AQL Inspection in Pakistan: Sample Sizes, Accept and Reject Limits

Buyers fix AQL before production, and the lot passes or fails on arithmetic

AQL, the Acceptable Quality Limit, is the worst defect rate a buyer will accept from a random sample of a packed lot. Most buyers write it into the purchase order, where it governs the shipment.

A buyer can't open every carton in a 5,000-piece shipment. An inspector draws a sample against a published statistical table and checks each piece against an agreed defect list. TradeShield's Pakistan inspection guidance states the rule: a shipment fails when defect counts exceed the limit.

For Pakistani exporters the exposure is concentrated by sector. Garments, textiles and leather are repeat-business categories, so a failed inspection damages the next order as much as this one.

Lot size and inspection level set the sample, and a supplier's record moves the level

Sample sizes come from the ISO 2859-1 tables, published in their United States form as ANSI/ASQ Z1.4. Only two inputs drive the table: lot size, and inspection level, where general level II is the default.

Lots below 51 pieces fall in codes A to D and are rare in export programmes. Accept means the lot passes at that count or fewer, and reject means it fails at that count or more. There is no middle band, which is why the sample is drawn at random across cartons, never from a box the factory selects.

The 2,000-piece t-shirt lot falls in code K. A 600-piece lot of woven trousers is code J: 80 pieces are sampled, five or fewer major defects pass, and six fail. Critical defects are handled separately, at AQL C:0. That is zero tolerance, so one critical defect fails the lot regardless of sample size.

Switching rules move the inspection level with production history. Normal inspection moves to reduced after 10 consecutive lots are accepted, and to tightened when 2 of 5 consecutive lots are not accepted. Tightened inspection draws a larger sample and narrows the tolerance. Reduced inspection rewards consistent production with leniency. Tightened is itself discontinued after 5 further non-accepted lots. By then the line has a systemic problem, not a lot problem.

Major defects count against 2.5 and minor defects against 4.0

Major defects affect usability, appearance or safety, and buyers refuse shipments over them: visible stitching faults, shading between pieces in one carton, broken zippers, missing buttons, measurements beyond tolerance. They count against Mj:2.5.

Minor defects are less severe. A reasonable customer wouldn't return a product over a small stain inside a collar that is invisible when worn, a loose thread end or slight seam puckering. These count against Mi:4.0.

If the purchase order doesn't say which defects are major and which are minor, the inspection has nothing to classify against.

Most buyers settle on 2.5 for major and 4.0 for minor, because that combination balances quality against production reality. Premium programmes tighten toward 1.5 for major. Commodity orders loosen further.

The recurring error is to treat AQL as an inspection problem. It is a production problem: AQL measures quality, and it does not create it. YTTWear's guidance for apparel buyers explains why the system works: inspection removes the conflict of interest that arises when the factory pays the inspector.

Fabric is graded separately, with penalty points for each defect's length

ASTM D5430-26, the four-point method, gives each defect penalty points by its length.

Points accumulate across the roll and are expressed per 100 square yards or 100 linear yards. Most apparel programmes work to a threshold near 28 points per 100 square yards. Shade is checked against an approved reference at grade 4 and above on the grey scale. Shade that drifts past that limit counts as a major defect, even where the fabric is structurally sound.

A fabric defect that survives a visual check becomes a garment defect that fails AQL later: a pinhole becomes a hole in the finished shirt. Tetra Inspection's Pakistan findings list colour inconsistencies among the recurring categories. Grosskord's buyer problem list names a related failure: factories change materials after sampling, which only a material-stage check detects.

A failed lot has four remedies, and none of them is free

The lot can go to a full check, in which every piece is examined and defective units are removed. It can be reworked and re-inspected through the same sampling. A buyer can accept it conditionally, at a negotiated markdown per unit. Or it can be rejected outright, which leaves production and freight costs with the exporter.

Inspection costs little next to those alternatives. Published market rates for Pakistan run about $150 to $400 per inspector day (TradeShield), while a rework cycle consumes production days and a second fee.

The last inspection that can still correct a lot happens during production

Prevention is the cheapest option. A during-production inspection at the 30 to 60 percent mark catches defects while they remain fixable, and QIMA publishes the same stage as a checkpoint inside the run. Cotecna's stages require goods to be substantially export-packed before a final check, which leaves the during-production stage as the last one with room to correct a lot.

Each stage catches what the others structurally cannot, so the sequence decides the value. A fabric problem missed before cutting surfaces in the finished garments, when the only remedy is new fabric. SGS publishes the same family of stages, from initial production to final random inspection, and Intertek's inspection hub covers the same sequence.

Inspection demand across Pakistan and Bangladesh rose sharply through 2025 (V-Trust), which is why booking windows stretch in peak season. In those months, book early enough that the finding still arrives while somebody can act on it.

Tti Labs inspects at C:0, Mj:2.5 and Mi:4.0 under ISO/IEC 17020 accreditation

ISO/IEC 17020 accredits inspection bodies, which issue inspection reports, and ISO/IEC 17025 accredits testing laboratories, which issue test reports. Tti Labs inspects through Tti Inspections Pvt Ltd, which holds 17020 accreditation under PNAC certificate IB-006, valid to 12 September 2027 and listed on the PNAC active register.

• Finished goods inspection to these parameters, available standalone or inside the full cycle.

• The published eight-stage cycle: sample picking, pre-production inspection, initial production inspection, during-production inspection, pre-final inspection, pre-shipment inspection, full check and loading supervision.

• Laboratory backup through analytical testing services under ISO/IEC 17025 accreditation (PNAC accreditation LAB-022), where a defect raises a material question.

• Offices in Lahore, Karachi, Faisalabad and Sialkot, with liaison points in Multan and Kasur.

Tti Labs inspects and reports. It does not rework goods, coach lines to pass, or soften findings for the factory.

Book an AQL inspection with Tti Inspections Pvt Ltd. UAN 111 786 001. ISO/IEC 17020 accredited sampling.