Introduction
Facilities Planning
Lecture 6: Flow, Space, &
Activity Relationships
After gathering data from engineering and
management functions, data analysis and
basic planning is performed:
{
Flow planning
{
Activity relationship analysis
{
Materials, people, equipment, documents...
Department, area, function, workstation, building,
machine
Space planning
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Flow and Activity Analysis
Flow Planning
Analyze the flow of materials,
information, equipment, and personnel
Flow Analysis
Process of arranging activities in combinations of basic flow patterns
(based on flow analysis),
{
{
Quantitative measure of movement
between departments or activities.
Activity Analysis
{
Non-quantitative factors that influence the
location of departments or activities.
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Discrete flow:
Logistic systems:
{
{
{
manufacturing industry, job-shops, machine shops, auto industry.
Materials management
Material flow systems
Physical distribution systems
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Flow Patterns Within
Departments
Flow Patterns
Chemical/process industry - crude oil in pipeline, food grains in food
processing industry
{
Quantitative (from-to chart) and
Qualitative (activity relationship diagram).
Continuous flow:
{
{
2
Hierarchical Decomposition
{
Flow within a workstations
Based on motion studies and ergonomics
Flow within workstation should be
simultaneous, symmetrical, natural,rhythmical
and habitual.
In Product Departments
Flow within a department (intra-cell)
{ Flow between departments (inter-cell)
{
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Flow Patterns Within
Departments...
Flow between departments:
Types of Flow Patterns
In a process department,
{
{
little flow should occur between workstations within departments.
Flow occurs between workstations and aisles.
Horizontal
{
{
{
{
{
{
{
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interactions among workstations
available space
size of materials
{
Ground-level ingress
and egress
{
{
{
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On same side or on
different sides
Decentralized elevation
Centralized elevation
Inclined flow
Bucket or belt
conveyor
Escalator
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Effect of Locations of
Entrances/Exits on Flows
Flow Between Departments
Vertical
Dependent on:
{
Straight-line flow (Iflow)
L-shaped flow
U-shaped flow
Circular flow (O-flow)
Serpentine flow (Sflow)
Flow between departments is often used to evaluate flow
within a facility.
Flow typically is a combination of the basic horizontal flow
patterns shown below.
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Vertical Flow Patterns
An important consideration in combining the flow
patterns is the location of the entrance (receiving
department) and exit (shipping department).
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Effective flow planning involves combining the patterns above
with adequate aisles to obtain progressive movements from
origin to destination.
A directed flow path is an uninterrupted flow path progressing
directly from origin to destination:
{
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Flow Planning
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The figure below illustrates the congestion and undesirable
intersections that may occur when flow paths are interrupted.
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2
Principles of Effective flow
planning
Maximize directed flow
{
{
{
{
{
{
{
Directed flow: uninterrupted flow,
does not intersect others
Eliminate backtracking
Eliminate cross flows and
intersections
Minimize queuing delays
Minimize Pick-Up/Drop-Off
delays
Minimize in-process storage
Minimize transport
Minimize cost of flow
{
{
Reduce travel distance
Eliminate manual handling by
mechanizing or automating to
allow operators to concentrate on
processing
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Flow Analysis
Minimize frequencies of flow
through work simplification
{
{
{
Deliver directly to the point of
use
Eliminate waste, operations
Minimize multiple flows by
moving material directly
between two points in one step,
i.e., avoid double handling
{
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Plan appropriate unit of load,
use pallets to min. Trips
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{
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{
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Flow Diagram
Flow process charts
Multiproduct process charts
{ Flow diagrams
{ From-to charts
{
Provides information concerning the number
of material handling trips made between two
centers of activity and the total material
handling distance
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Multiproduct
process charts
Uses circles,
squares, arrows,
triangles, and D for
operations,
inspections,
transportations,
storages, and
delays, respectively
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Analog models for describing flow
Combine flows and operations
whenever possible, e.g..
