Testing performed by The MicroStar Lab

Modified ASTM D3273
Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber
This test utilizes a pan of moldy soil in a high humidity, warm temperature chamber that continuously releases fungal spores to challenge test pieces suspended above the soil. A sample is defined as 3 test pieces, 3” x 4” with each piece labeled with the sample designation from the customer. Since the ASTM D3274 photographic standard that was originally designated for the rating scale is in the process of being changed and no longer applies to the D3273, a modified rating scale is used. However, since the original rating scale utilized a 50-100X examination of the test pieces, all test pieces are still examined stereoscopically when rated unless otherwise requested by the customer. The rating scale still uses the 0-10 range with 10 being clean and 0 being completely covered with growth. The “9” rating is 10% coverage or less; “8” is coverage between 10-20%, etc. All customer samples are tested in their own individual test chamber, eliminating the opportunity for cross-contamination between customer tests. Custom modifications to the inoculum are available, but will increase the turn-around time by an additional 4-5 weeks. Upon the customer’s request, a 9* rating will also be included in the scale, identifying test pieces that show less than 1% fungal growth on the surface. Upon the customer’s request, test pieces will be examined with a lighted hand lens and not the stereoscope, but the report will make note of this rating modification. If a customer wishes to have test pieces returned, an additional cost will be charged and the test pieces will be autoclaved prior to shipment. Temperature and humidity are monitored with instrumentation that has been calibrated with NIST-traceable standards. The ASTM D3273 is a 4-week test and results are usually available 5 weeks after testing begins.