In following the Sheet Metal and Air Conditioning National Contractors Association (SMACNA) Indoor Air Quality...

According to the Sheet Metal and Air Conditioning National Contractors Association (SMACNA) Indoor Air Quality (IAQ) Guidelines for Occupied Buildings under Construction, the Minimum Efficiency Reporting Value (MERV) as determined by ASHRAE 52.2-2007 required for renovation activities is MERV 13. This requirement is in place to ensure that the air filtration systems used during renovation activities are capable of capturing fine particles, thus reducing the risk of indoor air quality issues. MERV 13 filters are efficient at capturing particles that are 0.3 to 1.0 micrometers in size, including dust, pollen, mold spores, bacteria, and any other airborne contaminants that might be present during construction activities.References:SMACNA IAQ Guidelines for Occupied Buildings Under Construction, 2nd Edition 2007; ASHRAE Standard 52.2-2007, "Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size."