The 7, 8, or 27 Areas of Waste in Lean Construction?!
Seven Becomes Eight
“DOWNTIME” Areas of Waste by LCI
The Lean Construction Institute (LCI) developed the original seven basic types of waste. Since then, SMEs have been refining the concept, occasionally adding additional dimensions (a la BIM!). One of the easiest ways to remember may be the acronym “DOWNTIME” found in a presentation by LCI and Mortenson Construction published online.
D=Defects: Errors that result in rework and increased costs
O=Overproduction: Producing something either before it is needed or in too great a quantity
W=Waiting: For parts, machines, people
N=Non-utilized Resources: Failing to use the people or resources appropriately
T=Transportation: Unnecessary movement of a product between processes
I=Inventory: Storing product as a result of overproduction
M=Motion: Any movement of man and/or equipment that does not add value to the process
E=Excess processing: Work that is not specifically asked for by the customer
And Then There Were 27
Admittedly, these areas are general placeholders for the actual detailed accounting for waste. A survey of 60 companies conducted on the construction practices in the Abu Dhabi construction industry, identified 27 areas of waste!
What’s interesting about this analysis is that they were able to (first) relate all 27 down to the seven original categories, and (secondly) identify the causes.
The first four causes, which represent 38% of all causes, were located ONSITE: material shortage, unskilled labor, poor supervision, and bad storage (below).
With all of this (and much more, read the entire paper here), how did it end for the AD industry as a whole? Here’s the conclusion:
Analysis of of AD construction industry revealed 27 types of construction wastes. These wastes were categorized into the commonly used seven types of wastes in lean production. Defects (errors and corrections) are found to be the most common type of construction waste in the surveyed companies. This called for the integration of a structured and data-driven quality improvement method (namely, Six Sigma) into the lean construction framework. The second common types of wastes are over-processing and delays. The majority of surveyed companies confirmed the existence of these wastes in their construction projects and acknowledged their impacts on projects cost, quality, and speed.
As only 32% of the surveyed companies were found to be familiar with and using lean techniques, the majority emphasized the need for a practical framework for adopting lean techniques. To help the industry in the further establishment of lean practices, the study addressed 18 main causes of construction wastes, analyzed the extent and impacts of 23 lean techniques, and discussed the practical aspects of adopting a framework for lean construction in AD construction industry. The paper also recommended the assessment of a set of LC-KPIs to measure and guide improvement (in terms of project quality, cost, speed, value and waste) at the end of each “look-ahead” planning period. Worker incentives in a reward system are also recommended to achieve lean construction objectives. The results of the study will be shared with the AD construction industry to get feedback and provide the industry with a starting point for further adoption of lean construction practices.
Directions for future research include addressing the identified causes of wastes and tracking their root causes to existing business practices in scoping, planning, and decision making as well as to the labor issues such as training, language barriers, and cultural aspects. Future research could also focus on providing guidelines for construction managers for addressing quality concerns, enhancing and testing the assessed LC-KPIs including the addition of a safety indicator, and quantifying the costs and gains of adopting the lean construction framework.
Want to talk Lean Construction for Sage 100 Contractor or Sage 300 CRE? Mark Jensen is LAI’s resident SME for Lean Practices! Call him at 480-423-8300, and mention this blog post.
Did you like this blog post? This article was written for the Ledgerwood Associates monthly newsletter. To receive your copy in your inbox, sign up here.