Reducing construction waste saves money Bridge Learning Campus, Bristol Contractor: Skanska

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1 Exemplar case study Reducing construction waste saves money Bridge Learning Campus, Bristol Contractor: Skanska Background The Bridge Learning Campus (Bristol) ( BLC ) was used as a test bed for achieving ambitious targets for waste recovery and recycled content in construction. Skanska improved resource efficiency by: focusing on waste prevention, waste reduction and segregation; selecting materials with an above standard recycled content; and re-using waste materials on site where ever possible. Savings 600,000 saved by reducing waste (1.82% of construction value). 550 tonnes of waste prevented. Table 1: Quantified savings Disposal cost reduction (waste reduction and segregation) 348,000 Value of materials saved through waste reduction (minus the estimated cost of achieving reductions) 96,000 Landfill tax saving through cut and fill balance 156,000 Total quantified saving 600,000 This does not include non-quantified savings that may have been achieved from the diversion of strip-out waste from landfill, takeback schemes and reduced haulage. Key benefits: significant cost savings less waste leaving site; decreased over-ordering; a tidier, more efficient site; and wider community benefits. Project details The project was procured as one of the Building Schools for the Future ( BSF ) Pathfinder Projects in Bristol. Bristol City Council set demanding targets for waste recovery and recycled content. The Campus includes a primary school, secondary school, special school, student support centre and dedicated Bridge College. The estimated construction cost is 33 million. Construction started in January 2007 and practical completion for the building was December Reducing waste became part of the way we did construction. Skanska Halving Waste to Landfill

2 Key savings Quantified benefits Skanska now views construction waste as an opportunity to save money and increase efficiency. The Bridge Learning Campus during construction Table 2: Disposal cost saving Wastage and segregation at BLC Disposal cost 1. Standard practice (1,660 t) 394,000 non-segregated 2. Actual wastage (1,100 t) - 261,000 non-segregated 3. Actual wastage (1,100 t) segregated 46,000 Saving (1 minus 3) 348,000 The waste Key Performance Indicators (KPIs) were set up to meet Bristol City Council s requirements, but Skanska soon became aware of the wider benefits and cost savings. The following cost savings were quantified using project waste data and by applying WRAP analysis methods: Actual disposal cost saving of 348,000 through waste reduction and segregation. Skanska compared the disposal cost (per tonne) achieved at BLC through site segregation, against data from other BSF sites: - Segregated waste 42 per tonne - Non segregated waste 238 per tonne Cost of waste disposal reduced to 0.14% of construction cost (construction waste only). Standard practice (non-segregated) would be 1.19% (based on Net Waste Tool analysis of standard practice waste arisings). Estimated 96,000 saved in material purchase costs. A cost benefit analysis of the project, using WRAP s Net Waste Tool, was undertaken to evaluate the net impact of waste reduction from 1,660 tonnes forecast standard practice to 1,100 actual practice. Landfill tax saving of 156,000 through achieving cut and fill balance (a conservative figure as this excludes associated haulage and waste management contractor costs). Additional benefits Quantified improvement in project sustainability performance. A tidier, better run and more efficient site. Demonstrated ability to exceed waste KPI targets. Experience gained will be applied to setting new targets on new projects. Use of innovative paint disposal system which will be rolled out to future projects. Recycling of site canteen waste oil. Waste oil was taken from site by a local firm that re-processed the oil into approximately 100 litres of biodiesel. Positive community engagement through Scout Enterprises re using kitchens and toilets from the redundant school.

3 Lessons Learned Skanska plans to implement the following initiatives to improve future performance: 1. Trade supervisors will be trained on sustainability issues (including waste) alongside CDM briefings. 2. Waste management contractors will be appointed early on projects to help with a segregation strategy. Regular meetings throughout the life of the project will deliver continuous improvement (such as changing the skip segregation strategy). 3. Trade subcontractors will be consulted as early as possible to get their input on reducing wastage rates. 4. Internal waste management auditing and reporting systems will be modernised and waste recording software updated. 5. The waste hierarchy: prevent, reduce, reuse, recycle, dispose, will be followed to achieve the most cost effective waste reductions. 6. Designers will be asked to identify opportunities to prevent (design out) waste. Further waste reductions could be achieved through pre-fabrication of elements such as teaching boards, or pursuing dimensional coordination. Waste Targets on BLC Skanska has set environmental performance indicator (EPI) targets for all its projects including: 80% of all staff must receive environmental training; and sites must segregate waste streams and identify recycled content in building materials by value. Bristol Schools KPIs Skanska agreed KPIs with Bristol City Council in their Partnering Agreement to build four new schools. The following targets were exceeded without pushing up prices: Mean volume of construction waste against value of projects (excluding excavation or demolition waste): <65m 3 per 100k and <43m 3 per 100k (stretch target) of construction spend. BLC achieved 8.3m 3 per 100k. Recycled content (measured by value) of 12%. BLC achieved 21%. Minimise waste and maximise re-use. Two targets, one stretch: >40% recycled and >55% recycled. BLC achieved 71%. Table 3: Waste generation benchmarks WRAP Waste generation benchmarks for a secondary school Baseline Practice Good Practice Tonnes generated per 100k of construction value 6 t/ 100k 3 t/ 100k 7. Local organisations and charities will be involved in waste reduction, such as Skanska s collaboration with Scout Enterprises to strip out and reuse old kitchens and toilets. Bridge Learning Campus achievement Benchmarks taken from WRAP s cost benefit case studies. 3.3 t/ 100k

