All medical gowns and drapes are governed by a set of standards and test methods that all manufacturers must know.
What is the ANSI/AAMI PB70 Standard?
AAMI introduced the voluntary standard ANSI/AAMI PB70, Liquid Barrier Performance and Classification of Protective Apparel and Drapes Intended for Use in Health Care Facilities, to see key identification measures for the suitable selection of protective apparel and drapes, like medical isolation gowns, to be used within the healthcare setting.
The standard created a classification system (Levels 1 to Levels 4) for protective clothing and drapes. It was based on liquid barriers performance using standard test methods and associated labeling requirements.
AAMI and ANSI set these standards, most recently in a 2012 update to ANSI/AAMI PB70.
Standard covers all kinds of Protective Apparel and Drapes
They are labeled with liquid barrier or liquid borne microbial barrier claims
Example of protective apparel and surgical drapes:
- isolation gowns
- single-use surgical gowns
- multiple-use surgical gowns
- laboratory attire
- decontamination garments
- sleeve protectors
- other garments
They have been classified as medical devices by FDA (the U.S. Food and Drug Administration) under 21 CFR 878.
Surgical protective apparel is classed by the FDA under 21 CFR 878.4040
Surgical drapes are classified under 21 CFR 878.4370.
5 Requirements of ANSI/AAMI PB70:2012
- Labeling requirements
– Device labeling
– Package labeling
- Technical information
- Barrier performance classification
- Test method
Protective clothing such as surgical gowns, surgical drapes, and drape accessories should be identified with their class of barrier performance. These critical zones are determined using seams and attachment points.
The number of product classification labels denoting performance of critical zones components having the lowest barriers performance.
The multiple-use products have to be marked with their lifespan (according to the manufacturer’s instructions).
Additional labeling requirements exist beyond that per in the standard.
e.g., FDA labeling requirements applicable to any or all medical devices.
The manufacturer should provide technical information upon request that included the following:
- Detailed information on the barrier performance of every key area component and also the critical zone.
- To ensure the product continued safety and effectiveness, the instructions for multiple-use products will include the number of uses that can be made.
Tell the users that the product’s labeled barrier performance is not verified or that it has passed the labeled usage period. It is better to downgrade the product to a non-protective category than a lower barrier performance.
Barrier Performance Classification
Samples of the critical zones for surgical gowns, isolation gowns, drape accessories, and surgical drapes must be taken and tested.
The classification levels of barrier performance as defined below within the Test method table.
Level 1 Gowns and Drapes
Tested for water resistance by AATCC 42 (impact penetration) and under the conditions. All critical zones should have a blotter weight gain of not quite 4.5 g, with an AQL of 4 %/RQL of 20 %.
Level 2 Gowns and Drapes
Tested for water resistance by AATCC 42 (impact penetration) and AATCC 127 (hydrostatic pressure) and under the conditions. All critical zones must have a blotter weight gain not exceeding 1.0 g, a hydrostatic resistance of a minimum of 20 cm, and an AQL of 4/RQL 20 %.
Level 3 Gowns and Drapes
Tested for water resistance by AATCC 42 (impact penetration) and AATCC 127 (hydrostatic pressure) and under the conditions. All critical zone tests are identical to Level 2, except that the hydrostatic resistance is a minimum of 50 cm.
Level 4 Gowns
When an isolation gown, surgical gown, or other protective clothing is tested for resistance to bacteriophage Phi-X174 by ASTM F1671 and under the conditions. All critical zones should have passing results and an AQL of 4 %/RQL 20 %.
Level 4 Drapes
A surgical drape or drape accessories must be tested for synthetic blood resistance by using ASTM F1670. All critical zone components must pass with an AQL below 4 %.
Based on the results of these standardized tests, we will see a table below of summarizes the requirements of ANSI/AAMI PB70:2012.
ANSI/AAMI PB70 Barrier Performance
Anticipated Barrier Effectiveness
|AAMI Level 1||AATCC 42 Impact Penetration||Water||Water impact
< 4.5 g
|Minimal water resistance (some resistance to water spray)|
|AAMI Level 2||AATCC 42 Impact Penetration||Water||Spray impact
< 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 Pressure||Hydrostatic Pressure
> 20 cm
|AAMI Level 3||AATCC 42 Impact Penetration||Water||Spray impact
< 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||Hydrostatic Pressure
> 50 cm
|AAMI Level 4||ASTM F1670 Synthetic Blood Penetration Test (for surgical drapes)||
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)||
no penetration at 2 psi(13.8 kPa)
The critical zone of a surgical gown or other protective clothing (expect the isolation gowns). All of them require the front area of the gown from chest to knees and also the sleeves from the cuff to above the elbow.
