1 Scope

NOTE This standard governs the design, fabrication, finishing, and installation of aluminum-framed glazed curtain wall serving as the primary non-load-bearing exterior enclosure of a building. (1.1)

NOTE A curtain wall is defined by what it does structurally: it carries no floor or roof load, it spans vertically across one or more stories, and it transfers only its own weight and the wind acting on its face back to the building frame at discrete anchors. That is the property that separates it from a storefront, which bears on the slab within a single story, and from a window wall, which stacks within each story between the slab above and the slab below. (1.2)

NOTE The work of this standard includes the extruded aluminum framing and its thermal barrier, the glazing infill and the means that retains it, the internal drainage and pressure-equalization provisions, the anchorage back to the building structure, the movement joints, and the perimeter air and water seals that tie the wall into the surrounding enclosure. (1.3)

NOTE Because the wall hangs across the floor edge, it resists wind, excludes water and air, controls heat flow and condensation, and absorbs the building's movement at the same time and through the same members. A change made for one of those purposes moves the others, so the wall is designed, tested, and accepted as one engineered system rather than as a collection of parts. (1.4)

NOTE The following are governed elsewhere and are outside this standard: (1.5)

the glass and insulating glass units where they are specified independently of a framing system, including monolithic glazing set into other assemblies (GlazingGlass and GlazingResolves to the current edition.sync/glazing)
ground-floor entrances, entrance doors, and the storefront framing that receives them (Aluminum Entrances And StorefrontsAluminum Entrances and StorefrontsResolves to the current edition.sync/aluminum-entrances-and-storefronts)
the building air barrier and the transition membranes beyond the curtain wall perimeter (Air BarriersAir BarriersResolves to the current edition.sync/air-barriers)
joint sealants outside the curtain wall perimeter joint (Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants)
sheet metal flashing, copings, closures, and trim outside the curtain wall frame (Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current edition.sync/sheet-metal-flashing-and-trim)
thermal insulation in the back-up construction behind spandrel areas (Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation)
window wall, punched windows, operable windows, sloped glazing, skylights, and point-supported structural glass assemblies
the structural frame, embedded plates, and cast-in anchors furnished under the structural work, up to the face at which the curtain wall anchor connects

NOTE This standard carries its own glazing selection tree because the framing system and the glazing infill are delivered, tested, warranted, and accepted as one product under one performance rating. Glass selected apart from the frame that holds it cannot be assigned an air, water, structural, or thermal rating. (1.6)

1.7 The extent, elevations, and mullion grid of the curtain wall shall be as indicated on the exterior elevations and curtain wall details.

1.8 Vision, spandrel, and opaque infill areas shall be located as indicated on the exterior elevations.

1.9 Glass types shall be keyed to each lite as indicated on the glazing schedule.

1.10 Anchor locations and the supporting structure at each floor shall be as indicated on the project structural drawings.

1.11 Penetrations of the curtain wall for louvers, vents, grilles, and equipment shall be located as indicated on the exterior elevations and the mechanical plans.

2 Referenced Standards

2.1 Materials, fabrication, testing, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

2.2 Where two referenced standards, the contract documents, or the Authority Having Jurisdiction impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

2.3 The adopted building code and the adopted energy code shall take precedence over every other reference on any matter those codes address directly.

Standard	Title
AAMA/WDMA/CSA 101/I.S.2/A440	North American Fenestration Standard/Specification for Windows, Doors, and Skylights
AAMA CW-DG-1	Aluminum Curtain Wall Design Guide Manual
AAMA CW-RS-1	The Rain Screen Principle and Pressure-Equalized Wall Design
AAMA CW-10	Care and Handling of Architectural Aluminum from Shop to Site
AAMA CW-13	Structural Sealant Glazing Systems
AAMA 501	Methods of Test for Exterior Walls
AAMA 501.1	Standard Test Method for Water Penetration of Windows, Curtain Walls and Doors Using Dynamic Pressure
AAMA 501.2	Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls, and Sloped Glazing Systems
AAMA 501.4	Recommended Static Test Method for Evaluating Curtain Wall and Storefront Systems Subjected to Seismic and Wind Induced Inter-Story Drift
AAMA 501.5	Test Method for Thermal Cycling of Exterior Walls
AAMA 501.6	Recommended Dynamic Test Method for Determining the Seismic Drift Causing Glass Fallout from a Wall System
AAMA 501.7	Recommended Static Test Method for Evaluating Curtain Wall and Storefront Systems Subjected to Vertical Inter-Story Movement
AAMA 503	Voluntary Specification for Field Testing of Newly Installed Storefronts, Curtain Walls, and Sloped Glazing Systems
AAMA 507	Standard Practice for Determining the Thermal Performance Characteristics of Fenestration Systems in Commercial Buildings
AAMA 611	Voluntary Specification for Anodized Architectural Aluminum
AAMA 800	Voluntary Specifications and Test Methods for Sealants
AAMA 1503	Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors, and Glazed Wall Sections
AAMA 2603	Voluntary Specification, Performance Requirements and Test Procedures for Pigmented Organic Coatings on Aluminum Extrusions and Panels
AAMA 2604	Voluntary Specification, Performance Requirements and Test Procedures for High Performance Organic Coatings on Aluminum Extrusions and Panels
AAMA 2605	Voluntary Specification, Performance Requirements and Test Procedures for Superior Performing Organic Coatings on Aluminum Extrusions and Panels
ASCE 7	Minimum Design Loads and Associated Criteria for Buildings and Other Structures
ASTM B209	Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
ASTM B221	Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
ASTM A123	Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
ASTM C920	Standard Specification for Elastomeric Joint Sealants
ASTM C1036	Standard Specification for Flat Glass
ASTM C1048	Standard Specification for Heat-Strengthened and Fully Tempered Flat Glass
ASTM C1087	Standard Test Method for Determining Compatibility of Liquid-Applied Sealants with Accessories Used in Structural Glazing Systems
ASTM C1135	Standard Test Method for Determining Tensile Adhesion Properties of Structural Sealants
ASTM C1172	Standard Specification for Laminated Architectural Flat Glass
ASTM C1184	Standard Specification for Structural Silicone Sealants
ASTM C1249	Standard Guide for Secondary Seal for Sealed Insulating Glass Units Used in Structural Sealant Glazing Applications
ASTM C1401	Standard Guide for Structural Sealant Glazing
ASTM E90	Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
ASTM E119	Standard Test Methods for Fire Tests of Building Construction and Materials
ASTM E283	Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences
ASTM E330	Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights, and Curtain Walls by Uniform Static Air Pressure Difference
ASTM E331	Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference
ASTM E413	Classification for Rating Sound Insulation
ASTM E783	Standard Test Method for Field Measurement of Air Leakage Through Installed Exterior Windows and Doors
ASTM E1105	Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference
ASTM E1300	Standard Practice for Determining Load Resistance of Glass in Buildings
ASTM E1332	Standard Classification for Rating Outdoor-Indoor Sound Attenuation
ASTM E1886	Standard Test Method for Performance of Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Missile(s) and Exposed to Cyclic Pressure Differentials
ASTM E1996	Standard Specification for Performance of Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Windborne Debris in Hurricanes
ASTM E2188	Standard Test Method for Insulating Glass Unit Performance
ASTM E2190	Standard Specification for Insulating Glass Unit Performance and Evaluation
ASTM E2307	Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-story Test Apparatus
ANSI Z97.1	Safety Glazing Materials Used in Buildings — Safety Performance Specifications and Methods of Test
16 CFR Part 1201	Safety Standard for Architectural Glazing Materials
IBC	International Building Code
IECC	International Energy Conservation Code
ASHRAE 90.1	Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings
NFPA 285	Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components
NFRC 100	Procedure for Determining Fenestration Product U-factors
NFRC 200	Procedure for Determining Fenestration Product Solar Heat Gain Coefficient and Visible Transmittance at Normal Incidence

