Waste Reduction Potential of Light Steel

Transcription

1 WAS : Offsite Construction Case Study Waste Reduction Potential of Light Steel Frame Construction Light steel frame construction reduces waste through design, appropriate procurement routes and controlled production lines to a level of 1%, all of which is reused or recycled. Project code: WAS Research date: [Add date range of research] ISBN: [Add reference] Date: [Add date of report]

2 Front cover photograph: Framing Solution Pre-fabricated wall panel being lifted from reusable delivery rack WRAP and Mtech Consult Ltd believe the content of this report to be correct as at the date of writing. However, factors such as prices, levels of recycled content and regulatory requirements are subject to change and users of the report should check with their suppliers to confirm the current situation. In addition, care should be taken in using any of the cost information provided as it is based upon numerous project-specific assumptions (such as scale, location, tender context, etc.). The report does not claim to be exhaustive, nor does it claim to cover all relevant products and specifications available on the market. While steps have been taken to ensure accuracy, WRAP and Mtech Consult Ltd 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. It is the responsibility of the potential user of a material or product to consult with the supplier or manufacturer and ascertain whether a particular product will satisfy their specific requirements. The listing or featuring of a particular product or company does not constitute an endorsement by WRAP and WRAP cannot guarantee the performance of individual products or materials. For more detail, please refer to WRAP's Terms & Conditions on its web site: Published by Waste & Resources The Old Academy Tel: Helpline freephone Action Programme 21 Horse Fair Fax: Banbury, Oxon info@wrap.org.uk OX16 0AH

3 Executive summary The design and manufacturing process of LSF wall panels and floor cassettes borrows techniques and approaches from the automotive industry. The principles of a lean process are just-in-time deliveries, optimisation and rationalisation of the use of materials. All of which equate to a better and more accurate design, a well managed procurement chain, and a significant reduction of wasted resources and materials. This case study uses Framing Solutions as an exemplar to highlight the waste minimisation potential of offsite manufacture. They are a manufacturer of LSF elements for walls and floors. Analyses of their manufacturing and installation process shows that material waste arisings are less than 1% of the total materials used, and that this waste is fully reused or recycled. This achievement is the result of continuous improvement schemes at all levels and stages of the process, from inception of the projects to the erection and handover of the structures to the clients. At the design stage, an engineer will ensure that the structural and thermal performance of the completed building will be met through optimised usage of steel structural members in the panels, so to avoid high degrees of structural redundancy of such stud framing concepts. The use of tri-dimensional CAD-CAM software allows companies like Framing Solutions to achieve this optimised engineering and helps the company to save up to 5% of steel when compared to more traditional LSF design approaches. The factory environment in which the panels are assembled, and the use of automated machinery and plant for some of the operations also opens opportunities for better use of resources and materials. The roll forming machinery and its optimisation software at Framing Solutions were recently amended so to reduce the amount of steel loss through the operation of machinery to 1%. This proportion of lost steel is mainly due to unavoidable cut outs for holes in the stud sections but is fully recycled. Wastage from the chipboard used in the floor panels is also minimised through the optimisation of board sizes and cutting patterns at the design stage. The lean manufacturing process therefore produces a very limited amount of waste, as illustrated by Table 1, which is either reused or recycled. This is also reflected on site where the use of LSF structure can save between 40% and 70% of the waste normally generated on construction sites. Table 1: Summary of saved materials and waste generated (Framing Solutions as an example) Activities Waste generated Waste disposal (%) Saved Material Type % Reuse Recycle Landfill (%) Design accurate engineering None -/- -/- -/- -/- Steel (-5%) Chipboard cutting patterns None -/- -/- -/- -/- Timber (4%) Process Review Optimisation of rolling machinery None -/- -/- -/- -/- Steel (-6%) Procurement Pre-cut steel joists for floor cassettes None -/- -/- -/- -/- Steel (15%) New rivet sizes None -/- -/- -/- -/- Materials (-12%) Manufacturing Steel structural member rolling process Steel 1% Fraction 100% 0% -/- Floor decking Timber based 5% 100% 0% 0% -/- Shipping Use of recycled timber pallets returned Timber to factory based 0% 100% 0% 0% -/- Packaging use of re-usable stillages None -/- -/- -/- -/- Plastic / timber pallets/ etc. Optimisation and planning of transport Lorry Movements None -/- -/- -/- -/- (grouped consignments) (-8%) Erection site activities Steel 0% 0% 0% 0% -/- Insulation 12% 95% 5% 5% -/- Waste Reduction Potential of Light Steel Frame Construction 1

