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Metal / Corrosion - Extraneous and Film Rust

Type of Surface Change

  • Individual, irregularly dispersed rust particles.
  • Brown, mostly locally limited corrosion deposits/rust formation.
  • Given large-surface contact with very rusty products, consequential damage in the form of "instrument impressions" may occur.

Origin & Causes        

  • Rust particles carried over from the pipework.
  • Use of water containing iron or rust, or use of steam containing rust particles.
  • Corrosion products (= rust) that adhere to non-corrosion-resistant disposable products (such as scalpel blades) may come off during the sterilization process, for example, attaching to other instruments.
  • Continued use and reprocessing of non-corrosion-resistant steels (often "old instruments") whose protective layer has been damaged or come off.

Treatment Recommendations        

  • Given a slight and only superficial attack, removal of the deposits through acid-based cleaner may be an option (only for stainless steels), but check afterwards whether the instrument surface is still intact.
  • Provided the damage is still superficial, the instrument may possibly also be treated mechanically (reworked) by the manufacturer or a qualified repair service provider.

Preventive Measures        

  • Disposable items made of steel must not be reprocessed (i.e. treated for reuse).
  • Discard, or treat separately, any non-stainless instruments and materials.
  • Avoid using cheap products (e.g. accessories offered by construction markets, etc.).
  • Carry out effective construction measures to prevent pipework rust particles from entering the cleaning and sterilization stages (e.g. by filtering the feed water mechanically before it enters the washer or sterilizer).

Risk Assessment        

  • A single rusty instrument may be enough to cause consequential corrosive damage in all of the instruments contained in the tray.
  • If rust particles are carried over from the pipework, this may also affect the instruments processed and thus reduce their value.