways of reducing the operational energy cost associated with heating, lighting, ventilation and cooling will be penalised by receiving a lower fee.

This peverse incentive is a major barrier in delivering lower environmental impact buildings. Other fee structures should be used – ideally based on a fixed fee with an incentive element linked to the actual buildings performance over the first seven to 10 years of operation.

This has the added benefit that the design team remains motivated and incentivised to ensure that the building is correctly commissioned, operated and maintained in accordance with the original design intent.

Fee structures of this type have been trialled in the US and have delivered demonstrably better buildings, often at substantially lower cost.

Designing for people

An over-arching objective of integrated sustainable design is to deliver buildings which are healthy, comfortable and productive.

For example, an award winning ultra-low energy school fails in terms of sustainability if the acoustic environment provides classrooms where the learning outcomes are poor. Recent US studies have shown that well designed climate responsive buildings can increase productivity by from six to 15%.

Since most employers spend considerably more on salaries than they do on energy, this represents an even more attractive benefit than the savings on their fuel bills.

High quality sustainable buildings have a profound and well documented impact on productivity in workplaces, learning outcomes in schools, recovery times in hospitals and sales performance in shops (see Greening the Building and the Bottom Line, Romm and Browning, Rocky Mountain Institute).

The challenge of “green” design

Delivering sustainable architecture using climate adaptive/responsive buildings is much more challenging than designing traditional highly serviced climate-excluding buildings.

Conventional buildings using energy intensive electro-mechanical systems to provide comfortable conditions to “fix” a badly designed building is the antithesis of intelligent sustainable design.

Much greater care is also required during construction, commissioning and operation to deliver optimum performance from a climate responsive building. For this reason key design and specification decisions should always be undertaken by a fully integrated multi-disciplinary team. This will deliver intelligent, innovative, and inspired buildings having the lowest possible environmental impact.

In summary, there is nothing stylistically prescriptive about sustainable design. It does however require close collaboration between all members of the design team from the early stages of a project.

Even in hostile climatic conditions buildings can be designed to exploit the natural systems available for free to provide some or all of the ventilation, cooling, heating and daylighting.

Prof. David Strong
Managing director
BRE Environment

Using design charrettes to deliver demonstrably better buildings

The Charrette is changing the way buildings are planned and delivered. Used by some of the UK’s leading clients and developers, the process is promoting intelligent architecture, integrated design and innovative solutions.

The Charette brings client, design team and key stakeholders together at the start of a project to consider a variety of design options and create a plan that meets the needs of all parties.

It involves intensive facilitated discussions during which opportunities are identified to reduce waste and environmental impact, increase efficiency and performance, and to raise the comfort levels and productivity of occupants.

The benefits that accrue from this approach are considerable. They support both commercial and community interests.

• Clients – better buildings, lower construction and whole life costs, reduced risk.
  
• Communities – greater consultation, more inclusion, less disruption.
  
• Design teams – fewer reworks, easier passage through planning, improved reputation.
  
• Occupants – secure, healthy, comfortable and productive environments.
  
• The environment - increased use of renewable resources, reduced waste and pollution, improved energy and water efficiency.
  

The Charrette process starts as soon as the initial decision to procure has been taken. An expert facilitator meets with the client or developer to discuss the broad requirements of the project and draft a brief. Once this has been done, a series of expertly facilitated interdisciplinary meetings with the client, design team and stakeholders are undertaken during which ideas are discussed, options debated, trade offs agreed and targets set.

This process inspires and fuels ideas. By involving key parties in this way and drawing on specialist advice, radical improvements can be achieved during the design and masterplanning process. Greater understanding and commitment develops, fresh approaches are taken, and better solutions evolve.

Learning from Experience

Once a project is completed and the building occupied, BRE recommends carrying out a post-occupancy review to see how well the designs are working. Performance issues are assessed and occupant and user views sought.

This valuable information is analysed and fed back to both client and design teams to inform future projects.