The front of the gown and therefore the areas of the sleeves of the critical zone should have a barrier performance of a minimum of Level 1.
If the rear panel of the gown is nonprotective, the gown needs to be labeled.
Protective areas and seams must have at minimum of the identical barrier performance because of the lower-performing area. There are not any requirements for barrier-free seams between non-protected and protected areas.
Isolation gowns or other gowns use in isolation applications, the critical zone has gone to comprise the whole gown, including the seams but excluding the cuffs, hems, and bindings, and shall have a barrier performance of a minimum of Level 1.
Surgical drapes and drape accessories
The entire surgical drape must have at least Level 1. Between seams, protected areas, and also the remainder of the garment, it should have the lowest-performing area of barrier protection.
The manufacturer has to provide the precise dimensions of the critical zones and detailed information on the barrier performance of every critical zone component.
*Follow the link below to know more about the critical zones of the isolation gown.
Surgical Gown vs Isolation Gown – What Are the Differences? 3 types of Isolation Gowns You Should Know!
Definition of AATCC and ASTM
What is AATCC?
AATCC is called The American Association of Textile Chemists and Colorists. The world’s largest non-profit association serving textile professionals. They offer educational development, test method development, quality control material, networking, and support for apparel and textile professionals around the globe.
AATCC 42 is also known as the Water Resistance: Impact Penetration Test.
It shows how resistant the fabric is to strikethrough from fluids spray and splash onto it.
AATCC 127 is named the Water Resistance Hydrostatic Pressure Test.
This shows how resistant the fabric is to be struck through by water pressure.
What is ASTM?
The American Society for Testing and Materials also referred to as ASTM international. It is one of the largest international standard-setting organizations in the world.
ASTM International brings together users, producers, and consumers from around the world to create voluntary consensus standards. The standards are developed under a process that embraces the World Trade Organization Technical Barriers to Trade Agreement principles. The ASTM standard development process is transparent and opens to everyone. This allows governments and individuals to take part directly and as equals in the global consensus decision.
These standards are internationally accepted and used. They cover metals, paints, plastics, textiles, petroleum and medical devices.
ASTM F1671, a standard for Resistance of Materials in Protective Clothing to Permeation by Blood-Borne Pathogens Test. When you want the protective clothing is AAMI Level 4, it must pass through this requirement test.
The test method has been specifically designed for penetration of HBV, HCV, and HIV. These organisms are difficult to test, the test uses a bacteriophage, Phi-X174.
Phi-X174 is one of the smallest known viruses, and it is similar in size and shape to HCV, the tiniest bloodborne viral pathogen.
The material of the gown is placed in a nutrient broth containing PhiX174 for the time and pressure test:
- 5 mins – at air pressure
- 1 min -at two PSI (pounds per square inch)
- 54 mins – at air pressure
If visible liquid penetration occurs before the end of 60 minutes, the test is terminated.
If there is no liquid penetration, a sensitive microbiological assay is done to confirm or fail. Any evidence of viral penetration for a test specimen constitutes a failure.
According to the barrier performance classification specified by ANSI/AAMI PB70, manufacturers must manufacture the products by the regulations.
This specification stipulates the design standards, critical zones, physical performance standards, labeling, and document requirements that surgical gowns and surgical drapes must-have. It doesn’t matter how the product is named (i.e., protection gown, isolation gown, or surgical gown), it is also important to look for the required AAMI level when choosing the gowns.
- AAMI levels determined per ANSI/AAMI PB70:2012 Liquid barrier performance and classification of protective apparel and drape intended for use in health care facilities
- PPE-Info – Standard Details. (2015, November 20). CDC.
- AAMI level standards for gowns. (2019, December 20). Mun Global.
- Medical gown. (2021, January 13). U.S. FOOD & DRUG ADMINISTRATION.
- American Association of Textile Chemists and Color. (n.d.). Testing – AATCC – Use standard test methods for meaningful evaluation. AATCC.
- 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. (n.d.). ASTM.