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Association for the Advancement of Medical Instrumentation (AAMI)

"Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities"


Overview: This standard establishes a system of classification for protective apparel and drapes used in health care facilities based on their liquid barrier performance and specifies related labeling requirements and standardized test methods for determining compliance.

Standard Type(s)

An explicit set of requirements to be satisfied by a material, product, system, or service: Examples of specifications include, but are not limited to, requirements for; physical, mechanical, or chemical properties, and safety, quality, or performance criteria. A specification identifies the test methods for determining whether each of the requirements is satisfied.

Personal Protective Equipment
Body Protection

All items of clothing and/or accessories (whether or not detachable) designed and manufactured to provide specific protection. This includes bullet-proof clothing, general protective clothing and full body ensembles that protect from cuts, radiation, temperature extremes, hot splashes from molten metals and other hot liquids, potential impacts from tools, machinery and materials and hazardous chemicals. Examples of body protection include laboratory coats, coveralls, vests, jackets, aprons, surgical gowns and full body suits

  • Medical protective clothing
  • Coveralls
  • Apron
  • Gowns
  • Drapes
  • Biological
SOC Codes
29-0000 Healthcare Practitioners and Technical Occupations
  • 29-1000 Health Diagnosing and Treating Practitioners
    • 29-1063 Physicians, Internal Medicine
    • 29-1069 Physicians and Surgeons, All Other
    • 29-1140 Registered Nurses

Table 3: ANSI/AAMI PB 70:12 classification of barrier performance of surgical gowns, other protective apparel, surgical drapes and drape accessories


Level1 Test Liquid Challenge Result Expected Barrier Effectiveness
1 AATCC 42 Impact Penetration2 Water = 4.5 g Minimal water resistance (some resistance to water spray)
2 AATCC 42 Impact Penetration Water = 1.0 g Low water resistance (resistant to water spray and some resistance to water penetration under constant contact with increasing pressure)
AATCC 127 Hydrostatic Pressure3 Water = 20 cm
3 AATCC 42 Impact Penetration Water = 1.0 g Moderate water resistance (resistant to water spray and some resistance to water penetration under constant contact with increasing pressure)
AATCC 127 Hydrostatic Pressure Water = 50 cm
4 ASTM F1670 Synthetic Blood Penetration Test (for surgical drapes) Surrogate Blood no penetration at 2 psi(13.8 kPa)
Blood and viral penetration resistance (2 psi)
ASTM F1671 Viral Penetration Test (for surgical and isolation gowns) Bacteriophage
no penetration at 2 psi(13.8 kPa)

1 In order of increasing protection

2 American Association of Textile Chemists and Colorists (AATCC) 42 Water resistance: impact penetration test determines the ability of a material to resist water penetration under spray impact [AATCC 2000]

3 AATCC 127 Water resistance: hydrostatic pressure test determines the ability of a material to resist water penetration under constant contact with increasing pressure [AATCC 1998]


Only Level 4 gowns are tested for viral penetration resistance, and therefore only Level 4 garments are considered impermeable to viral penetration using ASTM F1671. The gowns complying with the lower levels (Level 1, 2, and 3) cannot be considered impermeable. However, Level 1–3 gowns can provide increasing resistance to liquids. ANSI/AAMI PB70 Level 1, 2, and 3 surgical/isolation gown-testing requirements only use water as a challenge. Because the surface tension of water is much higher than that of blood, blood can penetrate through fabrics more readily than water. Therefore, no correlation can be made between AATCC water resistance tests (AATCC 42 and AATCC 127) and ASTM F1671 viral penetration tests, and consequently, protection provided by Levels 1, 2, 3 gowns and that of Level 4 gowns. A common misunderstanding among many end-users is that they are protected from blood, body fluids, and other potentially infectious materials (OPIM) when they wear any type of fluid-resistant garment or surgical or isolation gown.

Testing Laboratories
Nelson Laboratories, Inc. - Salt Lake City, UT, 84123

FDA Registered and ANSI-ASQ National Accreditation Board/ACLASS


Phone Number: (801) 290-7500


ISO 17025

Scope of Accreditation

ASTM D5151 - 19 , ASTM D6124 - 06 (Reapproved) , ANSI/AAMI PB70:2012 , ASTM F1342 / F1342M - 05 (Reapproved 2022) , ASTM F1670 / F1670M - 17a , ASTM F1671 / F1671M - 22 , ASTM F1862 / F1862M - 17 , ANSI/AAMI PB70 - Class 3 , ASTM F2100 - 21 , ASTM F2101 - 22 , ASTM F1819 - 19 , ANSI/AAMI PB70 - Class 4


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