Even in the tough economic climate that has persisted in recent years structural steelwork has continued to increase its market share of the UK construction sector.
Steel is enjoying increasing recognition as the preferred construction framing material for multi storey non-residential buildings, as the latest survey from independent market research consultants Construction Markets confirms.
The 2011 survey, commissioned by the British Constructional Steelwork Association (BCSA) and Tata Steel, is the latest in a series going back to 1980 and is thought to be the biggest of its type in the UK, involving over 450 interviews with construction specifiers.
The survey shows that steel frames continue to dominate the multi story market with a 67.7% market share, despite the difficult construction market conditions. The survey also shows that the market contracted by a further 6.3% in 2011, with overall floor area constructed in all multi storey buildings reducing to 10,850,000m2, which was only 71% of the size of the market in its peak of 2008, when it was 15,266,000m2.
Steel now has a 69.4% share of the multi storey offices market. In the ‘other multi storey buildings’ sector, which includes retail, education, leisure and health, steel has a 67.3% share.
One of the reasons why steel is increasing its market share is the sustainability benefits which the material brings to the table. A new report based on research by quantity surveyor Gardiner & Theobald (G&T), consultant Peter Brett Associates (PBA) and contractor Mace shows higher sustainability being achieved on steel framed buildings than concrete alternatives. The steel frames’ sustainability benefits such as lower embodied are also being delivered at a lower cost than alternatives.
The report, the latest in the Cost Comparison Study series commissioned by the BCSA and Tata Steel, shows the cost and lower embodied carbon benefits of steel being delivered on two typical modern office blocks – a three storey business park office building, Building 1, and an eight storey city centre office, Building 2.
The frames were designed by PBA, with cost information for each option from G&T with Mace considering buildability, logistics and programme. PBA also carried out an embodied carbon assessment for Building 2.
The report shows that the total building cost for the steel options are on average five per cent lower than the concrete options because of lower floor and frame costs, smaller foundations, lightweight roofs, lower storey heights, reduced cladding costs and reduced preliminaries costs.
The steel framed options were up to nine per cent lower than for concrete when the frame and upper floors alone were considered. Construction programmes for steel framed solutions were 13% shorter compared with concrete framed buildings for the three storey office, and 11% shorter for the eight storey city centre office.
The city centre office cellular steel option also had an 18-30 per cent lower embodied carbon total than the post tensioned band beam option.
New design guidance
In order to maintain steel’s market leading sustainability credentials, the BCSA and Tata Steel have completed a £1M project to provide guidance on the design and construction of sustainable, low and zero carbon buildings.
Known as Target Zero, this project took two and half years to complete and is the first ever study to make a detailed comparison of different energy efficiency measures and low or zero carbon technologies to identify the most cost effective means of carbon reduction.
The Government has set a deadline for all new buildings to be zero carbon by 2019. Five Target Zero guidance reports have been published, each one explaining a different building type and providing the results of in-depth research to help construction professionals understand the most effective routes to achieve this Government objective.
The five building types are schools, warehouses, supermarkets, offices and mixed use buildings. Design information from actual buildings was used for each of the guides and this was then theoretically ‘stripped back’ to meet the minimum requirements for the 2006 Part L of the Building Regulations.
These changes to the fabric and services of the actual buildings created the base case buildings which were used as benchmarks for the study. Independent consultants Aecom carried out the study, assisted by the Steel Construction Institute and Sweett Group.
Together they applied energy efficiency measures and other sustainable improvements to the base cases so that their effect could be measured and fully costed over a 25 year period.
The research for each building type considered operational carbon emissions, embodied carbon emissions and BREEAM, which is the world’s leading assessment method for sustainable buildings
The guidance provides insights on the cost effectiveness of different operational energy efficiency measures; it provides the embodied energy of various construction forms using a whole-life assessment; and advises on how the three highest BREEAM ratings can be achieved.
Target Zero guidance covers many complex solutions, but also highlights that some simple measures can be very effective. Many require little outlay in cash terms, but just require some forethought during the design stage.
Prior to the publication of the Target Zero reports, there was very little information available on this subject. Now construction designers have been supplied with a wealth of information from the steel sector which is available for download at http://www.targetzero.info.
Whole life performance
Assessing the environmental performance of buildings materials plays a crucial role not just for users but for the sector as a whole. The BCSA and Tata Steel say they are committed to helping the construction industry obtain a true and accurate picture, consequently a whole life ‘cradle-to-grave’ assessment is the next step.
Known as Lifecycle Assessment (LCA), the method will allow designers and clients to know how much environmental impact is embodied within construction products.
The method takes into account the product’s entire life cycle from production right through to the construction and even the eventual demolition phase.
Steel benefits hugely from a cradle-to-grave analysis as it can be re-used or recycled endlessly without loss of property or performance. Other materials, such as timber, do not compare as favourably. Timber sent to landfill will decay to form methane, which is 20 times more virulent as a greenhouse gas than carbon dioxide. Recent industry figures indicate that up to 80% of timber waste in the UK goes to landfill.
Peter Brett Associates (PBA) has carried out an embodied carbon assessment for a typical building using steel or concrete framing options. It considered the whole building rather than just the structural frame and focussed on the emissions from these elements.
The impact of using steel bearing piles on embodied carbon for both steel and concrete frames was also assessed. It was reported that the use of steel bearing piles results in an increased number and length of piles for both frame options; however, there are offsets in terms of a significant reduction in the size of pile caps and associated reductions to excavation and disposal for both options.
Steel bearing piles can also be extracted at end of life and recycled or re-used elsewhere.
Steel's safety culture shows results
Statistics for BCSA members in 2011 reveal that the number of reportable accidents recorded under Reportable Injuries Diseases and Dangerous Occurrences Regulations (RIDDOR) has been reduced by 25%.
The BCSA says the 25% reduction demonstrates the industry is committed to improving working practices and procedures, some of which are developed with the BCSA health and safety committee to address the current issues and best practice that is based on their shared experiences and intended to help to reduce accidents and injuries.
Records for 2011 also show there were no fatal injuries, while major injuries were reduced from 18 in 2010 to 15.
Over three day injuries (those that involved a person being absent from work for more than three days) was reduced from 100 reported in 2010 to 75 for 2011. Handling, lifting and carrying as well as slips, trips and falls were the two main categories to report a reduced accident rate.