Balancing the books

Waste neutrality might not get as much press as carbon neutrality but, like its higher-profile cousin, everyone agrees it is a worthy ambition. The trouble is, no one quite knows how it can be achieved on site, or even how it can be measured. And that’s where WRAP comes in. Its construction department, headed by Dr Mike Watson, has devised a simple equation for calculating a project’s performance on waste – and identifying ways to improve it. It is called the net waste method and it goes like this: the value of materials wasted minus the value of reused/recycled materials specified equals net waste (AKA, w-r=z). If net waste is zero, the project has reached waste neutrality.

Hitting zero isn’t the be-all and end-all, however, says Watson. “The point of the method is to get the whole sector, including clients, to consider both sides of the equation. So, they’re looking at the efficient use of materials from the waste perspective, to try to reduce waste, but also at reusing and using materials with recycled content.”

Clearly, this isn’t something you can work out on the back of an envelope on the first day on site. “It’s about starting at a very early stage of planning for waste management,” he says. “In very much the same way as [Defra’s proposed] site waste management plans will require.”

As with the plans, the main contractor will take the lead. But Watson isn't just setting contractors some tough maths homework and leaving them to get on with it. His team is developing a web-based, freely accessible toolkit to measure materials in and materials out, and to help find improvements. To be unveiled in December this year, the toolkit will make the net waste method “relatively painless”, promises Watson.

“Ideally we want construction clients to see the value in this measure of their supply chain performance in a key area of sustainability,” adds WRAP’s David Moon, who has developed the net waste method in consultation with major contractors and suppliers. “Clearly, it will help to identify cost savings almost immediately. The long-term value is using the method to understand how you perform so as to develop business strategies to improve. In many respects this is about business efficiency.”

The way that resources and waste are managed in construction is a huge part of a project. The time and money invested to bring together, use materials and then deal with the left over waste is a considerable portion of the budget. “Any sensible construction client should be keen to discover new ways of improving efficiency,” says Moon. “It is a business issue, not a construction issue. If it adds to sustainability credentials then everyone wins.”

The net waste method will be based in part on WRAP’s existing recycled content toolkit (see page 15), launched in February 2006, which already has 1,000 registered users. This incorporates reference data on the recycled content of building materials, compiled by WRAP and other research bodies. Users input the details of their project and it tots up the percentage that is recycled. Next, the toolkit uses that reference data to spot areas where the project could do better.

“It enables contractors to easily identify the five to 10 top ‘quick wins’ that they can address on a particular project,” says Watson. These big-impact, small effort, changes to the specification could cover anything from bricks to insulation. “A quick win on the recycled content side is something that’s already available, doesn’t add to cost and meets the specification.”

WRAP is now working on the other half of the equation – waste reduction. “We have spent the last year or so with projects gathering the benchmarks to produce the information that would allow us to identify typical wastage rates in different materials on different types of projects,” says Watson. “Data from other organisations that have produced guidance and information on waste and waste arriving on site is used as well.”

When complete, the waste management part of the toolkit will also identify five to 10 quick wins for contractors. “A quick win on the waste management side will be something that does not require a massive change in behaviour. It is something that can be done relatively easily and will make a significant impact without costing more. In fact, on the waste management side, it would lead to a cost saving.”

The tool enables contractors to easily identify the five to 10 top ‘quick wins’ that they can address on a particular project

This hard-nosed focus on cost is at the heart of the net waste method – and it is why the equation is based on the cost of materials bought or wasted, not their volume. “We measure by value because value is the motivator ultimately,” says Watson. “While waste is traditionally measured in tonnage on a site, value provides the key measure for commercial businesses.”

The tool will present the recycled content and waste management data as a balance sheet, so the main contractor can prioritise the changes that have the biggest impact on the bottom line. The costs of waste disposal, such as landfill tax and transport costs, are not included in the basic equation but are calculated by the tool so users have the data.

Of course, the main contractor is not the only commercial business on site – this is a tool for the whole supply chain. “The main contractor needs to work with the designer and specifier,” says Watson. “At the design stage, it’s a case of identifying potential quick wins. When you move on to the detailed design, it’s about refining those to see what is available, what difference that will make.

“With waste management, once the areas to focus on have been identified, the main contractor pushes it onto the relevant subcontractor to make sure they are carrying out the actions.”

Once the project is complete, the entire supply chain can compare the real-life project outcome with the estimated performance on waste, and work out how to do better next time.

To make sure this works in practice, WRAP is trialling the net waste method on eight projects being developed and built by nine big names: Skanska, Bovis, Stanhope, Taylor Woodrow, Carillion, Wates, Balfour Beatty, Crest Nicholson and Willmott Dixon. “The case studies are just kicking off,” says Watson. “With Taylor Woodrow, it’s a housing project. Others are infrastructure. We wanted different kinds of projects. It may be that on certain types of project it’s more difficult to gather the data needed.” He will have the answers by October, when the case studies will be published and fed into the developing web tool.

Once the tool is up and running, WRAP will offer users in-house training, the same kind of bespoke in-house programme already available for the recycled content tool. It is mainly taken up by big companies – “generally large contractors who can put together a significant number of project managers”.

As the number of users rises, WRAP will get closer to its aim: that its net waste method will become the industry standard, giving contractors the data they need to compile site waste management plans or to hit targets for halving waste to landfill.

Ultimately, Watson hopes clients will adopt the method themselves. “That is the route we would like to see this go – a client sets the requirement for net waste to be measured and reduced. How it would work, ideally, is for a client to set that requirement in a tender or in a contract.” At that point, any contractors still not convinced would have no choice but to take notice.