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for review and shall not release any curtain wall component for fabrication until the corresponding submittal has been reviewed and returned:

shop drawings giving scaled elevations of every curtain wall condition, with the mullion grid, transom lines, floor lines, movement joints, vision and spandrel areas, and the glass type designation of each lite
shop drawing sections and plans at the head, sill, base, jamb, typical vertical mullion, typical horizontal, floor-edge anchor, spandrel, outside and inside corner, movement joint, and every transition to an adjacent enclosure assembly
shop drawing details showing the thermal barrier, the glazing pocket and its retention, the gasket compression or the structural silicone bite and glue-line, the drainage and pressure-equalization path, the perimeter sealant joints, and the continuity of the air and water control layers
product data for the framing system, giving the tested air, water, structural, and thermal ratings of the system as configured for this project
product data for the gaskets, sealants, thermal barrier material, setting blocks, anchors, fasteners, and finish
product data for each glazing makeup, giving the lite thicknesses, heat treatment, coating and coating surface, interlayer, cavity gas, edge spacer, and the certification the unit carries
finish samples not less than 12 in. by 12 in. on the extrusion profile that will be used, or on a profile of equivalent thickness, showing color, gloss, and texture
for an anodized finish, a set of samples showing the full lot-to-lot color range that will be accepted across the facade
a glazing sample of each vision and spandrel makeup, not less than 12 in. by 12 in., showing color, coating appearance, and frit or opacifier pattern

Action Submittal Packagecheckbox

☐ Curtain wall shop drawing elevations

☐ Shop drawing sections, plans, and anchor details

☐ Framing system product data with tested ratings

☐ Gasket, sealant, thermal barrier, and anchor product data

☐ Glazing makeup product data

☐ Finish samples on the extrusion profile

☐ Anodized lot-to-lot color range samples

☐ Vision and spandrel glazing samples

3.1.2 The framing, glazing, anchorage, and structural submittals shall be assembled into one coordinated review package so that mullion depths, glazing pocket geometry, glazing unit thickness and weight, anchor preparations, and movement provisions are reconciled against one another before any component is fabricated.

3.1.3 A partial submittal that defers any one of those items to a later package shall be returned without review.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following supporting calculations, test reports, and certifications with or before the action submittals:

structural calculations for the framing, the glazing retention, and the anchorage, signed and sealed by a professional engineer licensed in the project jurisdiction
laboratory test reports for the system as configured for this project, covering air infiltration, static water penetration, dynamic water penetration, and structural performance
thermal transmittance and condensation resistance results for the framing and for the complete product, by the determination method specified in this standard
certified whole-product U-factor, solar heat gain coefficient, and visible light transmittance where the adopted energy code requires a certified rating
seismic interstory drift, vertical interstory movement, and thermal cycling test reports where those tests are required by this standard
missile impact and cyclic pressure test reports where impact resistance is required by this standard
structural silicone adhesion and compatibility results for the specific glass coating, framing finish, setting blocks, spacers, gaskets, and every other material the structural sealant will contact
the listing for the perimeter fire containment system, identifying the tested assembly and the ratings it achieved
the listing for the exterior wall assembly where compliance with NFPA 285 is required by this standard
thermal movement calculations for the framing and the movement joints, using the temperature ranges specified in this standard
qualification records for the manufacturer, the fabricator, and the erector
the structural sealant manufacturer's written approval of the glazier for the specific system