4 Contents 1.0 Introduction Light Steel Frame Construction The system Market LSF and waste Framing Solutions Framing Solutions attitude towards waste Dealing with waste of resources: the Kaizen method Estimation and Design Stage Manufacturing of LSF panels Delivery on site Conclusion Waste Reduction Potential of Light Steel Frame Construction 2

5 1.0 Introduction In the course of the last ten to fifteen years, offsite methods of construction have grown from a very modest market share to, in some cases, becoming standard forms of construction. Some offsite methods or systems are very simple (e.g. roof trusses, pre-cast concrete floors) whilst others are more sophisticated (e.g. advanced panel systems, floor cassettes, modular wiring) in that they involve more of the traditional building process within the factory produced elements. Due to the underlying precise design procedures and factory based manufacturing process, offsite construction offers many advantages when compared to more traditional building methods such as reduced waste generation, better quality control, shorter construction times and improved health and safety. Light steel frame system (LSF) is a growing offsite construction method that has acquired a proven track record for single and multiple occupancy dwellings as well as commercial and industrial applications. Some of the leading manufacturers have developed and adopted lean manufacturing and installation process, not dissimilar in philosophy from the process used in the automotive industry. This approach led to controlled manufacturing units where rigorous procedures were implemented resulting in a significant reduction of resource and materials waste. This case study highlights the many advantages that LSF offsite manufacturing offers in terms of waste minimisation, resource utilisation, and efficiency on construction sites. 2.0 Light Steel Frame Construction The light steel frame construction (LSF) technique has evolved and partly substituted timber frame superstructure for dwellings in the US when, in the 1980 s, the price of timber soared to unprecedented levels. This increase in costs of timber threatened, in those years, the economical balance between the costs of house construction and selling prices, particularly in North America and Australia. This method of construction was developed by the plasterboard industry in cooperation with steel manufacturers, based on the use of cold form slender sections. The techniques were also developed to give developers systems that were similar to timber frame techniques in terms of design and construction methods. Light steel frame methods are now established all over the world and represent a significant proportion of the new build dwellings in Australia (nearly 15%), in the UK (8% to 12%) and in North America (2% to 3%). The use of LSF for internal partitions and infill panels (interior and exterior walls) for commercial, institutional and industrial construction is now commonly used throughout Europe and North America. In the UK, LSF systems are used mainly for the following applications: Single occupancy dwellings (up to 3 storeys) as the superstructure of walls and floors; Medium rise buildings / multi-occupancy buildings (up to 12 storeys as load-bearing structure); Infill exterior wall panels for medium and high rise buildings commercial, institutional and residential; and Interior load bearing and non-load bearing structures residential, commercial, industrial and institutional. The LSF market is characterised by the following forms of assembly: Stick build: Generally constructed on site from pre-cut steel components. For new build structures, the erection drawings clearly show the position of each of the steel members. This can be used for wall and floor structures. Waste Reduction Potential of Light Steel Frame Construction 3

