AQL: The Statistical Foundation of Rug Inspection
AQL (Acceptable Quality Level) is defined in ISO 2859-1 (equivalent to ANSI/ASQC Z1.4) and provides a statistically valid method for sampling a production lot without inspecting every unit. It answers two questions: how many pieces to inspect, and how many defects are acceptable before the lot is rejected.
How AQL Works in Practice
Two inputs determine the inspection sample size: the lot size (total pieces in the shipment) and the inspection level (General Level I, II, or III — Level II is standard for most consumer goods). A lookup table then gives the sample size code, which maps to the actual number of pieces to inspect.
| Lot Size (pieces) | Sample Size (GIL II) | Major defects allowed (AQL 2.5) | Minor defects allowed (AQL 4.0) |
|---|---|---|---|
| 51–90 | 13 pieces | 0 (reject at 1) | 1 (reject at 2) |
| 91–150 | 20 pieces | 1 (reject at 2) | 1 (reject at 2) |
| 151–280 | 32 pieces | 2 (reject at 3) | 3 (reject at 4) |
| 281–500 | 50 pieces | 3 (reject at 4) | 5 (reject at 6) |
| 501–1,200 | 80 pieces | 5 (reject at 6) | 7 (reject at 8) |
| 1,201–3,200 | 125 pieces | 7 (reject at 8) | 10 (reject at 11) |
Critical defects always have AQL 0 — zero tolerance regardless of lot size. A single critical defect found during inspection is grounds for lot rejection. There is no acceptable critical defect rate in consumer textile products.
Defect Classification for Rugs
Critical — AQL 0
Backing delamination (slip hazard) · Latex compound with restricted substances (REACH/Prop 65) · Pile height deviation creating trip hazard · Sharp foreign object embedded in pile · Flammability failure (if fire-tested specification)
Major — AQL 2.5
Colour deviation ΔE > 2.0 vs. approved standard · Dimension deviation > ±2% or ±1cm · Pattern misregistration > 5mm · Severe shedding (rubbing test failure) · Significant pile height inconsistency (> ±3mm) · Wrong backing system vs. PO spec · Contamination stain > 10mm
Minor — AQL 4.0
Colour deviation ΔE 1.0–2.0 · Dimension deviation ±1–2% · Edge hemming irregularity < 5mm · Loose thread (< 30mm) · Surface fuzz that vacuums clean · Minor packaging label misalignment
The 12-Point Pre-Shipment Inspection Checklist
This is the quality protocol applied by Hileewoo's QC team before every production lot is approved for packaging and export:
Dimension Verification
Measure length and width of each sampled unit in both warp and weft directions. Tolerance: ±2% or ±1cm. Record actual measurements against PO specification.
Pile Height Measurement
Measure pile height at 5 locations across the rug (4 corners + centre). For jacquard constructions, measure both high-pile and low-pile zones. Tolerance: ±2mm from specification.
Colour Evaluation
Compare each colour zone against the approved dye-lot swatch under D65 standard illuminant. Record ΔE reading (spectrophotometer preferred; visual assessment under calibrated lighting acceptable for standard tolerance). Target ΔE < 0.5 internally; reject at ΔE > 2.0.
Pattern Registration Check
For jacquard constructions: measure pattern repeat alignment in both directions. Maximum acceptable misregistration: 3mm over a 50cm repeat. Compare pattern against approved design file.
Rubbing / Shedding Test
Apply 20 firm strokes with a clean white cotton cloth on the pile surface. Evaluate fibre transfer — minimal transfer required. Heavy transfer (visible coating of fibre on cloth) = major defect.
Tuft Pull Test
Grip individual tufts close to the backing and apply ~2–3 kg vertical pull force. Test 10 tufts across the sample. Maximum 1 in 10 may release. Full tuft release = major defect; 2+ in 10 = lot rejection.
Backing Inspection
Examine entire backing surface for: delamination bubbles or peeling, uneven latex coverage (bare canvas spots), latex bleed through to pile face, and correct backing type against PO specification.
