Factory design: writing the brief the building has to satisfy

The brief is a commercial document that happens to be technical

Output horizon, product families, shift pattern, growth assumptions and the tolerance for disruption during expansion are commercial choices. They belong to the people accountable for the business rather than to the design team. Hand a contractor an unstated brief and they will infer one, usually the leanest shell that satisfies building regulations, because that is what they are rewarded for. The useful discipline is writing the brief as a list of things the building must permit — this process on this floor, that machine installed without structural work, that extension built without stopping production — and having the board sign it before anyone draws a line.

Separating what becomes structure from what stays fit-out

Some decisions are effectively permanent: the column grid, the slab, usable height, drain positions and the point where services enter the envelope. Others — partitions, benches, mezzanine offices, small service runs — can be changed over a weekend. Because the cost of getting those two groups confused is wildly asymmetric, the brief should handle them differently, spending argument time on the permanent set and tolerating rough answers elsewhere. A recurring failure is exhaustive debate about office finishes while slab and height are left to a default, which then quietly rules out a share of the equipment the plant will later want to buy.

Buying option value deliberately rather than by accident

Flexibility costs money and its value is not spread evenly. Extra height across the whole footprint, a stronger floor everywhere, or spare electrical capacity for a load nobody has named all consume budget now against a benefit that may never arrive. A better approach identifies where uncertainty is genuinely high — usually the process hall, rarely the administration block — and buys headroom only there, recording the assumption so a later team knows what exists and why. Undocumented spare capacity gets absorbed by the first project that notices it, and the option vanishes without anyone consciously spending it.

Where the brief stops and qualified engineering starts

Nothing written in a brief is a design. Structural capacity, electrical distribution, mechanical services, pressure equipment, ventilation and fire strategy are the work of chartered or licensed engineers applying the codes in force at that address, and their conclusions govern regardless of what the brief hoped for. The brief states what the business needs the building to permit, in terms an engineer can price and test: this equipment installed here, that material handled there, this extension possible without demolition. Trouble starts when a wish list gets treated as a specification, or when a specification is drafted by someone carrying no professional liability for it.

The running costs the design fixes before the plant opens

Once the shell is up, a large share of annual spend is already determined: how far material travels, the volume that has to be heated or cooled, the number of handling moves, the ease of extracting a machine for overhaul, and whether maintenance can reach equipment without a shutdown. None of that shows up in the capital comparison that decides the project, which is why the least expensive shell so often becomes the most expensive plant. Ask for annual operating consequences alongside the build price, even in rough terms, and make the choice on both figures together.

Frequently asked questions

Who should own the factory design brief?

Someone accountable for the plant's output and cost, rather than for the construction budget — usually the operations or manufacturing director, supported by process engineering. Construction project managers optimise for delivery on programme and on budget, which is their job, but they carry no exposure to how the building performs for the following decades. The owner needs authority to refuse value engineering that removes capability, and needs to record why each permanent requirement exists so it survives the cost-reduction rounds that always come.

How much spare capacity should we build into a new factory?

No general figure applies, but a usable method does. List the permanent items separately from the changeable ones, then buy headroom only on the permanent list. Usable height, floor capacity, incoming electrical supply and land for extension are the usual candidates, because adding them afterwards is disruptive or impossible. Air compressors, partitions and mezzanines can be installed later at modest cost, so paying for them early rarely pays back. Write the assumption down so the headroom is not silently consumed.

Is adapting an existing building a reasonable alternative to a purpose-built factory?

Often it is the better commercial answer, provided the assessment runs against the same brief. The questions are whether usable height, floor capacity, services and vehicle access permit the process without structural work, and what a landlord will allow you to alter. Surveys by qualified engineers belong before heads of terms rather than after, because the cost of discovering a hard constraint once you are committed to a lease falls entirely on the tenant.