Informational Submittal Packagecheckbox

☐ Signed and sealed structural calculations

☐ Laboratory air, water, and structural test reports

☐ Thermal transmittance and condensation resistance results

☐ Certified U-factor, SHGC, and VLT ratings

☐ Seismic drift and thermal cycling test reports

☐ Missile impact and cyclic pressure test reports

☐ Structural silicone adhesion and compatibility results

☐ Perimeter fire containment system listing

☐ NFPA 285 assembly listing

☐ Thermal movement calculations

☐ Manufacturer, fabricator, and erector qualification records

☐ Glazier approval by the structural sealant manufacturer

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the curtain wall is accepted:

as-built elevations recording every field change to the mullion grid, glass types, anchorage, and movement joints
mockup test reports, including each deficiency found, the corrective action taken, and the date production fabrication was released
field water and air test reports, identifying each location tested, the pressure applied, and the result
cleaning and maintenance instructions for the framing finish, the glass, the gaskets, and the sealants, naming the products approved for cleaning and the products that shall not contact the finish or the glass coatings
a re-glazing procedure identifying the sequence, the parts, and the special tools needed to replace a single lite without disturbing adjacent lites
warranty documentation from the curtain wall manufacturer, the finish applicator, the insulating glass fabricator, and the structural sealant manufacturer where structural silicone glazing is used
a signed receipt from the Owner for the extra stock materials delivered

Closeout Submittal Packagecheckbox

☐ As-built elevations

☐ Mockup test reports and corrective action record

☐ Field water and air test reports

☐ Cleaning and maintenance instructions

☐ Re-glazing procedure

☐ Warranty documentation

☐ Extra stock receipt

4 Quality Assurance

4.1 Manufacturer, Fabricator, and Erector Qualifications

4.1.1 The curtain wall manufacturer shall have produced aluminum curtain wall systems of the type and performance specified for not less than ten years.

4.1.2 The curtain wall manufacturer shall furnish independent laboratory test reports for the specific system, at the configuration and the design pressure required by this project, demonstrating the air, water, and structural performance this standard requires.

4.1.3 The fabricator shall have fabricated curtain wall of comparable scope, height, and complexity for not less than five years.

4.1.4 The erector shall have erected curtain wall of comparable scope, height, and complexity for not less than five years.

4.1.5 Where the Contractor proposes a manufacturer, fabricator, or erector whose record does not meet these criteria, the Engineer of Record shall make the initial determination whether the proposed record is equivalent, and shall do so in writing before the subcontract is awarded.

4.2 Delegated Structural Design

4.2.1 The framing member sizing, the glazing retention design, the connection design, and the anchorage design shall be performed by a professional engineer licensed in the project jurisdiction and engaged by the curtain wall contractor.

4.2.2 The structural calculations shall be signed and sealed by that engineer and shall demonstrate compliance with the design wind pressures, deflection limits, and movement criteria this standard and the contract documents establish.

4.2.3 The calculations shall address the mullion spans and deflections, the mullion reinforcement, the distribution of glass load into the framing per ASTM E1300, the capacity of every anchor condition, and the accommodation of thermal movement and interstory drift.

4.2.4 Where structural silicone glazing is used, the calculations shall size the structural bite and the glue-line thickness for the wind load and for the dead weight of the glass carried by the sealant.

NOTE The curtain wall is a delegated design in most jurisdictions: the contract documents fix the geometry, the performance criteria, and the design pressures, and the specialty engineer completes the member sizing, connection design, and anchorage within those criteria. The design responsibility boundary follows that split, which is why the criteria in this standard are written as targets the specialty engineer designs to rather than as member sizes. (4.2.5)

4.3 Structural Silicone Glazing Quality Program

4.3.1 Where structural silicone glazing is used, the glazier shall hold written approval from the structural sealant manufacturer for the specific system, issued before any structural sealant is applied.

4.3.2 The structural sealant manufacturer shall review the structural joint design, confirm substrate adhesion and compatibility before production begins, and provide on-site instruction at the start of structural glazing.

4.3.3 Adhesion and compatibility shall be verified per ASTM C1135 and ASTM C1087 for the specific glass coating, the specific framing finish, the setting blocks, the spacers, the gaskets, and every other material the structural sealant will contact.

4.3.4 The insulating glass unit secondary seal used behind a structural silicone bead shall conform to ASTM C1249.

4.3.5 A written quality control record shall be kept for each production run, recording the sealant lot number, the mixing verification for a two-part sealant, the cure verification, the bead dimensions, and the results of the daily adhesion tests.

4.3.6 The Contractor shall bear the cost of every adhesion, compatibility, and cure test required by this program, and the cost of re-testing after any failure.

4.3.7 Structural sealant shall not be loaded, handled, shipped, or glazed into the building until it has reached the cure the sealant manufacturer publishes for the section applied.

NOTE In a structurally glazed wall the silicone is the load path that holds the glass on the building, because the bonded edges carry no mechanical capture. An adhesion or cure failure that goes undetected is a fallout hazard rather than a leak, and it cannot be found by inspecting a cured, glazed unit from either face — which is why the verification is front-loaded into the production process instead of the finished product. (4.3.8)

5 Design Wind Pressures

5.1 The curtain wall, its glazing, its retention, and its anchors shall be designed for the inward and outward design wind pressures indicated in the datasheet.

Inward Design Wind Pressure at the Wall Field Zonerange

psf

152025304050607590110130150175200

Per drawings — as indicated on the project structural drawings (deferred by default)

Outward Design Wind Pressure at the Wall Field Zonerange

psf

152025304050607590110130150175200

Per drawings — as indicated on the project structural drawings (deferred by default)

Inward Design Wind Pressure at the Corner and Edge Zonesrange

psf

152025304050607590110130150175200250300

Per drawings — as indicated on the project structural drawings (deferred by default)

Outward Design Wind Pressure at the Corner and Edge Zonesrange

psf

152025304050607590110130150175200250300

Per drawings — as indicated on the project structural drawings (deferred by default)

5.2 Each portion of the wall shall be designed for the pressure of the zone in which it falls, and framing, glazing, and anchors within a corner or edge zone shall not be designed for the wall field pressure.