Edge and Hemming Quality
Inspect all four edges for: consistent hem width (±3mm), secure stitching without skipped stitches, no fraying or exposed warp threads, and correct hem colour vs. pile face.
Surface Contamination Check
Inspect pile surface under raking light for: oil or grease marks, foreign fibre contamination, staining, and processing chemical residue. Any stain > 10mm = major defect.
Face Weight Spot Check
Cut 10×10cm sample from selvedge area and weigh. Calculate g/m² (multiply by 100). Compare against PO specification. Tolerance: ±8%. Below specification = major defect; below −15% = critical defect.
Packaging and Labelling
Verify: correct polybag size and thickness, accurate hang tag (fibre content, country of origin, care instructions), barcode scan confirmation if applicable, and label language compliance for destination market.
Carton and Shipping Mark
Inspect outer carton: correct dimensions, adequate flute strength (minimum BC flute for rugs), accurate shipping marks (PO number, destination, gross/net weight, piece count), and no moisture damage or compression deformation.
When and How to Use Third-Party Inspection
When Third-Party Inspection Is Worth the Cost
- First order from any supplier — regardless of order value. The inspection cost (USD 200–400) is trivial against the risk of a defective inaugural shipment.
- Orders above USD 15,000 FOB — at this value, the inspection cost represents under 2% of the order and provides documented evidence for any customs or insurance claim.
- Compliance-sensitive markets — EU REACH, US Prop 65, hotel fire test certification. The inspector verifies compliance documentation authenticity.
- New construction or specification — any order where the supplier has not previously produced an approved sample in the exact specification.
Choosing an Inspection Company
| Company | Strength | Best For |
|---|---|---|
| SGS | Largest global network; strong China presence | General pre-shipment inspection; lab testing |
| Bureau Veritas | Strong EU compliance expertise | REACH, EN ISO fire test certification |
| Intertek | Strong US market knowledge (Prop 65, CPSC) | US compliance testing; ASTM standards |
| QIMA | Online booking; fast turnaround; competitive pricing | High-frequency small-order inspections |
| Asia Quality Focus | China-focused; textile specialist inspectors | Technical textile inspection |
Booking protocol: Book your inspection when 80–100% of production is complete — not when 100% is packed. Inspecting before final packaging allows defective units to be pulled and reworked before they are sealed in cartons. Notify your supplier of the inspection date only 24–48 hours in advance to reduce the opportunity for selective presentation of good units.
What to Include in Your Inspection Brief
Provide the inspection company with: a copy of the purchase order with full specifications, the approved pre-production sample (or photos with measurements), the approved dye-lot colour swatch, the AQL levels for critical/major/minor defects, and the specific checks required (from the 12-point checklist above). An inspector without a detailed brief will conduct a generic textile inspection that may miss rug-specific defects.
Handling a Failed Inspection
When an inspection fails (defect rate exceeds AQL acceptance number), you have four options:
- 100% sorting: Supplier 100% inspects and replaces all defective units before re-inspection. Adds 3–10 days. Supplier bears cost if defects are their fault.
- Rework and re-inspect: Supplier reworks specific defects (re-hemming, spot cleaning, pile correction) and inspection is conducted again on the same lot. Faster if defects are isolated.
- Accept with deduction: If defect rate is marginally above AQL and defects are minor, negotiate a price reduction proportional to the defect rate and accept the shipment. Document the agreement in writing.
- Reject and cancel: If defects are critical, pervasive, or indicate systemic production failure, reject the lot. Your purchase order should specify that FOB terms pass risk of loss only upon loading — rejection before loading keeps liability with the supplier.
Frequently Asked Questions
Factory QC Applied Before Every Shipment
Hileewoo applies this 12-point inspection protocol internally on every production lot before packaging. We welcome third-party inspection by SGS, Bureau Veritas, Intertek, or your nominated agency — with 24-hour booking notice.
Discuss Your Quality RequirementsRelated: Why Rugs Shed · Compliance Guide · FOB Pricing Guide · Custom Rug Orders