Automobile assembly
Flow
Process
Chart
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Combines the
operation process
charts for several
products
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From-to charts
Depicts the
probable
movement of
materials
superimposed on a
floor plan
Quite useful for
evaluating existing
layouts
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3
Measuring Flow
Exercise: Track the Flow
FLOW ANALYSIS -- FLOW x DISTANCE
{
Frequency, from-to chart (# of material
movements)
Product Quantity Load-size # Moves Routing
1
30
3
10
A-C-B-D-E
2
12
2
6
A-B-D-E
3
7
1
7
A-C-D-B-E
{
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Distance
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Organizational relationships
{
{
{
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Activity Relationship CHART
ACTIVITY RELATIONSHIP
{
{
{
{
Shows the closeness
ratings and reasons for
closeness requirements
between activities.
Replaces the from-to
chart with a qualitative
closeness rating
All pairs of relationship
are evaluated and
assigned
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Other relationships
{
Utility requirements
{
Process relationships
{
Foundation & floor
requirements
Floor loadings, water
treatment
Chemical processing,
and special services
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Construction procedure
{
A = Absolutely
Necessary
E = Especially Important
I = Important
O = Ordinary Closeness
U = Unimportant
X = Undesirable
{
{
Safety, health, noise,
fumes, humidity, dust,
temperature relationships
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Activity Relationship CHART
A closeness rating
representing an ordered
preference
Centralized vs.
Decentralized control; level
of control
Frequency of review:
continuous vs. Periodic
Material and inventory
control, shop floor control,
level of automation
{
Environmental relationships
{
Control relationships
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Which function has more
(less) organizational
relationship with another
Reporting/cooperating
relationships
{
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Activity Relationship Analysis:
Qualitative Analysis
Exercise: Find a Better
Arrangement
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{
{
{
A and X > E > I > O > U
All ratings but U are
explained with a numeric
code
{
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List all activities
Conduct interviews and
surveys to obtain closeness
ratings
Define criteria used for
closeness ratings
Establish relationship chart
Assign a closeness rating to
each pair-wise combination of
activities and record the code
for the reason behind the
rating.
General review and
discussion
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Activity relationships are often
translated into proximity
requirements
{
{
{
{
{
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Activities with strong, positive
relationships are located close
together
Activities with strong negative
relationships are separated
Proximity relationships can
sometimes be satisfied without
physical separation
Activities with high information
exchange can be linked with
communication systems
Negative relationships can be
satisfied by enclosing noisy
areas, venting fumes, etc., as
opposed to physical separation
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4
From-To Calculations from
Routings
Activity Relationship Analysis
Construction process of activity relationship chart is
complicated by the multiple types of relationships
that exist
{
{
{
Resource requirements
Environmental issues
Example:
Painting and Sanding have high flow, should they be
adjacent?
Mgmt Offices and Production have high interaction, should
they be next to one another?
Create a separate relationship chart for each one
may be necessary
{
105,219
1,052
For example, a relationship chart might be created for
material flow, personnel flow, and equipment flow.
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For N activities there are
N(N-1)/2 relationships
{
{
{
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Example
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10 activities – 45
relationships
50 activities – 1225
relationships
Rule of thumb, Usually
expect about:
{
{
{
{
{
{
5% A relationships
5% X relationships
10% E
15% I
20% O
>= about 50% U
relationships
Cannot satisfy all
relationships
Satisfy A and X
relationships
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Activity Relationship Diagram
Spatially depicts the relationships between
the activities.
Based on satisfying relationships with
geographic proximity.
{
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However, this may not be the only way to satisfy
“closeness” ratings.
Process often requires compromises if all
closeness ratings cannot be satisfied.
{
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Can overcome this by
grouping areas that have
strong relationships
{
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Activity Relationship Chart Facts
The Relationship Chart
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Furthermore, if a 25-ft separation satisfies a
closeness requirement, does a 50-ft separation
also satisfy the closeness rating?
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The relationship diagram
Design strategies
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An Improved Relationship
Diagram
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Try to place A’s and E’s first to minimize
length of thick relationship lines.
