Effectiveness of an Aerosol Sealant to Reduce Multifamily Air Leakage
An innovative aerosol sealing process has been developed to significantly reduce multifamily building envelope air leakage. The technology was adapted from an established process for sealing duct leaks. For envelope sealing, an aerosol sealant is sprayed into an apartment unit that is pressurized by fans installed in a hallway or an exterior door. As the air and sealant particles are forced through leaks, the sealant sticks to the edges of the gaps and gradually fills the openings. A field demonstration and modelled study has been conducted to measure envelope air leakage reduction and estimate energy savings for air sealing new and existing multifamily units in Minnesota buildings using the aerosol process. A total of 18 units were sealed in three new construction buildings. The sealing process typically required 60 to 90 minutes of injection and resulted in envelope leakage reductions of 67% to 94%. The envelope leakage ranged from 0.2 to 1.4 ACH50 with half of the units achieving a leakage more than 80% below the code requirement of 3.0 ACH50. EnergyPlus models for four different ventilation strategies in new and existing buildings showed space heating energy savings of 4% to 25%. Nine units were sealed in three existing multifamily buildings. Pre-seal tests showed air leakage levels two to five times greater than that for the new construction, resulting in longer sealing times. However, the air sealing still achieved similar relative leakage reductions of 39% to 89% and greater reductions in absolute leakage and energy use.
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