NOTE The design wind pressures are components-and-cladding pressures determined per ASCE 7 from the site wind speed, the building's risk category, its height, and its exposure, and they are established by the project's structural design rather than by the curtain wall contractor. The zone pressures differ because flow separation at corners, parapets, and roof edges produces local suctions several times the pressure acting on the middle of a wall, over a strip whose width ASCE 7 ties to the building's least horizontal dimension and its height. (5.3)

6 Structural Performance and Deflection Limits

6.1 The framing shall resist the inward and outward design wind pressures without permanent deformation, glass breakage, anchor distress, or loss of the air or water seal, verified per ASTM E330.

6.2 The system shall be subjected to a structural overload of 1.5 times the design wind pressure in each direction, after which no framing member shall retain a permanent deformation exceeding 0.2 percent of its clear span.

6.3 Framing deflection normal to the plane of the wall under the design wind pressure shall not exceed the limit indicated in the datasheet.

Framing Deflection Limit Normal to the Wallselect

L/175 of the clear span, or 3/4 in., whichever is less

L/240 of the clear span, or 3/4 in., whichever is less

L/175 for clear spans of 13 ft 6 in. and less, and L/240 plus 1/4 in. for longer spans

L/360 of the clear span, or 3/4 in., whichever is less

6.4 Deflection of a glass-supporting horizontal member under the dead load of the glass it carries shall not exceed the limit indicated in the datasheet.

Dead Load Deflection Limit of Glass-Supporting Horizontal Membersselect

L/360 of the span, or 1/8 in., whichever is less

L/500 of the span, or 1/8 in., whichever is less

1/16 in. maximum, independent of span

6.5 Framing deflection shall not, at the design wind pressure, reduce the glass edge engagement below the bite the glazing design requires, and shall not open the glazing pocket.

6.6 Framing members shall be sized to meet these limits on their own section and reinforcement, and shall not rely on the stiffness of the glazing infill.

NOTE Deflection limits on a curtain wall are serviceability criteria, not strength criteria: a mullion that deflects too far leaks and disengages its gaskets long before it approaches failure, and the extra deflection concentrates load into the glass edge and the glazing pocket. A tighter limit is chosen where the lites are large, where the infill is heavy or brittle, or where the interior finish abuts the framing closely enough that visible movement matters. (6.7)

7 Air Infiltration

7.1 Air infiltration through the fixed curtain wall shall be tested per ASTM E283 at a static pressure differential of 6.24 psf and shall not exceed the rate indicated in the datasheet.

Maximum Air Infiltration Raterange

cfm/ft²

0.010.020.030.040.06

7.2 The rate shall be measured over the gross wall area of the test specimen, including the perimeter of the specimen frame.

NOTE Air leakage is controlled at a continuous interior seal plane formed by the inner gaskets, the inner glazing seal, and the sealed framing joinery, which is why the air control layer of a curtain wall is detailed at the interior face rather than the exterior. Placing it there also keeps humid interior air out of the framing cavities, where it would otherwise condense against cold exterior aluminum and appear at the sill as what looks like a leak. (7.3)

8 Water Penetration Resistance

8.1 Water penetration shall be tested statically per ASTM E331 at the pressure indicated in the datasheet.

Static Water Penetration Test Pressurerange

psf

6.248101215202530

Derived — 20 percent of the inward design wind pressure at the wall field zone, not less than 6.24 psf (by default)

8.2 Water penetration shall be tested dynamically per AAMA 501.1 where the datasheet requires the dynamic test.

Dynamic Water Penetration Test per AAMA 501.1radio

● Required

○ Not required

8.3 The dynamic test shall be performed at the same test pressure and the same water application rate as the static test.

8.4 No uncontrolled water shall appear beyond the innermost plane of the wall during either test.

8.5 Water that enters the glazing pocket or the framing cavities shall be collected on internal gutters and drained back to the exterior, and shall not reach the interior face.

NOTE The static test applies a steady pressure across the specimen while water is sprayed at a fixed rate. The dynamic test applies the same water rate while a propeller or engine-driven air stream generates the pressure, which reproduces the fluctuating, turbulent pressures a wall actually sees and drives water into joints that a steady pressure leaves alone. The two tests find different defects, which is why a system is commonly asked to pass both. (8.6)

NOTE A test pressure set as a fraction of the design wind pressure keeps the water criterion proportional to the exposure the wall was designed for. Above roughly 20 psf the test stops discriminating between systems and starts measuring the test chamber, which is why the practical ceiling on a laboratory water test sits near that value even on walls designed for far higher wind pressures. (8.7)

9 Thermal Transmittance and Solar Control

9.1 The whole-product thermal transmittance and solar heat gain coefficient shall satisfy Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code for the compliance path the project uses.