6 Panelised walls: Panels manufactured at the factory which are brought to site where they are assembled together to form structural load bearing walls (e.g. houses), non-load bearing partitions or infill panels. Panelised walls can be manufactured to include any of the following: insulation, doors, windows, services, exterior finishes, and interior lining. Floor/roof cassettes: larger elements can also be manufactured for floors or roofs. Similarly to the wall panels, these elements include joists, beams, and floor boards. In some more advanced cases, insulation, lining, services, etc. can be added at the factory prior to shipping and delivery on site. 2.1 The system LSF wall systems are composed of vertically aligned galvanised steel members (or studs) that are maintained and tied together to top and bottom rails. The spacing between the studs varies according to the loading applied to the wall structures, but never exceeds 600mm. The racking resistance of the panels is ensured by means of cross bracing using flat galvanised strips. These panels are assembled in factories using a variety of fixing systems that are specific to the different manufacturers (e.g. self drilling screws, rivets, welding, etc). Floor structures are made of galvanised cold formed sections equally spaced that are tied to peripheral ring joists. A chipboard sub-floor platform is subsequently fixed to the top flange of the joist and weather protected. Depending on the manufacturer and the on site conditions, the floor structures may be assembled at the factory and delivered on site as large factory assembled elements, referred to as floor cassettes. This method of construction and delivery of floor offers the same advantages of pre-fabricated wall panels. When there are no requirements for living space in the roof, the roof structures are made of standard timber trusses. The choice of standard roof trusses is justified by the low costs of the pre-fabricated timber trusses structure compared to equivalent elements made of steel. However, the use of steel rafters and LSF components for roofs is economically sound for roof designs that include a living space. The wall panels are delivered on site either on specially designed reusable stillage or in flat bundles. Once on site, the panels are easily identifiable and can be assembled together rapidly by appropriately trained personal and with a limited number of hand and power tools. The rigid insulation boards are generally fixed on site on the exterior face of the exterior walls. Brick ties, when required, are installed at the same time, ready for the brick layers to use. 2.2 Market Although cold formed steel had been used quite extensively in industrial, commercial and institutional construction for a number of years, light steel frame panels have only been in regular use in the residential sector for the last years. Waste Reduction Potential of Light Steel Frame Construction 4

7 The percentage of residential light steel frame construction in the UK has however been increasing in the last 5-10 years, particularly as multi-storey flats and apartments on relatively tight sites has become more common throughout inner city areas of the UK. LSF is now starting to be perceived by specifiers and developers as a reliable construction method for multi-story, multi occupancy construction, possibly up to storeys. Today s LSF market share is in the region of 6% of the UK residential markets for dwellings and apartment blocks under 5 storeys (SOURCE: STEEL CONSTRUCTION INSTITUTE). Major market players in LSF in 2005 included: Bourne Steel Framing Solutions Fusion Building Systems Metek Building Systems (now re-launched as EOS Ltd) The turnover for the LSF industry was estimated to be around 80m for This includes all forms of light steel frame construction as well as the value of site erection work. Unlike timber frame, light steel frame remains a more immature market so that different manufacturers continue to offer slightly different systems in order to gain or secure market share within this growing market sector. 2.3 LSF and waste Due to the high accuracy level in design and manufacturing of LSF panels, the delivered structures do not require modifications or adjustments during the erection stage. Once on site only a limited number of materials are needed to complete the structure and, due to the precision level of the design, this additional material is delivered to site in controlled quantities to avoid unnecessary wastage. Such additional materials include: Screws or other fixings; Shims for levelling ; Base rails / sole plate; DPC and DPM membranes where required; and Additional pre-cut strengtheners and floor boards. Due to this controlled process the waste directly associated to the construction is limited and is mostly generated at the factory and during the preparation for the insulation for the exterior walls. This waste, however, represent a very small portion of the waste that would be generated for the equivalent work on more traditional construction sites. It has been shown that the use of LSF has been seen to reduce waste on construction sites to between 40 and 70% compared to traditional build depending on the extent of offsite fabrication. This case study utilises data from Framing Solutions to demonstrate the potential for waste reduction through the use of LSF produced in a modern manufacturing facility and its impact on the overall construction waste generation. 3.0 Framing Solutions Framing Solutions plc is jointly owned by Redrow and Corus Steel. Since 1982, Framing Solutions plc has supplied steel frame panels to the construction industry. Its product has constantly evolved due to continuous research and improvements, both to the product and to the production process. Surebuild is the name adopted by Framing Solutions for its LSF based system. The Surebuild system has been developed specifically with the requirements of UK construction and end users in mind. Working in close cooperation, often partnered, with clients, contractors, architects and industry specialists (such as the Steel Construction Institute, Oxford Brooks University and Corus Building Systems), Framing Solutions has developed improved systems and processes over an extensive period, presenting the market with tried and tested construction solutions, proven in over 20 years of construction. Waste Reduction Potential of Light Steel Frame Construction 5

