ISO 11140-3:2007

Overview

ISO 11140-3:2007 - "Sterilization of health care products - Chemical indicators - Part 3" - specifies performance, format, packaging and quality requirements for Class 2 chemical indicators used in the Bowie and Dick‑type steam penetration test for steam sterilizers processing wrapped goods and porous loads. These indicators are intended for use with the standard test pack described in EN 285. ISO 11140-3:2007 defines how the indicator itself must perform and be presented; it does not assess the performance of the test pack or guarantee achievement of sterilization conditions.

Key Topics and Requirements

• Indicator class and purpose: Class 2 chemical indicators per ISO 11140-1, designed to detect steam penetration in Bowie and Dick‑type tests.
• Format and materials
  • Indicator reagent must cover ≥ 30% of substrate surface; spacing between reagent areas ≤ 20 mm.
  • Substrate air porosity ≥ 1.7 µm/(Pa·s) when tested to ISO 5636-3 at 1.47 kPa.
  • Substrate size: A4 (ISO 5457).
  • Uniform substrate colour and writable with permanent ink before and after processing.
  • Reflectance density difference (substrate vs changed/unchanged indicator) ≥ 0.3 (Annex B).
• Performance
  • Uniform colour change after exposure to dry saturated steam at 134 °C for 3.5 min ± 5 s or 121 °C for 15 min ± 5 s (Annex C).
  • Non‑uniform colour change when placed centrally in a standard test pack under defined adverse conditions (sensitivity to air presence - Annex I).
  • No discernible change after dry heat at 140 ± 2 °C for ≥ 30 min (Annex D).
  • No visible transfer of reagent to test load material (Annex F).
  • Compliance through specified test methods and ageing/shelf‑life evaluations (Annexes E, G).
• Labelling & packaging
  • Each indicator must be marked with operating temperature(s), unique batch code, and user‑fillable fields (department, machine no., cycle no., operator, date, result, supervisor).
  • Packaging must protect against moisture, dust and sunlight for stated shelf life.

Applications and Users

Who uses ISO 11140-3:2007:

• Sterilizer manufacturers and OEMs (to validate indicator compatibility with sterilizers)
• Chemical indicator manufacturers (design, testing and labeling)
• Hospital sterile services departments / CSSD (routine Bowie and Dick testing)
• Test laboratories and regulatory bodies (conformity testing and audits)
• Quality managers and biomedical engineers responsible for sterilization validation and routine monitoring

Practical uses:

• Selecting or validating chemical indicators for steam penetration tests
• Designing indicator products that meet EN 285/ISO test requirements
• Establishing routine sterilizer performance checks (Bowie and Dick‑type tests) and documentation practices

Related Standards

• ISO 11140-1 (General requirements for chemical indicators)
• EN 285 (Standard test pack and large steam sterilizers)
• ISO 17665-1 (Sterilization of health care products - Moist heat - Part 1: Requirements for process)
• Other parts of ISO 11140 (Part 4 and Part 5 address alternative Class 2 indicators and air removal tests)

Keywords: ISO 11140-3:2007, Bowie and Dick test, steam penetration test, Class 2 chemical indicators, steam sterilizers, EN 285, sterilization of health care products, indicator performance.