Ventilation and Depressurization Information for Houses Undergoing Remodeling

The overall objective of this study was to provide information on ventilation needs and depressurization concerns for existing houses in Minnesota that are being “tightened”.  The results were obtained from indoor air quality (IAQ) test data and survey results from houses near the Minneapolis-St. Paul International Airport.  Pre and post-construction IAQ test data from sound treated houses was analyzed to determine the necessity for mechanical ventilation for different housing types, the frequency of combustion spillage problems, and the frequency of depressurization problems.  In addition, a random sample of south Minneapolis homeowners were surveyed as to their perceptions of the quality of the air, comfort level of their house, and operation of their ventilation systems.  For a portion of those homeowners their house was visited to document the performance of existing ventilation systems, inspect for moisture concerns, and obtain further homeowner information regarding the IAQ in their home.

Over 7,000 houses near the Minneapolis-St. Paul International Airport have been treated by a Sound Insulation Program (SIP) funded by the Metropolitan Airports Commission.  The treatments are similar to those measures used for remodeling or to improve the energy efficiency of a house.  The resulting tightening of the houses raises concerns regarding a variety of IAQ issues including inadequate ventilation and combustion gas spillage.  This is particularly true since many of the houses have pre-existing combustion safety and moisture problems.  Due to these concerns, the SIP has developed a comprehensive, three-step process to assure that acoustic treatments do not have a negative impact on the IAQ of a house.  This approach emphasizes the installation of moderate capacity ventilation systems to offset the effect of house tightening and thorough tests to assure that appliances do not spill combustion gases into the house under worst case conditions. 

Full report (PDF):
Ventilation and Depressurization Information for Houses Undergoing Remodeling