4 Design Stage - waste prevention Waste was tackled on the project as part of the BREEAM process as BLC had a BREEAM Very Good target, which it achieved. Designers achieved the following as a result: Cut and fill Achieving cut and fill balance provided significant savings. 50,000m 3 of excavation waste was produced from site re-profiling. The excavation arisings were used to level the site and create playing fields. This prevented 62,500 tonnes of excavation waste going to landfill, saving 156,000 in landfill tax. This does not include haulage and waste contractor costs, which would also have been reduced. Design co-ordination The architects coordinated the design of windows, window bracing and plasterboard sizing to ensure all elements fitted together. This meant work on site was quicker, more efficient and fewer material offcuts were generated by the relevant trades. Community engagement Skanska invited Scout Enterprises, a charity affiliated to the local youth Scout Club, to take any materials from the previous school building prior to demolition work commencing. The charity found a use for the kitchens, toilets, PC s and laptops. Salvaged kitchens and toilets were fitted to Scout huts in Wales. This reduced demolition arisings and disposal costs, and provided community benefits. Recycled Content The WRAP Net Waste Tool was used to identify the top opportunities to increase the use of products with good practice levels of recycled content. The project achieved 21% recycled content (by value) of all materials used. This exceeded Skanska s 12% target. Construction Stage - waste recovery Waste Segregation The site manager took an active role in establishing and monitoring the site waste segregation strategy. The design managers ensured the construction team reported on waste, energy and water usage. Innovative paint disposal Painters were provided with a contained system to wash down brushes, rollers and hands. The filtration tank encouraged trades to not illegally wash down in standard sinks. The system helped to ensure legal compliance and reduced the volume (and therefore the cost) of waste water arisings. Take back schemes Arrangements were made with ceiling tile suppliers for ceiling tile offcuts to be segregated on site and collected by the supplier. The offcuts were then remanufactured into new ceiling tiles. Used timber pallets were segregated on site to be collected by local firm Woodwise, who recycled these into biomass boiler grade wood pellets. BLC will be supplied with wood pellets for its biomass boilers from Woodwise an example of closed loop recycling. Cost Benefit Analysis (modelled figures) 1 Following completion of the BLC, WRAP undertook a Cost Benefit Analysis (CBA) using the Net Waste Tool, to estimate the value of materials saved through generating less waste 2. The analysis calculated the project s waste arisings at baseline (typical practice) and then at good practice levels. The difference between the two is the saving in material purchase costs. An example poster from Skanska s on site awareness raising campaign about the cost of waste 1 This part of the case study presents data that were modelled. Note in Table 4 Net Benefit was 0.29% of construction value. This is less than 1.82% on the front page, as these modelled data excluded i) segregation waste savings and ii) savings in landfill tax. 2 Although the Net Waste Tool models them, disposal cost savings from waste reduction and segregation are not included here as these costs are already included in Table 2 previously.

5 Table 4: Waste Savings and Costs (A) Value of materials saved 117,000 (B) Costs to achieve savings 21,000 (A-B) Net benefit 96,000 Net Benefit is equivalent to 0.29% of construction value The following materials savings were achievable (difference between baseline and good practice wastage rates) 3 : Roofing 31,000 Blockwork 23,000 Concrete 22,000 When other smaller savings are added, the total gross saving is 117,000 (value of materials saved). In future, Skanska will assess the net benefit of preventing, reducing and segregating waste at an early stage in their project, to identify the most cost effective actions to reduce waste. For more information, visit the construction pages of our web site at You can access: a range of other exemplar and cost benefit case studies; information on procurement guidance and model wording; the Net Waste Tool and Designing out Waste tools (free online tool for quantifying waste arisings on construction projects); WRAP s Site Waste Management Plan Template; and guidance on Designing out Waste. Estimated costs to achieve reductions The estimated labour and site costs to achieve the savings was 21,000. The most significant costs relate to material storage on site, preparation of the Site Waste Management Plan, and the cost of an operative to oversee segregation. 3 These are modelled baseline and good practice wastage rates. However, as Table 3 shows, good practice was very close to the actual waste performance at BLC. While steps have been taken to ensure its accuracy, WRAP cannot accept responsibility or be held liable to any person for any loss or damage arising out of or in connection with this information being inaccurate, incomplete or misleading. This material is copyrighted. It may be reproduced free of charge subject to the material being accurate and not used in a misleading context. The source of the material must be identified and the copyright status acknowledged. This material must not be used to endorse or used to suggest WRAP s endorsement of a commercial product or service. For more details, please refer to our Terms & Conditions on our website Waste & Resources Action Programme The Old Academy 21 Horse Fair Banbury, Oxon OX16 0AH Tel: Fax: info@wrap.org.uk Helpline freephone