You’re right in that we don’t have any/many templates for prefabrication. It’s not very common therefore there has not been much demand for such a template. Generally if we were to model this in-house, to demonstrate the benefit of using prefabricated building materials, we would use the standard templates in the Reference/Business-As-Usual design. Then in the Proposed design, make the following updates to the relevant templates to demonstrate the benefit of using prefabricated methods:
- Lower construction waste factors: assumed that the factory would be able to cut things to a more standardised size with less waste than on-site construction (adjusted within template). You can consider using the bulk-swap tool to do this.
- Lower transport distances for trades in the factor (changes to be made within the Design after template has been added): The reason for this assumption is that you assume that if you’ve got a job at a factory you have more ability to live close to it, if you have a job that moves to a different site every 2nd day you’re likely going to find it very hard to minimise your transport distances to work. Again, the Bulk Swap Tool will be useful here.
- Once-off truck equipment item to account for the transport of the prefabricated unit to the site (may be adjusted within template after adding to the design).
If you submit your design for certification/review, please ensure that your supporting documentation is very clear and succinct on the assumptions made and references you’ve used plus the changes and edits you have made to the templates to reflect the prefabricated nature of the construction to facilitate the review process.
Regarding Life Cycle Modules – please note that at the moment in eToolLCD, ‘Offsite Factory Prefabrication’ under ‘Equipment’ impacts is incorrectly reported under Module A5 when it should be A1-A3. This should not significantly impact the study however if required, this can be manually reported under the correct module outside of eToolLCD.
A note for categorisation – Although BRE favours the RICs NRM, we actually believe that it would benefit the study more to provide more granularity and transparency by categorising the different parts of the prefab modules accordingly (i.e. floors, roof, walls, floors as opposed to all items under the ‘Prefabricated Buildings’ category). Perhaps this issue can be clarified with BRE if your study is for BREEAM. However if it’s not, we would prefer the former method of categorisation.