9.2 The whole-product U-factor shall not exceed the value indicated in the datasheet.

Maximum Whole-Product U-Factorrange

Btu/h·ft²·°F

0.20.240.280.320.360.40.450.50.550.60.7

Derived — the Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code fenestration criteria for the project location and the compliance path the project uses (by default)

9.3 The whole-product solar heat gain coefficient shall not exceed the value indicated in the datasheet.

Maximum Whole-Product Solar Heat Gain Coefficientrange

0.150.180.20.220.250.280.30.350.40.450.50.60.7

Derived — the Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code fenestration criteria for the project location and the compliance path the project uses (by default)

9.4 The whole-product visible light transmittance shall be not less than the value indicated in the datasheet.

Minimum Whole-Product Visible Light Transmittancerange

0.10.150.20.250.30.350.40.450.50.60.7

9.5 Thermal performance shall be established by the determination method indicated in the datasheet.

Thermal Performance Determination Methodselect

Physical test of the framing and product per AAMA 1503

Two-dimensional thermal simulation per AAMA 507

Certified simulation and labeling per NFRC 100 and NFRC 200

NOTE The three determination methods are not interchangeable in what they produce. A physical AAMA 1503 test measures one framing section under one set of conditions and yields both a U-factor and a condensation resistance factor. An AAMA 507 simulation models the assembled product from validated component data and is what makes a site-built wall of many configurations tractable. An NFRC certified rating is a labeled, third-party-verified whole-product number, and it is the form most energy codes ask for when they require certified fenestration ratings. (9.6)

NOTE Solar heat gain and visible transmittance move together, because both are properties of the same coating stack on the same glass. Pushing the solar heat gain coefficient down without losing daylight is the entire purpose of a spectrally selective low-emissivity coating, and the ratio of the two values is the measure of how well a given coating does it. (9.7)

10 Condensation Resistance

10.1 The condensation resistance factor of the product, determined per AAMA 1503, shall be not less than the value indicated in the datasheet.

Minimum Condensation Resistance Factorrange

35404550556065707580

10.2 The Contractor shall submit, with the framing submittal, a comparison of the interior framing and glass surface temperatures at the winter design condition against the interior design dew point stated in the contract documents.

10.3 Where that comparison shows an interior surface temperature at or below the interior design dew point, the Contractor shall report the condition to the Engineer of Record in writing before fabrication.

NOTE Bare aluminum is a powerful thermal bridge. An unbroken mullion both wastes energy and drops the interior framing surface below the indoor dew point, producing condensation that streaks the glass, stains adjacent finishes, and over time corrodes the frame and supports mold growth on abutting materials. The thermal barrier interrupts the metal path so the interior surface stays above the dew point the building actually runs at. (10.4)

NOTE The condensation resistance factor is a single index derived from measured surface temperatures under one standardized condition, so it ranks products rather than predicting performance in a specific building. The value a project needs rises with the interior humidity it maintains and falls with the winter design temperature it sees — a natatorium, a hospital, a museum, or a food processing space carries a far higher interior dew point than an office, and the same framing that is dry in one is wet in the other. (10.5)

11 Acoustic Performance

11.1 Acoustic performance shall be rated on the basis indicated in the datasheet.

Acoustic Rating Basisselect

No acoustic rating required

Sound Transmission Class per ASTM E90 and ASTM E413

Outdoor-Indoor Transmission Class per ASTM E1332

Both Sound Transmission Class and Outdoor-Indoor Transmission Class

11.2 Where a Sound Transmission Class is required, the assembly shall achieve not less than the class indicated in the datasheet.

Minimum Sound Transmission Classrange

303235384042454850

11.3 Where an Outdoor-Indoor Transmission Class is required, the assembly shall achieve not less than the class indicated in the datasheet.

Minimum Outdoor-Indoor Transmission Classrange

25273032353740

11.4 The acoustic rating shall be established by test of the complete assembly, including the framing, the glazing, the perimeter seals, and any spandrel back-up construction within the tested specimen.

11.5 The framing seals and the spandrel back-up shall not bypass the rated glazing.

NOTE The two metrics weight the frequency spectrum differently. Sound Transmission Class is weighted toward speech frequencies and describes partitions between occupied spaces well. Outdoor-Indoor Transmission Class extends the measurement lower, where aircraft, rail, and truck traffic put most of their energy, and a wall can hold a high Sound Transmission Class while performing poorly against low-frequency exterior noise. Which metric to specify follows from what the wall is being asked to keep out. (11.6)

NOTE Acoustic performance in a glazed wall is dominated by the glazing makeup — asymmetric lite thicknesses, acoustic interlayers, and wider cavities all break the coincidence dip that a symmetric unit has. The framing contributes through the continuity of its seals and through the flanking path a spandrel back-pan can open between floors. (11.7)

12 Thermal and Seismic Movement Criteria

12.1 The framing, the glazing pockets, the movement joints, and the anchors shall accommodate the movements specified in this section without glass breakage, glass fallout, permanent deformation, seal rupture, or noise.

12.2 The seismic design provisions applicable to the curtain wall shall be those the adopted building code assigns to Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category.

12.3 Thermal movement shall be calculated over the design temperature changes indicated in the datasheet.

Design Ambient Air Temperature Change for Thermal Movementrange

°F

80100120140160

Design Metal Surface Temperature Change for Thermal Movementrange

°F

120140160180200220

12.4 The wall shall accommodate the design interstory drift indicated in the datasheet.

Design Interstory Driftrange

in

0.250.50.7511.251.522.534

Per drawings — as indicated on the project structural drawings (deferred by default)

12.5 The wall shall accommodate the design vertical movement of the supporting floor edges indicated in the datasheet.

Design Vertical Movement at the Floor Edgerange

in

0.250.3750.50.7511.52

Per drawings — as indicated on the project structural drawings (deferred by default)

12.6 Static interstory drift performance shall be verified per AAMA 501.4 where the datasheet requires that test.

Static Interstory Drift Test per AAMA 501.4radio

○ Required

○ Not required

Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the design interstory drift (by default)

12.7 Dynamic glass fallout performance shall be verified per AAMA 501.6 where the datasheet requires that test.

Dynamic Glass Fallout Test per AAMA 501.6radio

○ Required

○ Not required

Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the design interstory drift (by default)

12.8 Vertical interstory movement performance shall be verified per AAMA 501.7 where the datasheet requires a laboratory mockup that includes that test.

