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Penetration Testing

 

The European Standard EN 13795 for Surgical drapes, gowns and clean air suits recognises that a key performance requirement of surgical textiles is to provide protection for the patient from microbial contamination that may be present in the theatre setting. The standard stipulates bacterial barrier properties when the textiles are challenged in a wet and dry state.

 

Wet Bacterial Penetration Testing - EN ISO 22610

This test determines the resistance of a material to the penetration of bacteria carried by a liquid through a material by the combined effect of friction, pressure and wetting. The pressure is intended to mimic the type of pressure exerted by a surgeon's elbow during a procedure and was developed specifically to measure the penetration by bacteria through operation materials of reusable or single-use material.

In this test, the Rulla moving finger apparatus is used to apply a constant tensile force on an inoculated donor material which is positioned on top of the test material. The assembly of materials is placed on an agar plate, secured with steel rings and the finger placed on top of the materials with a specified force to bring the test specimen into contact with the agar surface.

The finger is moved over the entire surface of the plate for 15 minutes, after which time the agar plate is replaced with a fresh one and the test repeated until five consecutive tests are performed.

The agar plates are incubated and the total number of colonies on the surface of the plate are counted. The estimated bacterial challenge (T) is calculated and compliance with the performance requirements determined.

Dry Bacterial Penetration Testing - EN ISO 22612 This test is designed to simulate the penetration of bacteria-carrying skin scales through fabrics and provides a means for assessing the resistance to penetration through barrier materials of bacteria-carrying particles.

In this test, a portion of talc contaminated with a known number of Bacillus subtilis spores are poured onto the test piece inside a container. A container without the contaminated talc is used as the control. An agar plate is inserted into the base of the container below the test piece. The platform supporting the container is vibrated for 30 minutes by a pneumatic ball vibrator. Any talc that has penetrated through the test piece will be captured by the agar plate. The agar plate is then incubated and the total number of colonies on the surface the plates are counted. The mean bacterial count is calculated and compliance with the performance requirements determined.

If you have a product you wish to have tested or have any questions, please contact smtl.info@wales.nhs.uk

 

Relevant Standards

  • BS EN 13795-1 Surgical clothing and drapes. Requirements and test methods - Surgical drapes and gowns EN 13795
  • BS EN 13795-2 Surgical clothing and drapes. Requirements and test methods - Clean air suits
  • ISO 22610 Surgical drapes, gowns and clean air suits, used as medical devices, for patients, clinical staff and equipment. Test method to determine the resistance to wet bacterial penetration
  • BS EN ISO 22612 Clothing for protection against infectious agents. Test method for resistance to dry microbial penetration