In the mold-remediation industry, the most acceptable protocols used to determine mold-resistant coatings performance are the ASTM G-21 and ASTM D- 3273/3274 standards, historically referenced by the coatings industry to demonstrate resistance of polymeric films to mold growth on building materials.
Though different in their protocols, both tests are graded on a rating scale based on performance — designed to provide a greater understanding of the test methods referenced by mold-resistant coatings manufacturers.
ASTM G-21 is the standard practice for determining resistance of synthetic polymeric materials to fungi.
It is a test method that subjects specimens to lab conditions ideal for supporting microbial growth.
The spore suspension is a mixed solution of Aspergillus niger, Penicillium pinophilum, Chaetomium globosum, Gliocladium virens and Aureobasidium pullulans fungi, designed to demonstrate broad-spectrum mold inhibition.
ASTM D-3273/3274 is the standard test method for resistance to growth of mold on the surface of interior coatings in an environmental chamber.
It is a test designed to simulate a more realistic environment for microbial attack in indoor environments.
The mold suspension used is a mixed culture of Aureobasidum pullulans, Aspergillus niger and Penicillium. The mold naturally sporulates and reproduces, growing on any viable surface including the test panels.
Tests of this nature should always be performed at independent, certified laboratories, in accordance with published, recognized testing standards; interpretation of the test results should come directly from the testing laboratory.
Scott DeLeo is product manager for Fiberlock Technologies, Inc. (www.fiberlock.com), which produces antimicrobials and coatings for mold remediation.