12.9 Drift shall be absorbed by glass-to-frame clearance, by a glazing pocket that permits the lite to rock or slide within the frame, or by articulated joints in the framing, rather than by transmitting the movement into the glass.

NOTE Because the wall is anchored to the structure at every floor and spans the floor edge, the horizontal movement of one floor relative to the next is imposed directly across the height of one panel. The wall has no choice about receiving that movement; the only design question is which element absorbs it. (12.10)

NOTE The two seismic tests answer different questions. The static AAMA 501.4 test imposes the design drift slowly and asks whether the wall still holds its seals and its glass afterward. The dynamic AAMA 501.6 test drives the wall at increasing amplitude until the glass falls out, and reports the drift at which that happened — a fallout threshold rather than a pass or fail against the design drift. Projects where falling glass is the governing risk, rather than water leakage after an event, are the ones for which the second test is written. (12.11)

NOTE Aluminum expands roughly twice as much as steel and about three times as much as concrete over the same temperature change, and a dark facade in full sun runs far hotter than the air around it. That is why the movement calculation uses a metal surface temperature change substantially larger than the ambient air temperature change: the mullion, not the weather station, sets the movement the joints must take. (12.12)

13 Wind-Borne Debris Impact Resistance

13.1 Whether impact resistance applies to this curtain wall shall be determined from Wind Borne Debris RegionWind Borne Debris RegionParameterEach project supplies its own value.wind-borne-debris-region together with the height of each glazed opening above grade.

13.2 The curtain wall shall provide the impact resistance indicated in the datasheet.

Wind-Borne Debris Impact Resistanceselect

Not required

Small missile impact per ASTM E1996

Large missile impact per ASTM E1996 Missile C

Large missile impact per ASTM E1996 Missile D

Large missile impact per ASTM E1996 Missile E

Derived — Wind Borne Debris RegionWind Borne Debris RegionParameterEach project supplies its own value.wind-borne-debris-region and the height of the glazed opening above grade (by default)

13.3 Impact-rated assemblies shall be tested per ASTM E1886 for missile impact followed by the cyclic pressure sequence, and shall comply with ASTM E1996 for the wind zone and missile level required.

13.4 The framing and its glazing retention shall hold the impacted lite in the frame through the entire cyclic pressure sequence.

13.5 The perimeter anchorage of an impact-rated assembly shall be designed for the loads the impact and cyclic pressure sequence imposes, and shall not be reduced to the anchorage of an equivalent non-impact assembly.

13.6 An impact rating belongs to the tested assembly as a whole — that framing, that retention, that glazing makeup, that anchorage. Substituting any one of them voids the rating, and the substitution shall not be made without a test report covering the assembly as substituted.

NOTE The rating is a system property because the failure mode is a system failure: the missile cracks the laminated lite, and everything that follows depends on whether the interlayer stays bonded and the frame keeps holding the cracked lite while the wind cycles it thousands of times. Glass that survives the impact still fails the test if the frame lets go. (13.7)

14 Perimeter Fire Containment at the Floor Edge

14.1 A perimeter fire containment system shall be installed in the void between the back of the curtain wall and the edge of the floor slab where the datasheet requires one.

Perimeter Fire Containment Systemradio

○ Required

○ Not required

Derived — the fire-resistance rating of the floor assembly at the slab edge (by default)

14.2 The perimeter fire containment system shall be a system tested per ASTM E2307 and listed for the ratings indicated in the datasheet, installed exactly as the listing describes.

Perimeter Fire Containment F-Ratingrange

hours

1234

Derived — the fire-resistance rating of the floor assembly at the slab edge (by default)

14.3 The listing shall cover the curtain wall framing, the spandrel infill, the back-pan, and the insulation as actually furnished, and a listing for a different wall construction shall not be substituted.

14.4 The building thermal insulation shall not be used to fill the floor edge void unless that insulation is a component of the tested and listed containment assembly.

14.5 The curtain wall contractor and the installer of the containment system shall be present together at the first floor edge condition installed, and that condition shall be inspected and accepted before the work is repeated.

NOTE The floor edge void is the one place in a rated building where a continuous vertical gap runs from floor to floor immediately behind a wall that will fail early in a fire. The containment system closes that gap for the rated period, and it is tested with a curtain wall in front of it precisely because the wall's behavior — glass falling out, aluminum melting, the spandrel opening — is part of what the system has to survive. (14.6)

15 NFPA 285 Assembly Compliance

15.1 The exterior wall assembly shall comply with NFPA 285 where the datasheet requires that compliance.

NFPA 285 Assembly Complianceradio

○ Required

○ Not required

Derived — the building construction type and height, and the presence of foam plastic or other combustible components in the spandrel and back-up assembly (by default)

15.2 Compliance shall be demonstrated by a listing or an engineering evaluation covering the assembly as furnished, including the spandrel glazing, the back-pan, the insulation, the perimeter fire containment, the water-resistive barrier, and every combustible component within the assembly.

15.3 No component within the assembly shall be substituted after the listing or evaluation is accepted unless a revised listing or evaluation covering the substitution is submitted and accepted.

NOTE NFPA 285 tests whether a fire venting out of a window can run up the outside of the building inside the wall assembly. A curtain wall spandrel is a common place for that to happen, because the cavity behind opacified glass is a natural chimney and it is frequently filled with foam plastic insulation. The test evaluates the whole stack-up rather than any single material, which is why a compliant assembly is defined by its listing rather than by the flame-spread rating of its parts. (15.4)

16 Curtain Wall Assembly Method

16.1 The curtain wall shall be assembled by the method indicated in the datasheet.

Curtain Wall Assembly Methodselect

Stick-built, field-assembled from loose members and field-glazed

Semi-unitized, shop-assembled ladder frames erected and field-glazed

Unitized, shop-assembled and shop-glazed panels interlocked in the field

Unitized typical bays with stick-built framing at special conditions

16.2 The assembly method indicated in the datasheet shall not be changed after the shop drawings are reviewed unless the Engineer of Record accepts the change in writing.

