Every visible defect on the face of the fabric is assigned penalty points according to its longest dimension. The points are then normalised against the area actually inspected, so a short roll and a long roll can be judged on the same scale.
The 3600 constant comes from the unit conversion: fabric area in square yards is length in yards × width in inches ÷ 36, and the result is scaled by 100 to express it per hundred square yards.
| Defect length | Metric | Penalty points |
|---|---|---|
| Up to 3 inches | Up to 7.5 cm | 1 point |
| Over 3 up to 6 inches | 7.5–15 cm | 2 points |
| Over 6 up to 9 inches | 15–23 cm | 3 points |
| Over 9 inches | Over 23 cm | 4 points |
Two rules people forget. First, a single defect can never score more than 4 points regardless of length. Second, most buyers apply a separate cap of 4 points on any one linear yard — so a roll can pass the overall average and still be rejected for one concentrated bad patch.
These conditions are the quiet admission at the centre of the standard: reliable manual inspection requires the fabric to be slowed down, lit up and stared at. That is why 4-Point inspection is almost always a sampling exercise — typically 10% of production — rather than total coverage.
The 4-Point System (ASTM D5430) is the most widely used fabric inspection standard in the garment industry. Inspectors assign penalty points to each visible defect based on its length — 1, 2, 3 or 4 points — then normalise the total to points per 100 square yards so rolls of different sizes can be compared fairly.
Defects up to 3 inches score 1 point. Over 3 up to 6 inches scores 2 points. Over 6 up to 9 inches scores 3 points. Over 9 inches scores 4 points. No single defect can ever score more than 4 points, no matter how long it is.
There is no universal figure — each buyer sets their own limit. In practice 20 points per 100 square yards is the most common threshold for apparel fabric, with some buyers accepting up to 28 and premium programmes demanding 15 or lower. Always confirm the limit written into your specific buyer contract.
Yes. ASTM D5430 covers both woven and knitted fabric. For knits, the defects being scored are typically holes, drop stitches, barré, lycra or elastane breaks, oil lines and needle lines — the same faults defined in ASTM D3990.
The standard specifies inspection at a speed no greater than 15 yards per minute, under lighting of at least 80 foot-candles, with the fabric viewed at roughly 3 feet. Only defects visible under those conditions on the face of the fabric are scored.
Yes. Beyond the overall points per 100 square yards limit, most buyers also apply a rule that no single linear yard may accumulate more than 4 points. A roll can pass on average and still be rejected on this clause.
ASTM D5430 requires inspection at no more than 15 yards per minute under 80 foot-candle lighting — because a human eye needs the fabric slowed down and lit up. Knit-I inspects on the machine, at production speed, and halts it the moment a defect appears. The roll never reaches the inspection table with the defect still in it.
See Knit-I on your machines →The full 4-Point System reference: scoring, conditions, acceptance limits and how it is applied to knits.
ReferenceEvery defect named in ASTM D3990 — with causes and remedies for each.
CalculatorTranslate your points score into what escaped defects actually cost per year.