Six hands, and one record survives.

What this is not

Interfaces Week 17 also followed one drawing and found six holders. That was six firms holding the same revision at the same moment, and the failure was a boundary: you can issue across an organisational line and you can't withdraw across it.

This is the other axis. One organisation is enough. The six hands here are separated by time rather than by contract, and the failure is not that the drawing arrives in the wrong place. It's that a decision was made at each stage, the drawing records only the result of it, and the next hand receives the result with the reasoning removed.

Which is the whole of this track compressed into one week. Seven tracks have taught what to do with a document once it is in front of you. None has shown that by the time it reaches you it is the output of a sequence, and that what you can recover about that sequence depends entirely on which records were born along the way.

The first two hands, and the constraint nobody wrote down

Hand one is the concept layout. The line is approximate, and everybody involved knows it is approximate. But the estimate built on it is not marked approximate for long: it becomes the number in the business case, and the business case becomes the sanction.

Hand two is the detail designer, appointed after award, who opens the concept layout and finds the pump house sitting eleven metres from a boundary. They don't know whether eleven metres was a judgement, a measurement, or a place the cursor stopped. The drawing doesn't say. So they treat it as given, because treating it as arbitrary means reopening a layout that a capital estimate depends on.

An assumption has now become a constraint, and the transition happened without anybody deciding it. That's the mechanism this track keeps meeting: the front end hands forward its conclusions and discards its reasoning, and the delivery team inherits conclusions that have hardened on the way. Nobody wrote the assumption down, so nobody downstream can tell that it is one.

The third hand — a dimension leaves the drawing

Procurement takes a nozzle centreline off the issued drawing and puts it in a requisition. The requisition becomes an enquiry, the enquiry becomes an order, and at the moment the order is placed that dimension stops being a drawing and becomes a commitment with a delivery date and a price.

Nothing was copied incorrectly. But the dimension now exists in two places that are maintained by two departments on two revision cycles, and only one of them is on the drawing register.

The fourth hand — the vendor sends back a drawing that outranks yours

The vendor returns a certified drawing. It's close to the enquiry and it isn't identical, because the machine they actually build has a different base plate.

The certified drawing is correct and it takes precedence — that's what certification means. What the vendor has manufactured is what will arrive, and the design has to move to meet it rather than the other way round. Everybody involved understands this.

The vendor drawing goes to the discipline that raised the requisition. It reaches mechanical engineering, who accept it, mark up the general arrangement and reissue.

The foundation is civil. Civil engineering was never on the vendor's distribution, because civil never raised a requisition. The bolt pattern reached one discipline and stopped.

The fifth hand — the change travels backwards

Site finds it. Concrete is in, the holding-down bolts are set to a pattern that no longer matches, and the query that goes back up the chain is the first document in the sequence that travels in the opposite direction to everything before it.

And this is the point where the sequence starts producing the records this site has spent seven tracks on. A technical query, then an instruction, then a variation, then possibly a claim. Claims Week 2 takes the causal chain apart properly; what matters here is where in the life of the project it was born, and the answer is four hands upstream, in a distribution list that was drawn by department rather than by consequence.

Nobody here was careless. The vendor drawing correctly outranked the design. Mechanical correctly accepted it. The distribution list correctly reflected who had raised the order.

The sixth hand — and the only record the owner keeps

At the end the as-built is compiled: the drawing as the thing was actually built, bolt pattern corrected, dimensions reconciled.

Of the six records in this sequence, it is the one that outlives the project. The concept layout is in a study nobody reopens. The requisition is in a procurement system that will be decommissioned. The technical query is in a register that closes with the final account. The operator who runs this plant for thirty years will have the as-built and the operating manual, and that is the whole inheritance.

Which puts a question under the last week of this track and worth carrying from the first. An as-built that records the dimension tells the operator what is there. An as-built that also records that the dimension came from a vendor certification, and which one, tells them why it is there and what has to change if the machine is ever replaced.

The second is a record. The first is a picture.

System design

Six records, one per hand, and the data dictionary this site has been building across two tracks now extends to a whole project rather than to a function. Read the Required quality column down the page: in every row it asks for the same thing, which is that the record carry its own provenance.

Record	Produced by	Required quality	Verified against	Feeds
Concept layout & basis of design	Feasibility team, before award	States which dimensions are judgements and which are measured	The estimate built on it	Every layout decision downstream
Issued-for-construction drawing	Detail engineering	Revision reason recorded, not just revision letter	The concept it developed	Construction · procurement · the as-built
Requisition and order	Procurement, from a drawing dimension	Carries the drawing and revision it was taken from	The issued drawing at that date	Delivery date · committed cost
Vendor certified drawing	The vendor, after award of the order	Distributed by consequence, not by who raised the order	The enquiry it answers	Foundations · connections · the as-built
Technical query and instruction	Site, travelling upstream	Names the drawing, the revision and what was already built	The physical work in place	Variation · claim · the as-built
As-built record	Document control, at closeout	Records where each dimension came from, not only what it is	The thing as constructed	Operation · maintenance · replacement

The last row is the one that decides whether the other five were worth producing. Everything above it is discarded at closeout, so whatever the as-built doesn't carry forward is lost when the project team disperses.

Practical insight

Take one drawing your current work depends on and walk it backwards rather than forwards. Find the revision before the one you are holding, and the reason it changed.

You'll hit a wall, and where you hit it is the useful part. At some revision the trail stops being a document and starts being a person — somebody who remembers a meeting, or a call with a supplier, or a decision taken in front of a screen. That's the point where no record was born, and it marks the boundary of what your project can still explain about itself.

Do the same on your own outputs for one month. Every time you issue something that changes what somebody else will build, ask whether the reason is recoverable from the document or only from you. Where the answer is only from you, add one line. Not a procedure — one line, in the transmittal or the revision note, saying what changed and what drove it.

It's the cheapest thing in this entire track and it is the difference between a project that can be reconstructed and one that can only be remembered.

Key takeaways

• The drawing that reaches site is the output of a sequence, and each hand in it saw one step in either direction at most.
• A document carries the result of a decision. It rarely carries the reasoning, and the next hand receives the result with the reasoning removed.
• An approximate line becomes a fixed constraint the moment an estimate is built on it, and nobody decides that transition.
• When a dimension moves from a drawing into an order it starts living in two places on two revision cycles, and only one is on the drawing register.
• A vendor certified drawing outranks the design correctly. What fails is the distribution, which is drawn by department rather than by consequence.
• The query that comes back from site is the first document in the sequence travelling upstream, and it is where the commercial records begin.
• Of the six records born along the way, the as-built is the one the owner keeps. The rest are decommissioned with the systems that hold them.
• An as-built that records only the dimension is a picture. One that records where the dimension came from is a record.
• Ask which record is born at each stage. Where none is born, that stage can't be reconstructed later — only remembered.

Records born here. The concept layout and its basis of design · the issued-for-construction drawing · the requisition and the order raised from it · the vendor certified drawing · the technical query and the instruction answering it · the as-built record.

What is coming next

One drawing, six hands, five years. The next question is where the five years came from, because the answer is not the same for everybody on the job.

Ask an owner when the project started and they will name a board decision. Ask the designer and they will name the day they decided to propose. Ask the contractor and they will name the day they decided to bid. Three parties, one project, three different first days — and the delivery team's day one lands in somebody else's third year.

That's where this track begins properly: before anybody was appointed.