A Study of Lean Construction Practices in Gaza Strip

for measuring the percent plan complete (PPC) and look for the causes of failure. In
addition, PPC also helps to reduce the variation.
2.5.4 Cycle time reduction
The cycle time is the time required for executing the process traverse the construction
flow. The cycle time is used to measure the flow processes and it is a more useful than
cost and quality. It can be represented as follows:
Cycle time = Processing time + inspection time + wait time + move time
The new construction philosophy aims to compress the cycle time, which forces the
reduction of inspection, move and wait time.
In addition to the forced elimination of wastes, compression of the total cycle time gives
the following benefits: faster delivery to the customer, reduced need to make forecasts
about future demands, decrease of disruption of the construction process due to change
orders, easier management because there are fewer customer orders to keep track of.
The principle of cycle time compression also has other interesting implications:
1. From the perspective of control, it is important that the cycles of deviation detection
and correction be speedy.
2. In design and planning, there are many open-ended tasks that benefit from an
iterative search for successively better (if not optimal) solutions. The shorter the
cycle time, the more cycles are affordable.
3. From the point of view of improvement, every layer in an organizational hierarchy
adds to the cycle time of error correction and problem solving. This simple fact
provides the new construction philosophy’s motivation to decrease organizational
layers, thereby empowering the persons working directly within the flow.
Practical approaches to cycle time reduction include the following: Eliminating workin-progress
(this original JIT goal reduces the waiting time and thus the cycle time),
reducing storing time and setting temporary stores so that moving distances are
minimized, thus keeping things moving; smoothing and synchronizing the flows,
reducing variability, changing activities from sequential order to parallel order, and
eventually isolating the main value-added sequence from support work. In general,
solving the control problems and constraints prevents a speedy flow.
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