1 Office Space Requirements
Dec 19, 2015
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Office Space Requirements
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Universal Axioms
Manufacturing managers in large companies tend to overestimate their individual cell or departmental space needs
Manufacturing space is like a closet, clutter will continue to collect until it fills the space provided
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General Considerations No magic formulas to follow Experienced managers will overstate
their requirements Inexperienced managers will understate
their requirements Main aisles in a light manufacturing
plant will account for approximately 10% - 18% of total under roof floor space
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The Big Three Budget Limitations
1. Cost Limitations
2. Schedule Limitations
3. Human Resources Limitations
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Gross Business Ratios Space versus sales ratios Revenue ratio Plant ratios or ratio ranges
Estimate data for large companies Use public domain information Office area is fairly consistent Manufacturing size varies by type (cellular,
assembly line, etc.)
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Space-Related Ratios
Total Production Space
Number of Production WorkersSpace-related Ratio =
Useful for existing plant expansion . . .
Take note of the current working conditions:
• Congested = “worst” case scenario
• Functional = “optimal” scenario
Baseline the expansion on these numbers
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Space-Related Ratio Example
A local manufacturer has determined the following:
• Space is considered “tight”
• They have 50 employees
• They currently occupy a 5,000 sq. ft. facility
• Expected 5 year growth = 75 employees
What do we know?
Employee / Space Ratio = 5,000 / 50 = 100 sq. ft / employee
Anticipated facility size in 5 years = 75 X 100 sq. ft.
= 7,500 sq. ft.
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Ratio Caution A ratio is like a forecastforecast. . . it’s only
an estimate of the future Review the past sales / production
history Review the economic conditions
during the growth periods Use the ratios as a guide
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Space Balance Analysis
Most often used classifications: Primary operations Secondary operations Inspection and test areas Storage areas
Raw materials WIP Finished goods
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Space Balance Analysis Service and support
Maintenance Tool cribs
Shipping / Receiving dock areas Offices Aisles
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Space Utilization
Space Utilization
7% 8%
12%
17%17%
19%
20%Service / Support
Molding
Offices
Light Assy
Aisles
Shipping / Receiving
Warehouse
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Site Saturation Planning Completely utilized configuration
No room for building additions No room for expansion
Framework for master facility plan Estimates are derived for
maximum facility layout Used to determine maximum
production output on existing site
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Site Saturation Planning Completely utilized configuration
No room for building additions No room for expansion
Framework for master facility plan Estimates are derived for
maximum facility layout Used to determine maximum
production output on existing site
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Site Saturation PlanningNeglecting site saturation
planning can result in long-term consequences costing the
organization significant capital
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Equipment Utilization Consideration
Equipment utilization impacts layout space
Don’t plan on 100% equipment utilization levels
Take PFD into consideration Rely on historical data including
utilization and maintenance
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Equipment Utilization Consideration
Example:
• Equipment currently runs at 65%, producing 500 pcs./day
• OEM states production runs of 769 pcs./day
• Growth projections require 1,300 pcs./day
• Management expects 85% utilization through improvements
How many machines are required to meet production growth?
(500 pcs./day X 85%) / 65% = 653 pcs./day
1,300 / 653 = 2 machines required [negligible OT projected]
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Adjusting Today’s Needs Also known as conversion or
converting Tally all currently used space Calculate the space for aisles Interview and observe the workers Collect data from the workers Confirm and correct estimates Base projections on the data
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Adjusting Today’s Needs – From the Trenches
Space required for increasing capacity or production levels in not linear
The Conversion methodology uses a subjective or approximate approach
Evaluate each situation carefully Used for basic level planning
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Equipment Utilization Consideration
Example:
A walk-through of the existing 1,225 sq. ft. department (operating 24 / 7 @ maximum capacity) indicates congestion. This area could use an increase of 5% - 10% of space. Develop a baseline SWAG of future space allotment if the area doubles in capacity through increased demand.
Using the Conversion method:
(1,225 sq. ft. X 108%) X 2 = 2,646 sq. ft. estimated
Average = 8% Double capacity
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Determining Space Needs Known as a Rough Layout or
Production Center method Detail each piece of equipment
Indicate door swings Special access areas Approximate equipment spacing Utility requirements (water, air, power,
etc.)
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Elements of a Push System
Production Schedule
Assembly Schedule
Processing Schedule
Procurement Schedule
Suppliers
MaterialsWarehouse
ProductWarehouse
Fabrication Assembly
WorkOrders
WorkOrders
In-ProcessInventory
In-ProcessInventory
MaterialOrders
Trigger or process driverInformation flow and material flowInventory managementWork order control vs. visual controlIntegration of suppliers
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Elements of a Pull System
Suppliers Fabrication AssemblyProduct
Warehouse
CustomerDemand
Point of useStorage
In-ProcessInventory
AssemblyUsage
FabricationUsage
Trigger or process driverInformation flow and material flowInventory managementWork order control vs. visual controlIntegration of suppliers
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Pull Production System
In a Pull System, coordinating the production and movement of parts and components between processes is critical in avoiding over production or shortages.
To achieve this coordination, you can use a system called “Kanban.” Kanban is a mechanism for managing a pull production system.
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Kanban Kanbans have been in use in the US prior
to the mid-1960s
One of the most widely used systems before MRP and MRP-II
Requires maintaining minimal inventory levels
Kanban starts at the end . . . Shipping
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Kanban Kanban is also known as “pull”
manufacturing
Kanban loosely translated to “card”
Kanban is a simple visual scheduling and replenishment approach
Kanban signals can be cards, containers, lights, “Poker Chips”, etc.
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Pull Signal CalculationProduction Kanban
An example of a simple pull signal (Kanban) calculation where a constant quantity of product is withdrawn at varying intervals:
K =Dr * Tr * (1+Fm)
Uk
Where:
K = Number of Kanban (number of signals)And:
Dr = Demand Rate Tr = Replenishment Lead Time (for feeder)Uk = Units per Kanban (per signal)Fm = Management Factor (safety factor)
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Pull Signal CalculationSupplier Kanban
An example of a simple pull signal (Kanban) calculation where a variable quantity of product is provided at constant intervals:
K =Dr * (2 + Td) * (1+Fm)
(Uk * Dd)
Where:
K = Number of Kanban (number of signals)And:
Dr = Demand Rate Td = Transit Delay (for supplier)Uk = Units per Kanban (container capacity)Dd = Deliveries per DayFm = Management Factor (safety factor)
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Inventory Convert inventory to physical space terms
Inventory holding costs have a significant impact on the bottom line of a company
Increased production does not directly reflect increased inventory
Reduce inventory where possible
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Inventory
Inventory
Customer OrderLead Time
On-TimeDelivery
CurrentCapability
Do we have to make trade-offs?
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Space Need Pitfalls Ratios and projections are
approximations Many companies guess at
space needs Forecasting errors Overestimating space
requirements Poor understanding of the
manufacturing process
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Questions & Comments