Workplace Layout Analysis
Workplace layout analysis examines the physical space where a process runs: a workshop, an assembly line, a warehouse, a laboratory. On the floor plan the analyst follows the path of material and people from one station to the next and records the motion, the transport and the waiting that the layout imposes. Its instrument is the spaghetti diagram, the product's path drawn on the plan as one continuous line. The BPM CBOK ties the technique to lean. The analysis needs a physical flow: where work moves only through software tools, it has nothing to draw.
Goal
Workplace layout analysis studies how the arrangement of a workplace lengthens a process. ABPMP's BPM CBOK describes it as a mainly physical analysis of a workplace, an assembly line or a manufacturing floor. It places the technique in the section Analyzing Human Interactions, within process analysis.
The analysis measures how much of a process's time and effort comes from the space rather than from the work. The CBOK takes the method from lean and names three targets: unnecessary motion, waiting and transport. It also names what the analysis finds where work passes from one location to another: material-related bottlenecks, disconnects between stations and duplicated effort.
The deliverable comprises the current-state spaghetti diagram, the future-state diagram and a path log that ties each path to a waste. It supports layout decisions: move a station, bring two steps together, put a tool within reach.
Value stream mapping is its counterpart for the whole end-to-end flow. It follows material and information along the chain and measures the waiting between steps. Layout analysis works on the floor plan of a single site and locates the paths and the waits on it.
Usage
When to use it
- Workshop, assembly line or warehouse: material moves from station to station; follow its path on the plan.
- Physical handoffs outside the factory: laboratory, kitchen, hospital ward, incoming mail, wherever an object passes from hand to hand.
- Planned refit or move: measure the current paths before the new plan is settled.
- Staff who complain of fatigue or long walks: bending, reaching and walking to finish a task signal motion waste.
- Waiting at the handoff between two rooms, found by value stream mapping: look for the cause on the floor plan.
When not to use it
- Knowledge work with no physical flow: the work moves through tools and messages; map the flow with value stream mapping or process analysis.
- A site that does not exist yet: there is no path to observe; design the layout from the relationships between activities and the floor space they require.
- A queue in front of one saturated station: the station's capacity sets the throughput; run a resource allocation analysis.
Description
What the analysis observes
The analyst works on a floor plan drawn to scale. The plan shows the stations, machines, shelving, doors and fixed points, what cannot move without building work: water connections, special power outlets, fume hoods, emergency exits. On it the analyst follows the material flow, the path of parts, products or documents from one station to the next. The analyst also follows the movements of people who fetch, carry and wait. Each passage from one location to another is a handoff.
The three wastes it targets
The CBOK's three targets belong to the seven wastes (muda) that Taiichi Ohno classified: overproduction, waiting, transport, overprocessing, inventory, motion and correction. The analysis deals with three of them because the layout of the stations produces them. The table takes the definitions of the Lean Enterprise Institute (LEI) and relates them to the plan.
| Waste | LEI definition | What the plan shows | Layout change |
|---|---|---|---|
| Motion | The operator makes awkward or unnecessary movements, such as looking for parts, tools or documents. | Round trips by a person to a cabinet, a printer or a stockroom. | Put the tool or the part within reach. |
| Transport | Parts or products move without need, for example from one step to a warehouse and then to the next step. | Long lines between two successive steps, lines that cross. | Place the next step beside the previous one. |
| Waiting | The operator stands idle while a machine runs, while equipment breaks down or while a part fails to arrive. | No line: the minutes noted at the point of waiting. | Bring the stations closer so that the person moves another job forward during the cycle. |
The spaghetti diagram
The LEI defines the spaghetti diagram (spaghetti chart) as the line that traces the path a product takes through the steps of a value stream. The name comes from its look: in mass production this path often resembles a plate of spaghetti. The analyst draws the path on the plan without lifting the pencil, one line per tracked object. The length of the line measures the transport. Its crossings and backtracks show the breaks in the flow. The same drawing made for a person shows the motion waste.
Running the analysis
- Choose the tracked object. A product family, a type of case file, a type of sample, followed from end to end. Two families with different paths give two diagrams.
- Prepare the plan. Start from the floor plan or survey the room with a tape measure. Mark the fixed points, which the future state must respect.
- Observe on site. Lean calls the place where value is created the gemba and bases improvement on direct observation of that place. The analyst follows the object through one full cycle and draws each movement as it happens. The analyst notes every handoff and times every wait in minutes. Without a tape or a measuring wheel, the analyst calibrates their stride over 10 measured metres, counts the distances in strides and converts them to metres. The path log covers the cycles of an ordinary day, peak included, on every shift if the site works in shifts. For how to run a visit, see the observation technique.
- Classify each movement. The LEI distinguishes value-creating work (welding, drilling, painting), incidental work, which the operator must perform without creating value for the customer (picking up a tool, clamping a fixture) and waste, which creates no value and can be eliminated (walking to fetch a part that could sit within reach). Each waste recorded belongs to motion, transport or waiting.
- Look for causes at the handoffs. Does stock pile up at the handoff point? Does the material wait there for a signal that comes late? Do two people repeat the same operation there, counting, checking or labelling?
- Redesign the layout. Bring successive steps together, put tools and parts within reach, remove the detour through an intermediate store. Grouping steps scattered across specialised workshops into one cell removes transport and intermediate stock.
