A4220 Enclosures and Environments I
Technology RequirementAnthony Webster
COURSE DESCRIPTION
The course begins with a brief historical introduction to building envelopes. The evolution of the building envelope is outlined in terms of : the functions it performs; the atmospheric conditions it mediates between, its relationships to other building-perimeter systems, and the principles of physics and properties of materials employed to perform its functions.
Both design projects and case-study analyses are given throughout the semester in the form of home-works. In addition to their use in building the student's understanding of building envelopes, these exercises illustrate how technical-utilitarian systems have been used to create technically striking structures, and they encourage students to consider the potential of technical-utilitarian systems to inform the spaces and formal expression of their own designs.
TOPICS
Historical trajectories of the building envelope
- The evolving concept of shelter rain and snow, wind, temperature, humidity, security and electromagnetic shielding.
- Building envelope vs. Building perimeter the relationships between the building's skin, structure, and environmental conditioning systems
- Contemporary envelope design criteria strategies for deciding what has to be done, and what else could be beneficial
Factors affecting envelop design & performance
- Environmental forces on the building envelope : the sun, the earth and the atmosphere
- Physical properties of building components and atmospheres : strength and stiffness; water resistance, thermal expansion, resistance, capacity and feel; Humidity; Changing states
- Mechanisms of heat transfer : radiation, conduction, convection
- Human comfort : Psychrometrics, MRT
- Water and Air movement across the building envelope
Design goals water out, fresh air in, pressure differentials, water vapor constrained
Air and water physics requirements for water to cross the envelope; force moving water through envelope; forces moving vapor through envelope (the dew point disaster)
Design strategies controlling vapor movement; maintaining pressure differentials; water barriers and rain-screens
- Heat Flow through the building envelope
Design goals maintaining the thermal comfort zone
Design strategies geometric effects; earth and atmospheric boundaries (walls, roofs, foundations); using radiation, conduction, convection, thermal capacity, changing states, inductance to your advantage; Trombe walls, water tanks, buffers, reflecting pools, exterior insulation
R-values etc. Determining external cooling loads; heating loads
- Structural functions of the envelope : resisting gravity and wind forces
Building Envelope systems: Wall systems
- Monolithic walls : masonry and platform frame construction
- Cavity walls : the first rain-screen principle system
- Cast-iron facades : between load bearing and curtain-wall
- Frame and infix : Starett-Lehigh to Battery Park City
- Frame and exfill : cantilevering the rainscreen
- Curtain-walls : inventing a new structure for the facade system
Building Envelope systems: Roof and Ground systems
- Flat and pitched roofs : membrane roofs
- Pitched roofs : shingles, standing seam, skylights
- Enclosure floors and basements : framed slabs, slabs on grades, below grade walls, etc.