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Key to many of the government’s plans for the future infrastructure of the UK, is the use of prefabrication, particularly prefabricated concrete structures.
This is predominantly the case in:
- Projects for transport infrastructure, including roads and railways, using prefabricated tunnel and bridge sections (for example, HS2, where over 100,000 prefabricated tunnelling segments are being used, as well as prefabricated buildings and 3D printing of heavy engineering sections).
- NHS Projects for new or extended hospitals.
- Custodial and secure projects for law enforcement.
- Power generation projects, including new build nuclear projects (for example, at Hinkley Point C, where the second reactor base was constructed in the same timeframe as the first with 25% quicker reinforcement rates, notwithstanding it being designed with 46% more steel).
- Defence projects.
- Water infrastructure.
- Public housing.
Using off-site fabrication, especially for prefabricated concrete structures, can have distinct advantages, such as:
- Better sustainability.
- Quicker installation.
- More cost-effectiveness.
- Shorter lead-in times.
- More bespoke build options.
- Better efficiency during production (as well as more consistency and quality of output given the controlled factory surroundings as opposed to variable on-site conditions).
- Less waste produced.
- Less labour-intensive.
- A reduced need for operatives on-site.
- Less work at height or in bad weather.
- Improved health and safety on site.
Whole life cost can also be improved as better and earlier quality control can decrease permeability as well as increasing life span by accounting for future issues. Recent research supporting some of the advantages listed above indicates that prefabricated homes built offsite can be constructed 30% more quickly, and at a 25% reduced cost.
A further, recent survey undertaken by the Electrical Contractors Association demonstrated that 59% of respondents found a reduced operational cost when using off-site techniques. In addition, 57% saw an increase in the quality of work and 61% attributed these techniques to a rise in productivity.
Currently however, only 7% of UK construction is undertaken utilising offsite modular construction techniques, and of that figure, fewer are utilising prefabricated concrete. This puts the UK behind Germany (9%), Japan (12%) and Sweden (20%).
High energy prices may, however, put such innovation at risk in coming years.
Despite the introduction of the recent Energy Bill Relief Scheme, which will, to some extent for the next few months, reduce the burden on business users of electricity and gas from October this year until March 2023, prefabricated techniques, especially those involving prefabricated concrete structures, are still relatively energy intensive.
Although the industry has reduced energy consumption dramatically by some 53% since 1990, precast factory energy consumption was still around 47.9 kWh/t in 2019 and concrete production is still thought to account for between 4% and 8% of world CO2 emissions.
In addition, the short term nature of the Energy Bill Relief Scheme does not account for infrastructure projects which are usually long term, to maintain the strategy for the UK’s national infrastructure using off-site fabrication, especially of concrete modules. Hence, the industry is likely to be less incentivised, by high energy prices, to use the more advantageous construction techniques of precast concrete fabrication.
Comment
While the government’s Energy Bill Relief Scheme is welcomed, further governmental support may be needed to encourage more innovative construction techniques in the longer term, despite rising energy costs.
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United Kingdom