8 3.1 Framing Solutions attitude towards waste Light steel frame techniques are simple and rely on elementary components being fixed together to meet performance criteria determined by end-clients, architects, engineers, and the Building Regulations. This has permitted the industry to rationalise and optimise the design and manufacturing processes and activities. Therefore, management of most of the larger offsite LSF manufacturers have set up processes and procedures that are very similar to those used in the automotive industry where waste management is very sensitive and critical to the industry s competitiveness. Consequently, the processes like those put in place at Framing Solutions focus on: Ensuring that each project is suited for LSF. Early in the emergence of LSF in the construction market, the LSF suppliers accepted to work on projects that were not suited to LSF techniques and for which clients and architects would not accept modifications. As a consequence, some projects resulted in resource and time losses as well as greater than anticipated generation of waste. By carefully assessing each project at the estimation stage, Framing Solutions is able to open up a dialogue with its clients and to propose modifications to the scheme that would better suit LSF techniques whilst respecting the original design. In cases where Framing Solutions considers that LSF does not suit the design, the invitation for bidding will be decline, saving time and resources as well as eliminating waste that results from changes in design and manufacturing. Ensuring that the basic materials used are sustainable. The steel components used are made of a high proportion of recycled content. Optimising the design of each LSF panel for each project. Traditionally, Light Steel Frame design was based on standard design tables and construction principles, which resulted in a high level of structural redundancy. Through the use of better refined modelling and design software, and the increased understanding of the material performance, it is now possible to reduce the amount of steel necessary by carefully designing buildings taking into account local loading patterns, as well as tri-dimensional structural analysis. Optimising the use of machinery, equipment and plant. Most of the automated machinery is computer operated. With time, the software first developed to run that machinery can be modified to better suit the needs of the manufacturer, and to reduce the amount of waste generated by such machinery. Further more, it may also be possible to increase the productivity of the machinery whilst decreasing the amount of waste generated and energy consumed. Reviewing procedures on a regular basis, involving personnel throughout the company. By involving key personnel in reviewing the process, procedures and details on a regular basis, not only do the personnel buy into new methods and awareness scheme, but help in improving the whole process and construction details. This rationalisation and optimisation process ultimately saves resources, materials and waste. Ensuring continuity of the factory approach to the construction site. The LSF industry is adamant that all the effort made at the factory must be transferred onto the construction site. Therefore, erection methods, tools necessary for the erection and additional materials are all developed with the same rational and lean approach adopted in the factory. Waste Reduction Potential of Light Steel Frame Construction 6

9 Reuse or recycling the unavoidable waste. By involving all personnel, partners and suppliers into waste segregation, minimisation, recycling and reuse, the manufacturers have the ability to instigate behavioural changes. Environmentally aware organisation like Framing Solution consider waste minimisation, encompassing steps to reduce wastage of energy, resources, time and materials to be important. Commitment to better usage of materials reaches beyond the scope of the production facilities into the erection phase and the ultimate end use of the LSF products. Analyses of their manufacturing and installation process shows that material waste arisings are less than 1% of the total materials used, and that this waste is fully reused or recycled. 3.2 Dealing with waste of resources: the Kaizen method Framing Solutions Ltd recognises the importance of establishing a sound business backed up by lean management methods. Therefore, the whole process from enquiries through to deliveries on site is constantly reviewed in order to identify the areas where material, resource and time efficiencies could be improved. This method is based on the Japanese Kaizen approach that has made automotive manufacturers so successful, to substantially decrease the wastage at all stages of the manufacturing process and to improve productivity. More importantly, this management method involves all member of staff, from the Managing Director down to the operatives on the factory floor as well as the erection teams. By involving the personnel at all levels, the company ensures that an optimal solution is developed taking into account all the different views from the different users. Therefore, when implemented, the solutions are more likely to be widely accepted and adhered to. The Kaizen method has been used by Framing Solutions to tackle wastage levels as well as optimisation of materials used, including, for example: reduction of waste through the optimised operation of the steel roll forming machinery; reduction of waste on site by limiting access to bulk issue materials such as screws, brick ties, etc; reducing wasted time in the factory through efficient material handling; reuse of steel offcuts; reducing off-cuts of chipboard used for floor cassettes; reducing the overall quantity of materials used, for example reducing the sizes and optimising the types of fastening; optimisation of the use of reuseable stillage for deliveries on site (in cooperation with freight companies); and optimisation of transport and delivery to site maximise transport volumes and logistics planning. These important changes in the manufacturing process led Framing Solutions to valuable reduction in waste as well as in manufacturing costs and offsetting the capital costs incurred by some of the methods instigated and implemented. These reductions are commented later in this report. 3.3 Estimation and Design Stage Like many in the industry, Framing Solutions recognises that LSF construction is suitable for certain types of construction, design, or end-users. By qualifying the enquiries, and ensuring that the architects are willing to slightly modify their design where necessary to suit the techniques associated to LSF, Framing Solutions will quote on projects for which the Surebuild system is beneficial to the clients, thus saving invaluable internal resource time and effort. Once the client approves a scheme and proceeds with the order, the design team will prepare the manufacturing and erection drawings for approval by the clients and for internal review. The design team optimises the structural components of the building using state of the art computer CAD-CAM systems in order to limit the unnecessary use of materials in the manufacturing of the wall panels, floor cassettes and additional materials to be sent on site. To achieve this, the designer will consider the following aspects: Waste Reduction Potential of Light Steel Frame Construction 7

