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Microbial Resistance Testing

Evaluate your products’ ability to resist mold growth in elevated moisture conditions

Microbial testing in a laboratory.


Mold spores are ubiquitous and can grow and thrive in high-moisture conditions. The resulting mold growth can cause staining, decay, degradation or foul smell on any number of products commonly found in buildings, including drywall, flooring, paints and insulation. In addition, microbial volatile organic compounds (MVOCs), chemicals associated with microbial metabolism, can negatively impact human health.

Conducted according to ASTM standards, microbial resistance testing assesses a products’ ability to resist mold growth, providing manufacturers with the information they need to help ensure their products perform well in possible high-moisture conditions.


Microbial resistance testing helps manufacturers understand the impact of high-moisture conditions on their products and guides them toward the development of products that resist mold growth and support better indoor air quality. By conducting microbial resistance testing, manufacturers of all kinds of building materials, construction products, furniture, textiles, insulation, and paints and coatings can better understand the impact of mold growth on their products, providing customers with care instructions or engineering products that are increasingly resistant to mold growth.

Why UL Solutions

Our dedication to science and objectiveness positions us to be a trusted resource for manufacturers of all kinds of building materials to understand the need for independent testing. We can help you build trust with your customers and consumers.

Related standards

  • ASTM G21 Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi
  • ASTM D3273 Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber
  • ASTM D6329 Standard Guide for Developing Methodology for Evaluating the Ability of Indoor Materials to Support Microbial Growth Using Static Environmental Chambers
  • ASTM C1338–00 Standard Test Method for Determining Fungal Resistance of Insulation Materials and Facings