The concept of lean production originated from the Toyota Production System and was created by engineer Naiichi Nono.
Lean theory divides all activities in production systems into two categories: transformation activities and flow activities.
Transforming activities into products or processes adds value, while mobile activities (i.
e.
NVA activities) consume time, costs, and resources without adding value.
Previous studies have shown that lean concepts can effectively improve environmental benefits, such as reducing inventory waste, equipment waste, and material waste (Luo et al.
, 2005).
In precast concrete factories, the implicit carbon of precast concrete columns can be reduced by 8% (Wu and Low, 2011a).
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