Chapter 21 Cladding with Metal Glass Metal Glass

Chapter 21 Cladding with Metal & Glass

Metal & Glass Curtain Walls Connected to , but isolated from, the building frame èSupport only their weight & resist lateral forces Insulated & thermally broken èMaximize comfort, minimize H/C costs & condensation Incorporate advanced glazing & spandrel materials (luminous & thermal properties) Gaskets & drainage to prevent water infiltration Architectural appearance & ease of installation èInternal features, fasteners, etc. … concealed èMultiple extrusion shapes, finishes, & colors

Metal Frames - Extrusions Aluminum - the metal of choice èDoesn’t corrode (beyond a thin oxidized layer) èCan accept, and hold, a variety of finishes èEconomically fabricated - extruded (multiple shapes)

Extrusion Heated metal is forced through a die Continuous ribbon of material Highly precise cross-section Multiple shapes available Die

Extrusion

Thermal Breaks Aluminum - not a good insulator èCold climates - inside metal cold w Interior condensation (even frost) èHot climates - metal cooled by AC w Exterior condensation System Needs - Thermal Break

Thermal Break Definition è“internal components of insulating material that isolate the aluminum on the interior side of the component (mullion) from aluminum on the exterior face” Construction (rubber or plastics) Thermal Break

Thermal Breaks

Aluminum Finishes Natural oxidized finish - not attractive Applied Coatings èAnnodized coatings èOrganic coatings w Multi-coat sprayed èPowder Coatings w sprayed powder - baked èPolyvinyl chloride (PVC) èMechanical Finishes w brush, sandblast, polish, etc.

Annodized Coatings Oxidized coating produced in an acid bath Additives can produce a number of colors èMost common - bronzes Advantages: èExtremely hard coating èVery good resistance to weather & fading Disadvantage: color consistency

Sampling of Mullion Colors Aluminum & Glass L. C.

Assembly Components Mullions Shear Blocks Screws Gaskets “Snap-ons”

Modes of Curtain Wall Assembly Stick Systems Unit System Panel Systems Column Cover & Spandrel System

Stick Systems Components • Vertical Mullions • Horizontal Mullions • Glass Panels • Spandrel Panels Assembly • In the “Field” Advantages • Minimal shipping bulk • Latitude for field adj. • “Hand” set components • Economical Disadvantages • Built on “site” • Quality Control

‘Stick’ Systems

Unit Systems Components • Pre-assembled Framed Unit Assembly • Factory Assembly • Field unit installation Advantages • Minimizes on-site labor • Factory - “controlled” Disadvantages • Larger shipping bulk • Site protection of mat’l • Heavier wgt. - cranes?

Panel Systems Components • Homogenous units • Formed from sheet metal Assembly • Fabrication - shop • Field installed Advantages • Minimizes on-site labor • Factory - “controlled” Disadvantages • $ of custom molds • Larger shipping bulk • Site protection of mat’l • Heavier wgt. - cranes?

Column Cover & Spandrel “emphasizes the structural module of the building” Components • Column Covers • Spandrel panels • Glazing units Assembly • Field installation Disadvantages • Field Assembly • $ for custom design (no “standard” blg. module)

Column Cover & Spandrel

Types of Glazing Outside Glazed “Glass installed (or replaced) from the outside” èSimple mullion system èTypically more economical on low-rise blgs. Inside Glazed “Glass installed (or replaced) from the inside” èMore elaborate mullion components/system w Higher material costs èTypically more convenient & economical on tall buildings w Lower field labor costs

Snap Cover Outside glazed “stick” system Shear Block Thermal Break Pressure Plate

Stick system “externally” glazed Thermal Break Interior Gaskets Pressure Plate

One Piece Extrusion Two Piece Extrusion

Building Anchorage Mullion “Splicing”

Inside Glazed

Inside Glazed continued Bottom Half of the Horizontal Mullion Installed after Glass Installation

Expansion Joints Metal and Glass Aluminum èHigh coefficient of thermal expansion èTwice the coefficient of Glass Aluminum to Glass expansion / contraction èGaskets èBlocks (spacers) keep glass form Walking w/i opening Aluminum mullion Expansion / Contraction èTelescoping joints in vertical mullions èHorizontal mullions cut slightly short

Sloped Glazing - Skylight

Sloped Glazing - Skylight

Unique Problems w/ Sloped Glazing • Gravity “pulling” H 2 O thru the “System” • Internal Condensation • Both can cause • discomfort - occupants • damage Solution • “Internal Drainage System

Sloped Glazing - Skylight

Cladding In Metal

Sheets of Copper

Stainless Steel

SS Jointing

Painted Metal Panels

Metal Panels

Aluminum Panels

Aluminum Panel Column Covers

Aluminum Panel Column Covers

Aluminum Panels

Experience Music Project ‘Rock n Roll Museum’ Seattle (6 photos) Stainless Steel, Copper, and Coated Metal Panels

Curtain Wall Design Complex & Specialized Process (often a proprietary system adopted that meets design criteria) Design ‘specialists’ consulted Concept drawings prepared by A&E Detailed design documents prepared by manufacturer – followed by shop dwgs. A/E reviews to ensure design compliance Full-scale testing Manufacturer and then erection

Sustainability in Aluminum Cladding Raw material plentiful, but refining requires considerable energy (embodied energy 6 x steel) Large quantities of water required for smelting & waste water contains pollutants Aluminum recycled at a very high rate Extrusions easy to produce and light weight Powder coating release no solvents into the atmosphere Low maintenance, but highly conductive (thermal breaks required)