- Draw the future state and try it out. Draw the spaghetti diagram of the new plan and put a figure on the difference per day: the metres saved per cycle times the number of cycles, then the minutes of waiting saved times the same number. Before moving a machine, try the layout out on the floor with the people who work there.
Pitfalls
Drawing from the desk. A plan drawn from memory shows the intended path. Detours, searches for tools and waiting show up only under observation.
Measuring distance alone. Waiting leaves no line on the plan. The analyst notes the minutes of waiting at the point where they occur.
Mixing several objects on one line. The product and the person who carries it follow different paths: the person walks back empty-handed. One colour per tracked object keeps the diagram readable.
Forgetting the fixed points and the rules of the site. A water connection, a fume hood, a separation between clean and dirty areas or an emergency exit stays where it is. A future state that ignores them cannot be built.
Letting people believe that they are being measured. The analysis concerns the site and the flow. The analyst says so before the first observation and shows the diagram to the people observed. Otherwise they walk less during the visit and the path log describes a day that does not exist.
AI considerations
A language model transcribes a handwritten path log into a spreadsheet; the spreadsheet adds up and recalculates each variant. From a dimensioned plan and the list of fixed points, an optimisation tool proposes layouts that reduce the distance travelled. The analyst compares several of them before the floor trial. Computer vision tracks the path of a trolley or a bin on video.
These tools miss what the plan does not show: the shelf placed there for a hygiene reason, the detour that avoids a fire door, the habit that compensates for a recurring breakdown. The analyst validates each proposal on site with the people who work there. The analyst also checks each transcribed distance against the path log on paper. Filming staff to track their movements touches on employment law: art. 26 of OLT 3 prohibits surveillance or monitoring systems intended to monitor the behaviour of workers at their workplace. Its para. 2 requires that a system needed for other reasons be designed and placed so as to preserve their health and their freedom of movement. The camera therefore follows the material, a bin or a trolley, and the analyst informs the team before any filming.
Examples
A medical laboratory processes racks of blood tubes: reception, registration and labelling, centrifugation, testing on the analyser, archiving in the refrigerator. The tracked object is one rack. Each segment of the path is tied to a waste and to a layout change.
Current state · 58 m
Future state · 16 m
| Segment | Current | Waste | Layout change | Future |
|---|---|---|---|---|
| Reception → registration | 4 m | Unavoidable transport | Registration station moved next to the centrifuge | 8 m |
| Registration → label printer in the neighbouring office, round trip | 18 m | Motion | Printer placed on the registration station | 0 m |
| Registration → centrifuge | 14 m | Transport | Registration station set against the centrifuge | 3 m |
| Centrifuge → analyser | 12 m | Transport | Centrifuge placed beside the analyser (fixed point: water supply) | 3 m |
| Analyser → archive refrigerator | 10 m | Transport | Refrigerator under the analyser's bench | 2 m |
| Technician idle in front of the centrifuge | 10 min per cycle | Waiting | Next rack registered during the cycle | 0 min |
| Total per rack | 58 m | 16 m | ||
| Total for 30 racks per day | 1'740 m | 480 m |
One segment gets longer: reception → registration goes from 4 to 8 m, because registration now sits against the centrifuge, which in turn sits beside the analyser that stayed in place. The path log judges the layout on the total: 58 m, then 16 m per rack.
Visualisations
On the spaghetti diagram an arrow marks the start and a number the order of the stops. The current state and the future state sit side by side, on the same plan and at the same scale: the reader sees the difference in length without calculating it. The diagram and the path log in the example apply these conventions.
Cost
| Phase | Level | Justification |
|---|---|---|
| Preparation | Low | The analyst chooses the tracked object, obtains or surveys a plan to scale and announces the exercise to staff. |
| Execution | Medium | The analyst follows the cycles of an ordinary day on site, on every shift, and measures the paths as they happen. |
| Documentation | Low | Two diagrams on the same plan and a path log. After each refit, a new path log is enough. |
Tools
A printed plan to scale, coloured pencils and a pedometer are enough to keep the path log. A measuring wheel gives the distances when the plan carries no dimensions. A spreadsheet holds the path log and totals the variants. Visio and diagrams.net offer shape libraries for floor plans and are used for the clean drawing and the variants. The floor trial needs masking tape and cardboard cut-outs the size of the equipment.
Sources
- ABPMP, Guide to the Business Process Management Common Body of Knowledge (BPM CBOK), version 3.0, §4.6.4 Workplace Layout Analysis: the definition of the technique, the reference to lean, the three targets (motion, waiting, transport), the findings at handoffs between locations and the application to processes that run in a physical space.
- Lean Enterprise Institute, Spaghetti Chart, Lean Lexicon: the definition of the spaghetti diagram and the origin of its name.
- Lean Enterprise Institute, 7 Wastes, Lean Lexicon: the seven wastes classified by Taiichi Ohno; the definitions of motion, transport and waiting; the distinction between value-creating work, incidental work and waste.
- Lean Enterprise Institute, Waste, Lean Lexicon: the waste that cannot be avoided in the current state and the grouping of scattered steps into one cell.
- Lean Enterprise Institute, Gemba, Lean Lexicon: the definition of gemba and improvement based on direct observation of the workplace.
- Swiss Confederation, Ordinance 3 to the Employment Act (OLT 3 / ArGV 3) (Health Protection), SR 822.113, art. 26: in para. 1, the prohibition of surveillance or monitoring systems intended to monitor the behaviour of workers at their workplace; in para. 2, the requirements for systems needed for other reasons.