Table 4. Comparison of barrier performance of surgical and isolation gowns according to ANSI/AMMI PB70 and EN 13795 standards [59,89].

	ANSI/AAMI PB70		EN 13795
	Classification	Testing	Classification	Testing
Low risk	Level 1 Minimal water resistance: some resistance to water spray	AATCC 42 - Water penetration ≤4.5 g	Low performance	EN 20811 - Hydrostatic pressure ≥10 cm (less critical areas) & ≥100 cm (critical areas)
	Level 2 Low water resistance: resistant to water spray and some resistance to water penetration under constant contact with increasing pressure	AATCC 42 - Water penetration ≤1.0 g		EN ISO 22612 - EN ISO 22612 - Resistance to microbial penetration, dry ≤300 (less critical areas)
		AATCC 127 - Hydrostatic pressure ≥20 cm water column		EN ISO 22612 Resistance to microbial penetration, wet ≥2.8 IB (critical areas)
High risk	Level 3 Moderate water resistance: resistant to water spray and some resistance to water penetration under constant contact with increasing pressure	AATCC 42 - Water penetration ≤1.0 g	High performance	EN 20811 - Hydrostatic pressure ≥10 cm (less critical areas) & ≥100 cm (critical areas)
		AATCC 127 - Hydrostatic pressure ≥50 cm water column		EN ISO 22612 - Resistance to microbial penetration, dry ≤300 (less critical areas)
	Level 4 Blood and viral penetration resistance	ASTM F1670 (Blood) & ASTM F1671 (Viral): No penetration at 13.8 kPa		EN ISO 22612 Resistance to microbial penetration, wet ≥6.0 IB (critical areas)

ANSI, American National Standards Institute; AAMI, Association for the Advancement of Medical Instrumentation; AATCC, American Association of Textile Chemists and Colorists; ISO, International Organization for Standardization; ASTM, American Society for Testing and Materials.

AATCC 42 Water resistance: impact penetration test determines the ability of a material to resist water penetration under spray impact; AATCC 127 Water resistance: hydrostatic pressure test determines the ability of a material to resist water penetration under constant contact with increasing pressure; ASTM F1670 Synthetic blood penetration tests determine the ability of a material to resist the penetration of synthetic blood under constant contact; ASTM F1671 Viral penetration tests determine the ability of a material to resist the penetration of a microorganism under constant contact. EN 20811 evaluates a fabric's resistance to water penetration under constantly increasing hydrostatic pressure. The EN ISO 22612 test evaluates a dry fabric's ability to resist penetration of particles carrying microorganisms. The EN ISO 22610 test evaluates a fabric's resistance to microbial penetration under conditions of liquid pooling on the fabric and mechanical rubbing. Test results are expressed in I “Barrier Index.” I=6.0 indicates no penetration.