16.3 Where any portion of the wall is field-glazed, the Contractor shall provide weather protection over the glazing pocket sufficient to keep it clean and dry until the lite is set.

NOTE A stick-built wall arrives as loose extrusions, anchors, gaskets, and glass, and is assembled and glazed in place. It costs less in material, tolerates irregular geometry and late dimensional change, and needs no crane, but it puts glazing, sealing, and quality control on the building at height, in weather, where the work is slower to perform and harder to inspect. (16.4)

NOTE A unitized wall is fabricated, glazed, sealed, and cured in the shop, then lifted and interlocked at split mullions and stack joints. It costs more per square foot and demands tight dimensional control of the structure and crane access to every elevation, but it erects several times faster, produces more consistent air and water performance because the seals are made under controlled conditions, and takes structural glazing off the building entirely. (16.5)

NOTE A semi-unitized wall splits the difference: shop-assembled framing ladders are hung on the building and glazed in the field, which recovers some of the shop assembly benefit without shipping and craning glazed panels. (16.6)

NOTE The choice tracks the constraints of the specific building far more than the size of the project. Repetitive elevations, high floor counts, an aggressive erection schedule, and limited access for field work push toward unitized construction; irregular geometry, late design change, restricted crane access, and small total area push toward stick construction. (16.7)

17 Water Management Principle

17.1 The curtain wall shall manage water by the principle indicated in the datasheet.

Water Management Principleselect

Pressure-equalized rain screen with a vented and compartmented glazing pocket

Internally drained and back-drained without pressure equalization

Face-sealed barrier wall relying on a single continuous exterior seal

17.2 The glazing pocket and every framing cavity shall drain to the exterior at each horizontal, and the drainage path shall be continuous from the point where water can enter to the point where it discharges.

17.3 Weep and vent openings shall be sized, located, and protected as the tested system requires, and shall discharge clear of the wall face below.

17.4 Weep and vent openings shall not be obstructed by gaskets, setting blocks, sealant, insulation, or the perimeter seal.

17.5 Where the pressure-equalized principle is specified, the cavity shall be compartmented at corners, at parapets, and at the vertical spacing the tested system requires, so that a single cavity cannot bridge two zones of differing exterior pressure.

NOTE The three principles differ in how many lines of defense the wall has. A face-sealed wall stops all water at one continuous exterior seal, so any breach in that line admits water with nothing behind it. An internally drained wall accepts that the outer line leaks, catches what passes on internal gutters, and drains it back out. A pressure-equalized rain screen adds one more step: it vents the cavity to the exterior so cavity pressure rises to match the wind pressure on the outer face, which removes the pressure difference that drives water inward through the outer joints in the first place. (17.6)

NOTE Pressure equalization only works if the vented cavity is compartmented. An uncompartmented cavity running past a building corner connects a zone of high positive pressure to a zone of suction, and the cavity then carries water sideways under the very pressure difference the venting was meant to eliminate. (17.7)

NOTE The venting that equalizes pressure is also the drainage path and also a potential air leakage path, which is why the air control layer sits at the interior of a drained wall and the exterior screen is asked only to shed bulk water. (17.8)

18 Glazing Retention Method

18.1 The glazing infill shall be retained by the method indicated in the datasheet.

Glazing Retention Methodselect

Mechanically captured on all four edges by a pressure plate and cover

Two-side structural silicone glazing with the vertical edges bonded and the horizontal edges captured

Two-side structural silicone glazing with the horizontal edges bonded and the vertical edges captured

Four-side structural silicone glazing

Four-side structural silicone glazing with mechanical toggle retention

18.2 Requirements in this section for structural silicone glazing apply where a structural silicone retention method is selected in the datasheet.

18.3 Where structural silicone glazing is selected, the structural sealant shall conform to ASTM C1184 and the structural joint shall be designed in accordance with ASTM C1401 and AAMA CW-13.

18.4 Where structural silicone glazing is selected, the structural sealant shall be of the type indicated in the datasheet.

Structural Silicone Sealant Typeselect

Not applicable to a mechanically captured system

One-part structural silicone conforming to ASTM C1184

Two-part structural silicone conforming to ASTM C1184

18.5 Where structural silicone glazing is selected, the structural sealant shall be applied at the location indicated in the datasheet.

Structural Silicone Application Locationselect

Not applicable to a mechanically captured system

Shop applied and shop cured under the quality control program

Field applied under the sealant manufacturer's written field quality program

18.6 Where structural silicone glazing is selected, the structural bite and the glue-line thickness shall be sized by the delegated engineer for the design wind pressure and, on any edge that carries glass weight, for the dead load as well.

18.7 Where structural silicone glazing is selected, no organic sealant, tape, gasket, setting block, or spacer shall contact the structural bead unless that material has passed the compatibility program in this standard.

