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...
- Building Science Basics Enclosure Problems Building Science Basics Overview Involved in all aspects of the building enclosure design Principles relate to structures everywhere Key to understanding moisture problems Primary goals are to reduce energy costs & prevent moisture problems Building Science Basics Overview • Air movement • Air barriers • Drying and moisture transport • Heat energy movement • Insulation effect & placement • Material conductivity • Moisture problems • Water leakage • Vapor diffusion Building Enclosure Fundamentals Air Barriers for Health Care Facilities Air Barriers Air Movement & Barriers Air Flow Concepts Air Movement • High to low pressure • Pressurization affected by: – Wind effects – Mechanical systems – Stack effect • Transports: Heat & Vapor Air Movement & Barriers Wind Pressurization • External Pressures – Windward – Leeward • Internal Pressures – Positive and negative pressure – Affected by: Building type (open, closed, partially enclosed) External Pressures Internal Pressures (per ASCE 7) Enclosure Classification (Gcpi) Open Buildings 0.00 Partially Enclosed Buildings +/- 0.55 Enclosed Buildings +/- 0.18 Windward Pressure Leeward Pressure WIND Air Movement & Barriers Mechanical Pressurization Exhaust Negative Internal Pressure Outside Air Air Movement & Barriers Mechanical Pressurization Positive Internal Pressure Outside Air Exhaust Air Movement & Barriers Mechanical Pressurization Return Air (Vent Restricts Airflow) Fan Vent SupplyReturn Air Movement & Barriers Mechanical Pressurization Stack Effect: Hot Climate COOL Stack Effect Air Movement & Barriers Mechanical Pressurization Stack Effect: Cold Climate WARM COLD Stack Effect Air Movement & Barriers Barrier Definition Air Barrier Materials assembled and joined together to provide a barrier to air leakage through the building envelope. An air barrier may be a single material or a combination of materials. - 2015 IECC Air Movement & Barriers Air Barrier Requirements Continuous across thermal envelope Joints & seams sealed