When selecting acoustic cement boards, prioritize the Noise Reduction Coefficient (NRC), which should ideally be between 0.75 and 0.95 for high-performance environments. Ensure the board density is optimized for both sound absorption and structural durability; typically, a thickness of 15mm to 25mm is standard for commercial use. Additionally, verify the Fire Rating, seeking products that meet Class A (non-combustible) standards such as ASTM E84 or EN 13501-1 to ensure safety compliance in public buildings.