Overview
ISO 17551:2018 - Leather - Pickled sheep pelts - Guidelines for grading on the basis of defect and size provides standardized guidance for grading pickled sheep pelts by defect and size. The standard defines grading criteria, defect classifications and area-based size categories for lots of pickled sheep pelts, and requires that pH be checked (recommended pH 2.0 ± 0.2) before grading. ISO 17551:2018 is intended to support consistent quality assessment, sorting and commercial specification of pickled sheep pelts.
Key topics and requirements
- pH requirement: Verify pickled sheep pelt pH of 2.0 ± 0.2 prior to grading.
- Grading by defects (Grades I–V):
- Grade I: defects ≤ 10% of total area; generally free from score marks, warble holes, meat/fat, pox marks, cockles; fleshy with fine grain. Thinner skins otherwise meeting Grade I are treated as Grade II.
- Grade II: defects 11–20% of total area; neck and shoulder free from defects.
- Grade III: defects 21–40% of total area; at least 75% of neck and shoulder free from damage.
- Grade IV: defects 41–70% of total area.
- Grade V: defects > 70% of total area.
- Defect classification system: Defects are assessed by location, concentration, depth and surface area. The standard provides tabular and coded representations (table codes 0–4) describing location (periphery, legs/tail/cheeks, shoulders/central part), concentration (none → high), depth (superficial → thorough) and affected surface (grain or flesh).
- Grading by size (area of 12 pelts):
- Extra large: > 108 ft² (≈ 10 m²)
- Large: 85–108 ft² (≈ 7.9–10 m²)
- Medium: 61–84 ft² (≈ 5.7–7.8 m²)
- Small: 37–60 ft² (≈ 3.4–5.6 m²)
- Extra small:
