This proposed addendum would require HVAC systems covered by Section 6.7 to be designed to accommodate the pressure drop imposed on them by the installed filters to ensure that sufficient airflow is not inhibited. This proposed change includes a requirement to provide the needed information on design airflow and maximum allowable clean filter pressure drop so that the filter can be replaced properly. Since the needed information on clean filter pressure drop is not routinely available at present, the proposed change would not take effect until January 1, 2014.