10 Local loadings for wind and snow. This will ensure that the right amount of steel studs are used, and to locate the studs at the appropriate location. Locations of framed openings. The design engineer will contact the architect and the clients in order to modify the position of doors and windows in order to optimise the use of materials. Quantity of materials. The design process permits the engineers to precisely quantify the number of screws, brackets, ties, etc. required for each building. The designer will issue an exact bill of materials for all of the required materials to be shipped to site. Number of different parts. The design engineer will also ensure that, for each of the panels, the number of different parts is limited in order to avoid errors during the manufacturing process. Use of generic details. The designer will also create the building using a limited number of standard details. These few standard details are well known by the factory and erection crews, thus, reducing the risk of errors and waste. Cutting patterns. The designer will also produce cutting patterns for chipboard for floor cassettes and for rigid insulation on site. These are especially important to reduce the amount of wasted materials and to ensure a better utilisation of the chipboard and insulation boards. Design review. All information for each of the buildings to be manufactured is reviewed by the design and manufacturing teams. Comparisons are made with other similar constructions to identify any omissions, design errors, etc that might have occurred. This procedure has proven to be an important step in reducing the costs of errors. The estimation and design stage represent very important steps in the optimisation and reduction of the use of resources (personnel, materials, etc) and of waste throughout manufacturing and erection. Framing Solutions monitoring revealed that these procedures save around 5% on steel consumption compared to more generic LSF design approaches. Furthermore, because the design and production of the LSF elements are interlinked, and feedback from production and erection teams is continuous, it is then possible to impact positively on waste by careful and sensible design improvements. This high volume factory led mentality has allowed Framing Solutions to reduce the production costs of the Surebuild system and to maintain its selling prices over the past few years despite the significant increase in material costs, particularly steel and labour. 3.4 Manufacturing of LSF panels Manufacturing of the LSF panels generally starts four weeks after the completion of the design. This buffer time gives the manufacturing team enough time to review the design and to ensure that the materials required will be available. In order to reduce the cutting operations at the factory and to allow Framing Solution to reduce the amount of waste generated by cutting structural members from standard construction lengths of steel profiles Framing Solutions decided to invest in a rolling machine able to form the steel components for wall panels (studs and channels). The investment made in rolling plant has proven to be effective in saving materials. The use of large coil lengths coupled with the computerised optimisation of the rolling programme significantly reduced the amount of wasted steel form 7% to less than 1%. The wasted galvanised steel is generated through, machine defaults leading to length of steel strips to be discarded, perforations in the studs and rails for services and other areas where required. Although all the steel is sent back to Corus for recycling, it has been decided that some of the perforation chips created by the machine are of the right dimensions to perform quality control tests for rivets. Therefore, some of the chips will be reused for testing or as shims, thus eliminating the need of cutting steel from the coils for testing purposes. The steel joists used for the construction of floor cassettes are provided by local specialist suppliers of steel joists. The partnership allows Framing Solutions to order the joists for just in time deliveries. To avoid further waste, all the joists are delivered to the factory in kits, cut to length and ready to be assembled. Waste Reduction Potential of Light Steel Frame Construction 8