Try to keep lines of same value the same
length
Try to avoid crossing lines, usually indicates
change is possible
Make X’s longest lines
Not every relationship (U) needs to be
shown
Generate multiple alternatives
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Converting Flows to Closeness
Ratings
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Exercise - Develop a
Relationship Diagram
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Perhaps the most difficult
aspect of facility plan
Strategic planning (5-10 yrs) :
{
{
{
{
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Optimal design:
{
{
For future
expansions/changes
Optimize use of space within
feasible range
Criteria of optimality:
Technology changes
Demand forecasts
Changing product mix
Parkinson’s Law
{
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Large amounts of uncertainty
{
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Principles of Space Planning
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efficiency & productivity,
material handling,
cost, and
operator safety & fatigue.
Things will fill available
space sooner than you plan.
New designs (pull systems,
decentralized storage, etc.)
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Elements of Space
Requirements
Work Areas:
{
{
{
{
{
{
{
{
{
{
{
Equipment,
worker,
material storage,
material handling,
tool rooms & cribs,
Maintenance
Quality control &
inspection,
Supervision
Offices
Aisles,
Packaging
Non-Work Areas:
{
{
{
{
{
{
{
{
Receiving and shipping
Restrooms
Health and medical
facilities
Food service
Lavatories, washrooms,
etc.
Employee and visitor
parking
Receiving and shipping
parking
Other storage
Ground-up approach:
{
{
1st form workstations
then departments.
FACILITY
Department
Work Station
...
Department N
...
Equipment
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Space Requirements
{
Use standards based on past successful applications
Used for general space requirements. Establishes a ratio of square
feet to some other factor, such as direct labor hour, units produced,
etc.
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...
Space for:
Templates or models are used to estimate space
Ratio trend and projection method
{
Space-standards method
{
Estimate the space requirements from those required for the present
layout (or a similar one in another facility)
Workstation
specification
(Production-center
method)
Roughed-out layout method
{
Factor determined for a single machine and all the equipment and
space required for its operation. This is multiplied by the number of
pieces of equipment and summed over all equipment types
Converting method
{
Production-center method
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Space Requirements
Workstation specifications:
{
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{
{
{
Equipment,
Materials,
Personnel and
Plant service
{
Try to:
{
Eliminate long and
awkward reaches
Make work efficient
Minimize manual
handling
Maximize operator
safety, comfort and
productivity
Utility lines, vents,
air conditioning
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Space Requirements
Equipment space
/footprints:
{
{
{
{
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Production Rate Determination
{
Market forecast is translated into production quantities
Equipment: Static
width, depth and height
Machine travel: vertical,
left, right, forward and
backward
Machine maintenance
Plant services: utility
lines, vent hood, air
conditioning
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Desired output = On = (1+Safety Factor)*Forecast
For k = n,...,1
where Ik = Production input to operation k
Ok = Production output from operation k
Pk = Scrap rate for operation k
Example
{
{
{
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Three operations, scrap rates 3%, 2%, and 4%
Forecast = 180,000 units per year (plus 10% allowance)
Input quantities are 217.0, 210.5, and 206.25 units per hour to achieve
output of 198 per hour
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Space Requirements
...
Equipment Requirements
Number of machines required for the desired production
rate at each processing stage
{
Receiving and storing materials
In-process materials
{ Storing and shipping materials
{ Storing and shipping waste and scrap
{ Tools, fixtures, jigs, dies, and
maintenance materials
{
Pij = desired production rate for product i on machine j
Tij = production time for product i on machine j
Hij = number of hours available for production, including an
allowance for machine downtime, etc.
Mj = number of machines of type j required
n = number of products
{
Then,
{
Could also use probability distributions instead of point
estimates
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{
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Space Requirements (cont.)
