accurate enough to project total facility space needed for each phase of
Allocate space to the
More accurate estimation demands
drilling further into the data. At any
given time a plant typically has a single
bottleneck Element that limits output.
Variations in equipment utilization,
product mix, employment, overtime,
and capital investments can cause bottlenecks to shift. The layout team’s job
is to determine each Element’s current
maximum capacity given the proposed
product mix and operational policy.
The Element with the lowest maximum capacity is the first bottleneck.
The team then develops an action
plan for breaking that bottleneck
and meeting the first phase’s capacity
target. If that Element requires more
area, the addition is recorded in a
new column for phase 1 in the Space
Planning Worksheet. Note that growth
may require more than one Element to
achieve a phase’s capacity target.
If so, those affected Summaries
must also be updated to document
the necessary space and equipment
additions. That exercise is repeated as
growth encounters bottlenecks one by
one. The needs of each bottlenecked
Element are re-evaluated, and the
layout team formulates an action plan
for each phase. In all cases the new
requirements are recorded on the
relevant Process & Support Element
Summaries, and the new space need is
noted in the rows of a new column of
the Space Planning Worksheet.
Layout textbooks call the above
technique converting: Estimating each
Element’s resource needs for the plan’s
phases, extrapolating the new square
footages for each phase, and setting a
space budget. If your project envisions
new product or process capabilities,
new Summaries documenting these ad-
ditions must be created. In all cases the
space estimates from both the existing
and new Summaries should be added to
the Space Planning Worksheet.
The initial resource and space projections for each Element should be developed by a small, experienced team
including an ad hoc representative of
the subject Element. Based primarily on interview and observation, this
method is admittedly subjective.
For that reason the Element team’s
work should be reviewed by the layout
planning team who can consider all
possible improvements in the plant’s
processes whose implementation
impacts space. Lean manufacturing
and execution systems that reduce
throughput time are good examples.
Installation of racks and narrow-aisle
fork lifts that utilize the plant’s clear
height is another.
1. When projecting process
equipment capacities the team must
establish realistic utilization factors.
Overestimating a critical machine’s
run time percentage can doom a
plant to permanent overtime and even
2. Increases in capacity and space
are rarely a linear function of production volume.
3. For Elements that contain large,
complex equipment such as finishing
lines and rough mill systems, space
allocation and configuration should be
based on first-draft detailed layouts.
Balance existing and
The final Space Planning Worksheet
shows the total space estimate required
to manufacture the planned products
and volumes and the allocations to
each Element. Comparing that total
with your plant’s existing area under
roof tells you if sufficient space is available to achieve your target output.
If not, you must determine whether
your site can accommodate one or more
expansions that cure the shortage. If
so, your choices are to expand or scale
back the original capacity target. In
either case, you must repeat the analysis
presented in this four-part series.
Get it right
Starting with the definition of the products to be made, the analysis outlined
in this four-part series provides an
in-depth understanding of your production process, its flow intensity, handling
cost, the relationships between process
steps, and space allocation. Without this
information rationalizing your layout
becomes simply a drafting exercise.
New infrastructure like dust extraction
and other utilities as well as necessary
building modifications are expensive.
You only get one shot at implementing a
The unstated motto of every successful layout planning team is “plan your
work and work your plan.” Over the
course of many projects, the planning