11 The floor deck boards are cut on wall saw benches following optimised cutting patterns. This has proved to be an efficient way of decreasing the amount of timber based waste from around 15% to around 9% of the total passing through the factory. The remaining pieces that can not be used are burnt in a high efficiency furnace to provide heating to the whole factory. Framing Solutions has also looked into the type of rivets that have been used and, through a Kaizen project committee, came out with the proposal to use shorter rivets that have the same mechanical properties as those used until recently. Considering that Framing Solutions uses over 5m rivets a year, the small gain of material per rivet will materialise in a few tons of material saved (1-5tons per year) and a reduced packaging (10% more rivets per box). The same team is now currently working with the rivet suppliers to devise a new reuseable packaging in order to eliminate the waste due to current single use system plastic boxes. This is part of an ongoing activity to reduce waste and increase production efficiency. 3.5 Delivery on site Parallel to the manufacturing process, the logistic / delivery team provides the additional materials that are needed for the erection of the LSF structures on site. This includes screws and anchors etc.. The quantity required for each of these additional parts and materials are precisely modelled by the design team. Recently, Framing Solutions has implemented a policy to encourage the erectors on site to carefully manage these materials by requiring payments for any extra materials ordered in addition to those listed in the bill of materials. This incentive for careful handling of materials created an immediate and significant reduction in the total number of screws, brackets and ties sent to site compared to what used to be shipped prior to this policy being implemented. It appears that the erection crews are now much more careful on site with regards to the handling of these materials and the saving is estimated to around 15tons of materials a year. Once ready, the panels are placed in specially designed stillage. The order of panels in the stillage corresponds to the sequence of erection so that the erection crews can pick the wall panels in the right sequence, directly from the stillage. These stillages are returned to the factory once the panels have been installed. This method of delivery of the panels decreases the requirement for special packaging methods, protects the panels from mud and dirt on site and assists the work of the erectors. Also, the use of stillages reduces the amount of storage space required on site, and allows the erection teams to better manage the deliveries to site. Moreover, by managing the delivery on a just-in-time basis, the risk of damage is significantly reduced thus further minimising wastage on site. The erection teams are either directly employed by Framing Solutions or are subcontractors that are specifically trained by Framing Solutions. The erection teams work closely with the factory and up date their erection programme in co-ordination with the shipping department to ensure just in time deliveries of panels on site. To achieve this, partnership agreements were signed between Framing Solutions and local transport companies. These agreements aim to provide the right transport suited for the consignments to be delivered. So far, these framework agreements have saved up to 8% of the traffic (number of lorries) compared to more traditional shipping methods. Waste Reduction Potential of Light Steel Frame Construction 9

