MCQ AND MCA

摘要

The second category of preservatives includes wood treated with two variations of ACQ and CA: micronized copper quaternary (MCQ) and micronized copper azole (MCA). Unlike with ACQ and CA, in which the copper is dissolved chemically in an organic solvent, the copper in MCQ and MCA is present in microscopic particles suspended in water. Significantly, this makes the copper less corrosive to fasteners and hardware than the copper in wood treated with ACQ and CA; moreover, it can be placed in contact with aluminum. Another advantage is that wood treated with MCQ and MCA keeps more of its natural color. MCA- and MCQ-treated wood has not been tested by the AWPA. Instead, manufacturers have sent their products to the International Code Council Evaluation Service (ICC-ES), which provides research reports on innovative building products that it deems equivalent to standardized products. For each product, the ICC-ES report provides a minimum retention level. The labels for these products, however, usually just state "above ground," "ground contact," or "ground contact / freshwater use," which correspond to progressively higher retention levels.