Reducing waste by design

Designing out waste is a concept that can apply to any engineering and architectural discipline. The construction industry produces over 70 million tonnes of waste each year₁, and building services in particular has the potential to generate high value wastes.

Waste minimisation is any technique that either avoids, eliminates or reduces waste at its source₂. Designing out waste is the best approach to the problem, particularly for hazardous waste. It is much better to manage the process so that there is little or no physical waste to manage. This is obviously very difficult, but the concept of designing out waste begins with the question: can the amount of waste being produced be minimised, if not eliminated?

Over the last two years research at Loughborough University in collaboration with AMEC has focussed on designing out waste and particularly the decisions and practices in design that create physical waste on site₃. The research is part of a £850 000 Integrated Collaborative Design Project funded by EPSRC, DETR and a group of twelve industrial partners^*.

For years, the construction industry has considered waste as a necessary, unavoidable cost. Following the introduction of the landfill tax, and its spiralling charges which will reach £15/tonne in 2004 for mixed wastes, many companies have reviewed their waste disposal costs and how they could be reduced.

The industry started investing in waste management approaches that broadly followed the wastes hierarchy. Within this hierarchy (figure 1, overleaf), waste minimisation has the highest priority followed by reuse and finally disposal, for example as landfill. To date, though, the much of the industry's effort has focussed on lower priorities, namely reuse and recycling.

So while traditional routes of waste disposal are being abandoned in favour of more sustainable waste management strategies, most construction firms have placed waste reduction at the bottom of their research agendas. This is largely due to the complexities of reuse and recycling.

This approach does not offer the greatest long-term benefits, as it fails to address the causative issues of waste generation where the greatest environmental and cost benefits can be found. In other words, the industry is avoiding "end of pipe" solutions.

The research findings
Seven AMEC sites have been audited with the objective of retrieving quantitative data on volumes and types of waste. The sites were selected to represent a selection of industrial and commercial buildings that included a broad range of complex services packages.

The data is complemented by interviews with site personnel to identify why wastes arise. The wastes data is then reviewed to construct waste profiles per works package. This information is then used to help construct a process map that helps track the waste back up the design and construction process to identify the cause.

Decisions are made at each stage of the design and construction process which indirectly, or directly, create physical wastes. Such waste not only includes high value direct material wastage such as ductwork and cabling, but also indirect 'secondary' wastage such as packaging.

Wastes from building services and other specialist packages arise for a number of reasons:

• materials and component complexity
  
• building complexity
  
• co-ordination
  
• fast tracking
  
• communication

The use of fewer materials in design adds environmental value by reducing the number of waste streams both at source, particularly during the construction process and during demolition. While fitness-for-purpose and improved energy efficiency are essential, the wide ranging materials often result in a specific-for-purpose approach which contributes to bespoke design and less materials reuse on site.

In terms of building complexity, while the increasing number of specialists in the design process has improved building environments, it is also likely that waste has increased. Furthermore, building elements are often designed in isolation, and the quality of information that passes between contractors is highly variable and open to misinterpretation.

This co-ordination issue is confirmed by Womack and Jones4 who suggest the identification of the root cause of 'muda' (muda: any human activity which absorbs resources but creates no value) will come from analysing all the specific actions required to produce specific products, like buildings and building systems. This will identify all the interactions, as well as the characteristics of the individual activities.

Fast tracking can lead to innovation. It can also stifle attempts to design out waste. So often on site, one hears the familiar comments suggesting "if we had time we could have...". It is however, reassuring that many people on site understand that the design process is also often 'squeezed' in terms of time.

Effective communication is vital if waste is to be minimised in design. Delays in design are often expensive, but errors in design lead to errors in construction and waste.

A second issue relating to communication is one of informing the client so that they can make more informed decisions regarding, for example, the environment.

Addressing waste in design
Design decisions ultimately determine the characteristics of a project's waste stream characteristics. The design of a product or system will also determine the route of disposal. For example, whether a material can be separated, recovered or reused.

The application of environmental design into the project process can be distinguished by degrees of innovation, be they product innovations or system innovations. The most innovative approaches would probably question the need for the building, such as the abandonment of building services towards passive strategies like natural ventilation.

Whichever innovative strategy is adopted it is necessary to identify the route of the waste, whether its origins are in concept, scheme or detail design, and what disciplines are involved. A waste reduction strategy is then needed to address the cause (figure 2). Finally, the process of designing out waste must be integrated within the project process. One way of doing this is to integrate it within the value engineering exercise₅.

The future
Building services are a substantial part of a design budget. In addition, they remain all pervading in terms of energy efficiency and building life cycle CO2 emissions, so are at the heart of sustainability.

It would be unwise to conclude that building services should undergo radical redesign or standardisation simply to reduce waste, when clearly the main focus should be on energy conservation. However, the reduction of waste, in terms of materials or time is beneficial to all because a reduction in cost will result in better systems within the same budget.

There is little doubt that initiatives such as pre-assembly and standardisation have waste avoidance spin-offs, but many mainstream players in the industry are not adopting these. Ironically the landfill tax is unlikely to motivate the building services industry as the volume of high value wastes produced is relatively low.

Nevertheless, the reduction of materials, improved flexibility, pre-assembly and correct specification all have an important role in streamlining building services to reduce wastes. Additionally, the more straightforward issues of co-ordination, communication and buildability can have an immediate impact on reducing waste.

The wealth of solutions to address waste created through design reflects the need to understand the reasons why wastes are generated in the first place. Each design decision which is responsible for creating waste needs to be identified through due study. Only then can engineers and architects design out waste.