12 4.0 Conclusion Offsite construction methods, such as Light Steel Frame, offer the construction industry means to improve on the quality controls of the materials and components used on sites, shorten the construction programme and help eliminating waste. The use of LSF methods in developments can decrease the total amount of waste generated on site by between 40% and 70%, depending on the degree of offsite fabrication of the elements. Offering a neat and precise methodology of erection, the use of LSF structures reduces the amount of unnecessary materials on site, hence reducing the quantity of waste generated and potential losses of materials due to damage and overordering of materials. This case study draws upon the processes adopted by Framing Solutions and demonstrates the efficiency of the design, manufacturing, delivery and erection associated with LSF, and of the continuous improvement system put in place. Overall, the manufacturing process produces less than 1% of waste which is reused or recycled. In some instances, careful design procedures also allow Framing Solutions to reduce the amount of steel required in a structure by 5% compare to more generic LSF design approach. The production of Light Steel Frame elements takes place in a protected environment where quality controls are rigorously applied at every stage of the manufacturing process. The nature of the factory environment also permits manufacturers like Framing Solutions to optimise the design of the elements, and to maintain a total control on the use of every component that is assembled to form either wall panels or floor cassettes. The management team uses techniques and tools similar to those generally promoted in the automotive industry. The Kaizen method of continuous improvement has helped Framing Solutions to improve a variety of procedures and working process through the factory, from the estimation stage through erection on site. By involving the staff at all levels, it has raised the employees awareness towards better processes and savings in terms of resources, materials and waste. This is an on-going process bound to improve further the manufacturing process and minimisation of waste. At the design stage, careful attention to details and bespoke engineering design allow Framing Solutions to reduce the total amount of steel required to manufacture the building elements without compromising the structural stability or performance of the building once erected. Careful procurement planning associated with lean manufacturing process helps the manufacturers to optimise the utilisation of the resources and materials. By considering the production requirements over 2 to 3 days, it is then possible to rationalise the use of materials and to minimise the generation of waste by precisely evaluating the materials required (screws, boards, steel rolls, etc.) and to devise cutting schedules and patterns that will minimise losses of material. Regular monitoring of the machinery has also led to the identification of some areas where the combined used of software and operative knowledge further minimised wastage. By fine tuning the machinery and modifying aspects of the software and the position of some of the triggers, Framing Solutions has been able to optimise the use of steel coils. The unavoidable wastage currently represents less than 1% of steel consumed for the production of structural members. From this waste, a small percentage is used for rivet testing. All steel waste is collected in specific containers and sent back to the steel suppliers for recycling. Chipboard decking for floor platform is the only timber product used in the Framing Solutions factory. Waste generated by the cassette floor activities represent 5% of the total volume of timber-based product bought. Shortly all timber waste will be burnt in a high efficiency burner that will become the heating source for the whole factory and offices. Waste Reduction Potential of Light Steel Frame Construction 10

13 Further refinement of the assembly details permitted Framing Solution to reduce the total tonnage of rivets used by 1-5% due to the change in the length of rivets. Indeed, technical and structural studies recently carried out showed that smaller stem rivets are as efficient as the long stem rivets previously used. Finally the delivery on site of additional materials such as screws, shims, etc. are now monitored very closely. The design procedures allow the manufacturers to accurately estimate each component required at the factory for manufacturing and all elements and components required on site for the erection of the structures. By implementing a policy whereby the erectors or contractors are charged for materials required above the estimated numbers, Framing Solutions has been able to significantly decrease the amount of material wasted on site. As illustrated in Table 1, the waste generated by the manufacturing and erection processes is minimal. Furthermore, internal review process and controlled design procedures and checks help to decrease the amount of resource and materials required to produce the panels and the cassettes. Overall, LSF superstructure, which would typically replace internal brick work, generates very little waste which is, in turn, either reused or recycled. Thus, very little waste generated by the activities of the manufacturers at their facilities or on site is lost to landfill.. Table 1: Summary of saved materials and waste generated (Framing Solutions as an example) Activities Waste generated Waste disposal (%) Saved Material Type % Reuse Recycle Landfill (%) Design accurate engineering None -/- -/- -/- -/- Steel (-5%) Chipboard cutting patterns None -/- -/- -/- -/- Timber (4%) Process Review Optimisation of rolling machinery None -/- -/- -/- -/- Steel (-6%) Procurement Pre-cut steel joists for floor cassettes None -/- -/- -/- -/- Steel (15%) New rivet sizes None -/- -/- -/- -/- Materials (- 12%) Manufacturing Steel structural member rolling process Steel 1% Fraction 100% 0% -/- Floor decking Timber based 5% 100% 0% 0% -/- Shipping Use of recycled timber pallets Timber returned to factory based 0% 100% 0% 0% -/- Packaging use of re-usable Plastic / timber None -/- -/- -/- -/- stillages pallets/ etc. Optimisation and planning of transport (grouped consignments) Erection site activities None -/- -/- -/- -/- Lorry Movements (-8%) Steel 0% 0% 0% 0% -/- Insulation 12% 95% 5% 5% -/- Waste Reduction Potential of Light Steel Frame Construction 11

14 Written by: With the Participation of: Mtech Consult Limited Maple House The Professional Quarter Shrewsbury Business Park Shrewsbury SY2 6LG Framing Solutions plc William Nadin Way Swadlincote Derbyshire DE11 0BB Published by Waste & Resources The Old Academy Tel: Helpline freephone Action Programme 21 Horse Fair Fax: Banbury, Oxon OX16 0AH