Being a 5D Quantity Surveyor I have been actively following the discussions around Lean Construction for many years now. To me it just seems to sensible to reduce the amount of waste that takes place during the build of a construction project.
Even so, it can be difficult to identify precisely the amount of waste on a project, so it also makes good sense to physically measure waste to understand what is being wasted and how to mitigate it in the future. I recently came across the document “Recommended Practices for the Application of LEAN Construction Methods to Building New Australian LNG Capacity” by Engineers Australia (Western Australia Division) which is one of the clearest documents that I have read in regard to categorising construction waste.
They describe waste as; “… anything which does not add value to the customer“, further breaking down the term into 7 subsections, as follows;
ò Waiting û for materials or specifications
ò Over Production û producing more than is required by the customer
ò Rework û rectification of incorrect or defective work
ò Motion û movement of people around site
ò Processing (over) û doing too much to a job or producing too high a specification when it is not necessary
ò Inventory û too much or too little inventory
ò Transportation û moving equipment, tools or materials around the site and double handling
BIM plays a pivotal role in holding all project data securely in order to deliver cost certainty across the designs, variations and final build. Through this BIM dramatically improves field performance by ensuring compatibilities between trades and areas, minimising clashes, and allowing fabrication issues to surface before construction commences, therefore eliminating multiple areas of the aforementioned wastes and improving construction efficiency.
Owners will ultimately benefit from the efficiencies that come out of BIM but the value of these efficiencies won’t be realised until the market adjusts and we see reductions in allowances by subcontractors for various types of wastes (delay, disruption and rework) currently due to poor documentation and site management. While it will be some years, perhaps five to ten, before market prices show downward pressure there are still a number of savings strategies that can be put into action.
Historically, the way construction projects are priced is to allow high contingencies at the outset and to expect redesign, delays, disruption, rework and variation claims – all adding to project waste. BIM is about being able to reduce the need for contingencies as the gap between project development, modeling and the build narrows.
For those who implement standard methodologies to ensure project teams are involved in the BIM at the right stages of design and development, it will bring about leaner building design and construction that will ensure subcontractor costs are more predictable, negotiations are transparent and various wastes are reduced. Ultimately markets will adjust and we will realise reductions in contingencies, wastes and savings at the outset of projects and collectively achieve greater savings and cost certainty for the industry as whole.
There is no denying that the construction industry is rapidly advancing in the area of BIM. However for BIM to be truly effective in the field it must move away from being just a design tool and act on also reducing waste. Everyone within the industry faces the challenge of bringing technological best practice together to benchmark standards in project delivery for leaner, better buildings.