Barrier Properties Of Protective Clothing

When identifying hazards and exposure risks, selecting appropriate gowns and coveralls should be based on the latest scientific insights regarding how protective clothing materials defend against microorganisms found in blood and body fluids. The transmission of microorganisms through protective fabrics is influenced by several factors:

Fabric properties: These include thickness, pore size, and repellency.

Microorganism characteristics: This includes their shape, size, morphology, motility, and environmental adaptability.

Carrier properties: Factors like surface tension, volume, and viscosity are important.

External conditions: Physical, chemical, and thermal stresses affect microorganism movement.

Healthcare environments harbor various microorganisms, such as bacteria, viruses, and some fungi, each varying in size and shape, which impacts their movement through fabric structures. Generally, fungi are larger than bacteria, and bacteria are larger than viruses. For instance, the HIV virus is round and measures 100–120 nanometers in diameter, while the Ebola virus, an RNA virus, has a filamentous shape, typically measuring 974 to 1,086 nanometers in length and about 80 nanometers in diameter.

Microorganisms can be transported by carriers like body fluids, skin cells, lint, dust, and respiratory droplets. A significant number of microorganisms can be present in a minuscule volume of blood or body fluids, often not visible to the naked eye. For example, a 0.1-microliter droplet of blood can contain around 10,000 infectious units of Hepatitis B, making it highly contagious and easily spread. In the case of Ebola, the virus's RNA levels in the blood rise rapidly during the acute phase. One study found an average peak titer of 3.4 x 10^5 RNA copies per 0.1 microliter, much higher than that of Hepatitis B. Studies also show that when liquid containing microorganisms penetrates protective materials, the microorganisms move with the liquid, even if it isn't visible. Thus, standardized tests must be sufficiently sensitive to detect microorganism penetration to ensure protection, especially in garment seams.