This webinar is sponsored by the Academy of Architecture for Health (AAH) on May 9, 2017 from 2–3pm ET. Earn 1.0 AIA LU/HSW. This presentation is a primer on building science as it relates to the exterior enclosure with particular emphasis on the air barrier. Air barriers play an important...
- • 2015 - Continuous air barrier required throughout the building envelope (except Climate Zone 2B Air Movement & Barriers Code Requirements – Opaque Envelope Allowable air leakage at 0.3 in. w.g. (75 Pa) Material: 0.1 perm 1.0 perm <=10 perm Additional Considerations Vapor Diffusion • Very slow process (less than airflow) • Vapor retarders control diffusion • Can be combined with air barrier and/or moisture barrier • Should be located on the “warm” side of the wall • Only one vapor retarder per wall assembly Additional Considerations Vapor Diffusion Common Vapor Retarders: Polyethylene film Fluid-applied vapor retarder Self-adhering sheet membranes Aluminum foil/FSK “Smart” vapor retarders Other Materials that Serve as Vapor Retarders Oil and epoxy based paints Polystyrene board insulation (XPS) Vinyl wall coverings Sheet metal & glass Additional Considerations Vapor Diffusion Insulation in Stud Space Hybrid System Insulation in Cavity “Cold” Climate “Hot” or “Cold” Climate Additional Considerations Vapor Retarder Placement Warm/humid climate “Smart” vapor retarder Perforated vinyl wall covering “The product is not suited for cooling climates with high outdoor humidities… Do not use with vinyl wall coverings or vapor retarding paints” - Manufacturer’s Literature Additional Considerations Vapor Diffusion Issues: Hot Climate Condensation on sheathing Vapor retarder on cold side of insulation Additional Considerations Vapor Diffusion Issues: Cold Climate Building Enclosure Fundamentals Summary Air barriers serve to reduce energy consumption and help mitigate moisture issues with the building envelope Continuity, integration, and compatibility are key to air barrier design, installation, and performance Performance of healthcare building enclosures are dependent on the performance of not only the air barrier, but also moisture barrier, thermal barrier, and vapor retarder Thermal barrier code changes as well as interior design conditions make healthcare facilities especially susceptible to increased risk of condensation Time for Questions and Comments Moderator John Kreidich McCarthy Building Cos