1m ≈ 3.3 feet
Personnel area includes space for
Operator
{
Materials areas include space for
1 foot = 0.3048 m
1 ft2 = 0.0929 m2
1m2 = 10.76 ft2
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{
Material handling
{
Operator ingress and egress
Obtained directly from method of performing the operation determined
by a motion and ergonomic study
Employee Requirements
{
For manual assembly operations, we can use the same method
as machine requirements
{
In some cases, an operator may tend multiple machines
Minimum of 30” (~75cm) aisle for operator travel past stationary objects
Minimum of 36” (~90cm) isle for travel between a stationary object and
an operating machine
Minimum of 42” (~105cm) aisle for travel between two operating
machines.
Assume all times are deterministic
{
{
{
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{
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Use multiple activity chart or human-machine chart
Especially useful for tending non-identical machines
For identical machines, use a prescriptive method that minimizes the total
cost. Tradeoff is between operator idle time and machine idle time.
Assume all times are probabilistic
{
Simulate the operator performing a typical days work to ensure
the adequacy of the space allocation and the efficiency of the
operation.
Use queueing theory or simulation
Might use a pool of operators to serve a group of machines
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Aisle Arrangement
{
{
Aisles too narrow may result in congested facilities, high
levels of damage, and safety problems
Aisles too wide may result in wasted space and poor
housekeeping practices
Curves, jogs, and nonright angle intersections should be
avoided
Aisles should be straight and lead to doors
Avoid aisles along outer wall of building unless for
entry/exit
Aisles along the outside wall should only be used for
entering and leaving the facility
Column spacing should be considered
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Aisle space requirements can not be determined exactly
but the following table can serve as a guide:
If the largest load is
Aisle allowance %*
Less than 6 ft2 (~.56m2)
5-10
2
2
10-20
Between 6 and 12 ft (Upto ~1.12m )
20-30
Between 12 and 18 ft2
30-40
Greater than 18 ft2 (~2.23m2)
Principles:
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{
Objective: promote efficient flow
46
1m ≈ 3.3 feet
1 foot = 0.3048 m
1 ft2 = 0.0929 m2
1m2 = 10.76 ft2
Space Requirements
44
Space Requirements
Obtained directly from method of performing the operation determined
by a motion and ergonomic study
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*: % of net area requirements for equipment, material, and
personnel.
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8
Some Recommended Aisle
Widths
{
Space Requirements
Widths determined by considering the
type and volume of flow :
Department specification
{
May not be the sum of the individual
workstations
{
Some machine maintenance, plant services,
incoming and outgoing materials, and operator
ingress and egress areas may be combined.
Additional space is required for material
handling within the department.
{
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Departmental Service
Requirements Sheet
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Many items are shared from workstation to workstation
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Exercise - Compute the Aisle
Space Percentage
Assume building is 100’ x 100’ and aisles are 10’ wide.
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Space Requirements for NonWork Activities (Chp 4)
Employee Parking:
{
{
{
{
{
{
Dining away from facility:
{
Cafeteria: vending machines, serving line, full kitchen
{
Drinking fountains - within 200 ft (~61 m) of a regular
location
Break areas
{
Within 200 ft (~61 m) of every permanent workstation
15 ft2 (~1.4m2) for toilet, 6 ft2 (~0.56m2) for urinal, 6 ft2 (~0.56m2)
for sink, 15 ft2 (~1.4m2) for entrance;
see table (5.2 and 5.3 for # per).
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{
Locker rooms: 6 ft2 (~.56m2) per person
Between entrance and work area along outside wall
Rest Rooms:
{
Food Services
select the layout that best utilizes space and maximizes employee
convenience
Storage of Personal Belongings:
{
Determine # automobiles, use ratio (1.25 or 1/3)
Determine space required for each car
Determine available space and alternative layouts
Space Requirements for NonWork Activities (Chp 4)
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longer break, lost supervision, concentration & interaction
tray and table size, layout, outside view, etc.
Health Services
{
{
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Examination room, beds, waiting rooms
First aid room
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Homework
Chp 3
3.3
3.10
{ 3.30
{
{
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