ISO 8442-5:2004

Overview

ISO 8442-5:2004 specifies a reproducible laboratory method to assess the sharpness and edge retention of hand knives used in food preparation (professional and domestic). The standard defines a cutting test that simulates repeated cutting actions against a controlled synthetic test medium, producing two key performance indicators: Initial Cutting Performance (ICP) and Cutting Edge Retention (CER).

Keywords: ISO 8442-5:2004, sharpness test, edge retention, cutlery, knives, food contact materials.

Key Topics and Requirements

• Scope: Applies to hand knives for food preparation; excludes powered blade instruments. Both plain-edge and specialized-edge designs are covered.
• Blade types:
  • Type A: User-resharpenable edges or edges with pitch > 1 mm.
  • Type B: Edges not intended to be resharpened on a steel.
• Test principle: Repeated forward and reverse strokes (one cutting cycle = one forward + one reverse stroke) against a pack of synthetic card medium; measure depth cut each cycle and accumulate total card cut (TCC).
• Apparatus & parameters:
  • Nominal test load: 50 N (static at test start).
  • Stroke length: 40 mm (tested length 50 mm = 40 mm stroke + 10 mm card width).
  • Nominal cutting speed: 50 mm/s (verified average ≈ 45 ± 0.5 mm/s).
  • Card pack: strips 10 mm wide, pack depth max 50 mm, clamped with 130 ± 2.5 N.
  • Test medium: chemical soda pulp card containing (5 ± 0.5)% silica (quartz) abrasive; strips conditioned to 55 ± 5% RH at 20 ± 2 °C.
  • Measurement: displacement transducer with resolution ≥ 0.1 mm to record depth per cycle.
• Test duration / cycles:
  • Type A: 60 cycles
  • Type B: 200 cycles
• Performance criteria:
  • Minimum ICP: 50 mm (initial cumulative cut)
  • Minimum CER (TCC): Type A = 150 mm, Type B = 1 500 mm

Applications

• Quality control and incoming inspection by cutlery manufacturers to verify new-knife sharpness and expected wear performance.
• Independent testing laboratories and material testing facilities performing standardized sharpness and durability tests.
• Product specification and compliance documentation for retailers and procurement teams specifying cutlery for foodservice or domestic markets.
• R&D teams comparing blade materials, heat treatments, edge geometries and resharpening behaviors against objective metrics (ICP, CER).
• Regulatory and conformity assessments where a recognized method for knife sharpness and edge retention is required.

Related Standards

• ISO 8442 series (Materials and articles in contact with foodstuffs - Cutlery and table holloware):
  • Part 1: Requirements for cutlery for preparation of food
  • Part 2: Stainless steel and silver‑plated cutlery
  • Part 3: Silver‑plated table and decorative holloware
  • Part 4: Gold plated cutlery
  • Part 6–8: Other plating and precious metal requirements
• Use ISO 8442-5:2004 in conjunction with other ISO 8442 parts when assessing material-specific or plating-related requirements.

For manufacturers and labs seeking reproducible sharpness and wear data, ISO 8442-5:2004 provides a standardized, repeatable test method and defined pass/fail metrics (ICP, CER) for consumer and professional cutlery.