What the Four Point System Actually Measures, and What It Misses

The four point system converts visible damage in a roll of fabric into a single comparable number: penalty points per 100 square yards. A defect earns one to four points according to its length, the points are totalled and scaled to a fixed area, and the result is measured against a limit agreed in the contract. It is the most widely used fabric grading method in the garment trade, it is fast, and the mechanics are precise. What it does not do, and what almost nobody realises, is tell you whether the cloth is any good. Here is the whole method, and then the part that surprises people.

What does each defect cost in points?

Length decides the penalty, in either direction of the cloth. A defect up to 3 inches earns 1 point, over 3 and up to 6 inches earns 2, over 6 and up to 9 inches earns 3, and anything longer than 9 inches earns 4. Holes and openings are scored on their own scale: 1 inch or under earns 2 points, larger than 1 inch earns 4. One rule gets missed constantly: a single linear yard can never be penalised more than 4 points, however many faults sit inside it.

How do points become a score you can compare?

You scale the total to a fixed area, because a long roll will always collect more faults than a short one. Multiply total points by 3600, then divide by the fabric width in inches multiplied by the yards inspected. The 3600 is just 36 inches times 100, which puts the answer in points per 100 square yards. Take a 120 yard roll at 46 inches wide carrying 24 points: 24 times 3600 is 86,400, divided by 46 times 120 gives 15.65 points per 100 square yards. That number is the entire output of the exercise.

How is the inspection supposed to be run?

Under conditions specific enough that changing them changes the answer. Illumination should be at least 1075 lux from white fluorescent lamps, directed perpendicular to the cloth. The fabric runs at roughly 45 degrees to the vertical on the inspection frame, and the inspector views it from about a metre away at a speed agreed with the customer rather than whatever the machine will do. Inspection normally covers around 10 percent of the lot, not every roll, so a passing report describes a sample and not your consignment.

What does a four point pass not tell you?

Most of what you would actually argue about later. The system scores size and never classifies type, so a stain, a slub and a broken pick of the same length are identical to it. Shade variation between rolls sits outside it, and so do shrinkage, tensile strength and tear strength. Fabric weight and width are checked separately and form no part of the score, which is why a roll can pass four point inspection cleanly and still be the wrong GSM for your costing. Weigh a disc from a few rolls and check the GSM yourself before the lot goes to cutting. A pass means the cloth is not unusually damaged. It does not mean the cloth is correct.

So what score counts as a pass?

Whatever you wrote in the purchase order, because the standard sets no threshold at all. Four point is one of three point-assignment options inside ASTM D5430. ASTM is the standards body founded in 1898 as the American Society for Testing Materials, renamed the American Society for Testing and Materials in 1961, and known simply as ASTM International since 2001, when the letters stopped standing for anything. D5430 describes itself as a procedure for grading fabric from visual inspection, to be used with requirements "mutually agreed upon by the purchaser and the supplier". The standard goes further and warns that penalty points for the same rolls "may vary considerably" across its three options. So 40 points per 100 square yards for first quality, 28 for cotton twill and denim, 20 for synthetics and export programmes are all commercial conventions, not rules. If the number is not in your contract, you have no basis to reject anything.

Where does the system quietly work against you?

Three places, once you rely on it. The 4 point cap per linear yard means one catastrophic yard scores the same as one mediocre yard, so concentrated damage is understated by design. Scaling to 100 square yards spreads faults evenly across the roll on paper even when they are clustered in a stretch you cannot cut around. And the metric variant is scored per 100 square metres, where the numbers do not transfer: 100 square metres is about 119.6 square yards, so a 40 point limit becomes roughly 48 in metric terms. A specification quoting a smaller number in metric than in imperial is either deliberately stricter or converted backwards, and it is worth asking which.

None of this makes four point a bad tool. It is fast, repeatable and arguable, which is what two parties need when they are looking at the same roll from opposite sides of a contract. It only becomes dangerous when a passing report is read as a guarantee of quality, rather than what it is: a measurement of visible damage, in a sample, against a limit you agreed to.