Lessons · Lesson 2 of 6
The only number you own is the one on your meter
Turn your factory's meter readings into a number that answers a buyer's question. State the unit, state the boundary, and state how you shared the readings out.
Lesson 2 of 6 · 18 min
Three answers to one email
Verlanda has sent Hendek an email. It asks how much water PO VL-9182 uses. The factory can give three answers. Only one of them is worth sending.
The first is a published figure. Somebody forwards a page that gives the water in a cotton t-shirt. The number is large and easy to remember. It is also unusable. Not because it is wrong — it may be careful work. It is unusable because it was not built to answer this question. It answers a question about a different garment, made somewhere else. And it was measured over a boundary nobody has stated in the email. Sending it tells Verlanda nothing about Hendek. It also ties Hendek to a number it cannot defend.
The second is the water bill. Hendek's site meter read 41,600 cubic metres over the twelve months to 31 July 2026. In the same period the factory shipped 1,486,000 garments. Divide one by the other and you get 28.0 litres a garment. It is Hendek's own number. It is measured. It is still the wrong answer. Those 1,486,000 garments include fleece hoodies carrying nearly three times the cloth weight of a polo. They include black bottoms dyed on a route no polo goes near. They include one buyer's programme that ran in a single colour all year. Dividing a site total by a garment count assumes every garment is the same garment. None of them are.
The third is what Hendek actually sends. Building it is the subject of this lesson.
Two questions hide inside "how much water"
Before you give any figure, decide what a unit of the answer is. A consumption figure is a fraction. Every fraction has a bottom number. Choosing that bottom number is a decision.
- Per kilogram of cloth is the honest unit for a dyehouse. A dye machine does not know what garment its cloth will become. What it uses tracks three things: the mass of cloth, how deep the shade is, and how many times the machine is filled. None of those is a garment.
- Per garment is the unit the buyer asked for, because a buyer buys garments. It is a fair question and a fair number. But it is a composite — a number built out of two others. It takes the dyehouse figure and multiplies it by however many kilograms of cloth this particular garment happens to carry.
Both are real. They are not interchangeable. Mixing them up is the commonest error in the whole subject.
Hendek quotes both, side by side. It never sends one alone.
Boundary: where the counting starts and stops
The second decision is where the system you are measuring begins and ends. Hendek's boundary is easy to state, because it is a fence:
From greige yarn entering Hendek's gate, to a packed carton leaving it.
Greige yarn is yarn that has not been dyed yet. Everything inside that fence is on Hendek's meters. Everything outside it is not, and Hendek does not have it. Not the cotton growing. Not the ginning. Not the spinning. Not the transport in. Not the sea freight. Not the shop. Not the washing machine the polo will spend three years in.
Stating that boundary is not a disclaimer. It is the thing that makes the number usable. A number with no boundary cannot be compared with anything. And a number compared across two different boundaries produces a conclusion that is confidently wrong.
Allocation: getting from a site to an order
The last decision is how a shared reading is divided between the orders that caused it.
Hendek's dyehouse water is not shared. Every one of the 60 loads for VL-9182 has its own meter reading in the dyehouse log, with its own date, machine, colour and mass. That is direct measurement. It needs no dividing up at all.
Site services really are shared: the canteen, the washrooms, the boiler make-up water. There is no honest way to meter the canteen against a purchase order. So Hendek divides them across garments shipped, and says that it does:
| Figure | How it was obtained | What it depends on |
|---|---|---|
| Dyehouse water and heat | read for each machine load from the dyehouse log | nothing — it is a direct reading |
| Knitting electricity | sub-meter on the knitting hall, divided by cloth output | how the hall's output is recorded |
| Cutting, sewing, pressing, packing | sub-meter on the making building, divided by garments | the garment mix in that period |
| Site services water | site meter less dyehouse meter, divided by garments shipped | a share-out, stated as one |
The right-hand column is the part most factories leave out. It is also the part an auditor reads first. Two of these four figures rest on an assumption. Saying which two costs nothing. It is the difference between a number a buyer can check and a number a buyer has to trust.
Hendek's answer
| Per kilogram of finished cloth | Per polo | |
|---|---|---|
| Water | 94.07 litres | 29.35 litres |
| Energy | 16.11 kWh | 5.025 kWh |
| Cloth | — | 0.3120 kg |
Both columns come from the same readings. The per-kilogram column divides the order's totals by 13,104 kg of cloth. The per-polo column divides the same totals by 42,000 polos. Neither is more true than the other. But look at what the pair does that neither can do alone. It tells Verlanda straight away that a lighter polo would move the right-hand column and leave the left-hand one exactly where it is. That is the beginning of a useful conversation rather than the end of a polite one.
Check yourselfHendek's per-garment water figure falls from 29.35 litres to 27.9 litres between two seasons, and nothing in the dyehouse changed. What happened?Show the answer
The garment changed. The most likely cause is cloth weight. The second season's polo carries fewer kilograms, so the same per-kilogram process gives a smaller per-garment number. It could also be a lighter range of shades. Or fewer colours, which means fewer machine loads. All three are covered in the next two lessons. What it is almost certainly not is a dyehouse improvement. A factory that reports it as one has made a claim that will not survive the question "which process changed?". This is exactly why the per-kilogram figure is quoted beside the per-garment one.
What you should be able to do now
- Refuse the published average, out loud, with the reason. Not because it is wrong, but because it has no question attached and no boundary you can check.
- State a unit, a boundary and a basis of allocation in the same sentence as any consumption figure you send. Three short clauses. Without them, the figure is not evidence.
- Quote per kilogram and per garment together. Then the reader can see which of the two a proposed change would actually move.
- Write the mass loaded onto the batch card. It is the cheapest thing in this course, and everything else depends on it.