A quantity structure is the agreed quantitative basis of a planning project. It does not merely state an annual volume: it translates sales or production programmes into the figures planning actually works with — products, variants, lot sizes, orders, process hours, transports, stock, shifts and peaks. The term used here is the one VDI 5200 Part 1 uses in its own English text.
Which figures belong in it
| Level | Typical figures |
|---|---|
| Market and product | Product families, variants, sales and growth scenarios |
| Process | Routings, processing times, scrap, lot sizes |
| Logistics | Transport lots, load carriers, sources, sinks, stock |
| Operation | Shift model, availability, performance rate, season and peaks |
Where the quantity structure sits in the planning procedure
The quantity structure is not a preliminary exercise but a phase of its own. VDI 5200 Part 1 structures a factory planning project into seven phases; the second, establishment of the project basis, is concerned with gathering or generating the data and information required for the planning work.
The guideline states the aim of that phase precisely: to formulate a task definition precisely stated from the point of view of factory planning, whose objectives can be checked against the planning data for feasibility. That is the sentence worth keeping. The quantity structure is not there to describe the factory. It is there to establish whether the objectives set in phase one can be reached at all.
Step one: procurement of information
The main task is data collection, and the guideline puts it on three pillars — product data, production data and real-estate data. It calls for data on quantity structures, operating resources and production processes as well as buildings and estate, and it splits the work in two directions:
- Backwards, the necessary current data are secured and the restrictions that apply are determined.
- Forwards, information about the type, quantity and specifications of the products to be manufactured in the years ahead is deduced from forecasts, and assumptions about the processes and resources these require are made — and verified.
The guideline adds the condition under which the future half of that work holds: provided the corresponding scenarios are prepared, different future developments can be taken into consideration in the planning data. A single forecast line is not a planning basis. The planning data obtained are then to be summarised and presented in a structured fashion; the result of the step is the totality of planning data.
Step two: evaluation of information
The second step serves to generate the planning basis and to check the feasibility of achieving the factory objectives defined in phase one. For this, the planning data are to be compressed and evaluated with regard to the factory objectives. The result is that all evaluations concerning those objectives are available as the planning base.
Two consequences follow for practice. The first is that raw data are not a quantity structure — compression against a stated objective is what turns one into the other. The second is that this phase can end with a finding nobody ordered: the objectives set in phase one are not reachable with the data available. The guideline provides for both steps to be run through sequentially and, if necessary, iteratively. A project that treats the data phase as a one-way street has removed the loop the method depends on.
Quality rules
- Every figure carries a unit, a period, a source, a status and an owner.
- Base case, growth case and stress case stay separate.
- Mean values are not dimensioned without a peak profile.
- Totals are reconciled between sales, production, logistics and controlling.
How a sound quantity structure is built
- Set the system boundary: site, areas, product groups and the process stages under consideration.
- Bring the sources together: sales planning, ERP master data, routings, stock and shift calendars on one common status.
- Harmonise the units: pieces, orders, load carriers, hours and transports linked through documented conversion factors.
- Build time profiles: annual figures broken down to months, weeks, shifts or the relevant peak windows.
- Release the scenarios: assumptions, ranges and decision points agreed with the responsible departments.
What matters throughout is the separation of demand, required capacity and technical sizing. A rising annual volume does not automatically call for proportionally more area or staff. Lot sizes, shift model, plant performance, availability, scrap and inventory strategy all govern which resources are actually needed.
Averages, peaks and scenarios
An annual mean can conceal a daily or shift peak. A quantity structure fit for planning therefore carries, besides the base case, at least one realistic growth scenario and a justified load case. Seasonal fluctuation, ramp-up curves, product changeovers and exceptional single orders are marked visibly rather than absorbed silently into an average.
For comparisons of variants, every assumption stays versioned. If the sales figure of a product family changes, material flows, process hours, stock and areas are derived again from the same data version. That is what makes it possible to explain why a layout or an investment moved between two planning states.
Securing an approved data status
A documented data status is released before concept planning begins. The release does not mean every figure is final. It confirms that sources, open points and ranges are transparent enough for the next decision. Later changes carry a date, a reason and their effect on results already calculated.
A compact handover table helps: figure, unit, base year, planning horizon, scenario, source and departmental ownership side by side. For critical assumptions, a date by which they must be settled is fixed as well. The quantity structure then stops being a spreadsheet and becomes the shared, checkable language between sales, production, logistics, finance and planning.
The quantity structure feeds dimensioning, factory area planning, material flow analysis and warehouse planning. The seven phases around it are set out in VDI 5200 and factory planning.
Source
VDI 5200 Part 1 "Factory planning — Planning procedures", edition 2011-02, issue German/English, Section 5.2 with 5.2.1 and 5.2.2. The English wording quoted here is the guideline's own; its title page records that the German version is the authoritative one.
Quantity structure in practice: Our services overview brings together the relevant planning and consulting approaches.