PPE Best Practice

AAMI Level Standards for Gowns

The Association for the Advancement of Medical Instrumentation (AAMI) standards are designed to help medical-device companies meet global standards for the safe use of medical devices. AAMI introduced the voluntary standard ANSI/AAMI PB70:2012, Liquid Barrier Performance and Classification of Protective Apparel and Drapes Intended for Use in Health Care Facilities, to determine key identification measures for the appropriate selection of protective apparel and drapes, such as medical gowns, for use in healthcare facilities (Pfiedler Enterprises, 2016). The AAMI gown classification stems from four levels of barrier performance, measured accordingly with the following standardised tests:

  • AATCC 42-2017: Measures resistance of fabrics to the penetration of water by impact (AATCC, 2018)
  • AATCC 127-2017: Measures resistance of fabric to the penetration of water under hydrostatic pressure (AATCC, 2017)
  • ASTM F1670-17: Evaluate resistance of materials used in protective clothing to penetration by synthetic blood under conditions of continuous liquid contact (ASTM, 2017)
  • ASTM F1671-13: Measure penetration by blood-borne pathogens using a surrogate microbe under conditions of continuous liquid contact (ASTM, 2013)
BARRIER PERFORMANCEBARRIER PROTECTIONRESISTANCE MEASURESTESTTEST CRITERIAACCEPTABLE QUALITY LEVEL
Level 1MinimalLiquid PenetrationAATCC42Water Impact ≤ 4.5g4%
Level 2LowLiquid PenetrationAATCC42

AATCC127		Spray Impact ≤ 1.0g

Hydrostatic Pressure ≥ 20cm		4%

4%
Level 3ModerateLiquid PenetrationAATCC42

AATCC127		Spray Impact ≤ 1.0g

Hydrostatic Pressure ≥ 50cm		4%

4%
Level 4HighLiquid and Viral PenetrationASTM F1671Pass4%

AAMI Levels

Defining the best level of protection for the standard ANSI/AAMI PB70:2012 involves an understanding of the critical zones of a gown and what each level of barrier performance entails, so that the best gown is chosen for use by healthcare workers.

The critical zones of gowns comprise of the front of the gown and the sleeves, which are both primary areas with the greatest risk of exposure to fluids and blood-borne pathogens. As the level increases, so does the need for greater barrier protection for the entire critical zone.

  • Level 1: Minimal level of fluid barrier protection
  • Level 2: Low level of fluid barrier protection
  • Level 3: Moderate level of fluid barrier protection
  • Level 4: Highest level of fluid and viral barrier protection

References

  1. Pfiedler Enterprises 2016, AAMI Levels and Surgical Gowns: Know if You’re Protected, viewed 17 July 2018, <http://www.pfiedler.com/ce/1191/files/assets/common/downloads/AAMI%20Levels%20and%20Surgical%20Gowns.pdf>
  2. AATCC TM42-2017, Water Resistance: Impact Penetration Test, American Association of Textile Chemists and Colorists, RTP, NC, USA, 2018, <https://www.aatcc.org/>
  3. AATCC TM127-2017, Water Resistance: Hydrostatic Pressure Test, American Association of Textile Chemists and Colorists, RTP, NC, USA, 2017, <https://www.aatcc.org/>
  4. ASTM F1670 / F1670M-17a, Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Synthetic Blood, ASTM International, West Conshohocken, PA, 2017, <https://www.astm.org>
  5. ASTM F1671 / F1671M-13, Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne Pathogens Using Phi-X174 Bacteriophage Penetration as a Test System, ASTM International, West Conshohocken, PA, 2013, <https://www.astm.org>

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