NOTE A captured system holds the lite on all four edges between an exterior pressure plate and a gasket bearing on the inner face, with a snap-on cover concealing the plate. The retention is mechanical, the gasket compression is visible and measurable, and a failed seal leaks rather than releases the glass. (18.8)

NOTE A structurally glazed system bonds the glass to the frame with silicone that carries the wind load into the framing without a mechanical capture on the bonded edges. Two-side glazing bonds one pair of edges and captures the other; four-side glazing bonds all four and produces a flush exterior with no pressure plate interrupting the glass. A toggle system adds a mechanical retention device engaging a channel in the structural bead, which restores a secondary load path on the bonded edges. (18.9)

NOTE Structural glazing is chosen for the flush exterior it produces and for the reduction in thermal bridging and water collection that removing the exterior pressure plate brings. What it costs is the load path: the sealant becomes the only thing holding the glass on the building, which is why the conformance, design, compatibility, application, and cure requirements around it are written as hard obligations rather than as recommendations. (18.10)

19 Framing Member Sizing and Sightline

19.1 The exterior face width of the framing members shall be as indicated in the datasheet.

Mullion Face Width at the Exterior Sightlinerange

in

1.7522.533.5456

Per drawings — as indicated on the exterior elevations and curtain wall details (deferred by default)

19.2 The mullion depth shall be as indicated in the datasheet.

Mullion Depthrange

in

2.534567.5910.5121416

Derived — the clear span between anchors, the governing design wind pressure, and the specified deflection limit (by default)

19.3 Mullion reinforcement shall be as indicated in the datasheet.

Mullion Reinforcementselect

None, extruded aluminum section alone

Internal aluminum reinforcing insert

Internal steel tube reinforcement

Structural steel mullion behind an aluminum cover

Derived — the clear span between anchors, the governing design wind pressure, and the specified deflection limit (by default)

19.4 The mullion depth and reinforcement shall be confirmed against the manufacturer's published span capacities for the actual clear span and the actual design pressure, including the corner and edge zone pressures where the member falls within those zones.

NOTE Once the depth needed exceeds what is available in the system's profiles, the remaining options are to reinforce the existing mullion with an internal insert, to reduce the span by adding an anchor, or to move to a deeper system. Steel reinforcement adds stiffness in the depth already available, at the cost of weight, galvanic isolation, and a longer thermal path through the member. (19.6)

20 Aluminum Extrusions

20.1 Framing extrusions shall conform to ASTM B221.

20.2 Aluminum sheet used for covers, back-pans, and closures shall conform to ASTM B209.

20.3 Primary structural framing members shall be of the alloy and temper indicated in the datasheet.

Structural Framing Alloy and Temperselect

Alloy 6063-T6

Alloy 6063-T5

Alloy 6005A-T61

Alloy 6061-T6

20.4 Pressure plates, covers, and trim shall be of the alloy and temper indicated in the datasheet.

Pressure Plate, Cover, and Trim Alloy and Temperselect

Alloy 6063-T5

Alloy 6063-T6

Alloy 6463-T5

Alloy 6005A-T61

20.5 The wall thickness of primary structural framing members shall be not less than the thickness indicated in the datasheet.

Minimum Wall Thickness of Primary Structural Framing Membersrange

in

0.0620.070.0780.090.10.1250.1560.188

20.6 The wall thickness of non-structural covers and trim shall be not less than the thickness indicated in the datasheet.

Minimum Wall Thickness of Non-Structural Covers and Trimrange

in

0.050.0620.070.0780.09

20.7 Exposed extrusions shall be free of die lines, scratches, dents, and other surface defects visible from a distance of 10 ft under the finished lighting condition, and the Engineer of Record shall make the initial determination where the parties disagree whether a defect is visible.

NOTE The 6063 alloys extrude to fine detail and take an even anodic film, which is why they dominate architectural framing. The higher-strength alloys buy section capacity at the cost of extrudability and of anodizing color consistency, so they appear where a member is working hard rather than across a whole system. Temper matters for the same reason the alloy does: a cover that only has to stay flat can be a softer temper than a mullion carrying wind to an anchor. (20.8)

21 Thermal Barrier

21.1 Framing members shall incorporate a continuous thermal barrier separating the interior aluminum from the exterior aluminum, unless the datasheet specifies non-thermally-broken framing.

21.2 The thermal barrier shall be of the type indicated in the datasheet.

Thermal Barrier Typeselect

Pultruded glass-fiber-reinforced polyamide struts mechanically crimped into the profiles

Poured and debridged polyurethane

Non-thermally-broken framing

21.3 The thermal barrier shall be continuous around every glazing pocket, at every framing intersection, and through every splice, and shall not be interrupted by a fastener, an anchor, a reinforcement, or a drainage opening that bridges the interior and exterior aluminum.

21.4 The barrier shall transfer the shear the delegated engineer's design assigns to it, and where the design treats the profile as acting compositely the barrier shall be qualified for that shear transfer by test.

NOTE A polyamide strut is a structural member in its own right: it is crimped mechanically into knurled channels in both halves of the profile and carries shear between them, which lets the composite section be counted on structurally and permits the interior and exterior halves to carry different finishes. A poured and debridged barrier is formed by filling a cavity in the extrusion with polyurethane and then machining out the metal bridge beneath it, which is simpler to produce and gives a shallower thermal path. (21.5)

NOTE The barrier is only as good as its continuity. A single steel fastener or an unbroken reinforcing insert crossing from inside to outside re-establishes the metal path the barrier was installed to break, and it does so locally at exactly the point where the interior surface is coldest. (21.6)

22 Steel Reinforcement, Fasteners, and Dissimilar Metals

22.1 Steel reinforcement placed within a framing cavity shall be hot-dip galvanized per ASTM A123 or otherwise protected against corrosion for the design life of the wall.

22.2 Fasteners and anchors, whether exposed or concealed, shall be stainless steel or another corrosion-resistant material compatible with both the aluminum and the steel they connect.

22.3 Aluminum shall be isolated from steel, from concrete, and from masonry by a non-conductive separator, a coating, or a gasket at every point of contact.

22.4 Fasteners shall not penetrate the thermal barrier, and shall not bridge the interior and exterior aluminum of a thermally broken member.

22.5 Exposed fasteners shall be finished to match the member they penetrate.

NOTE Aluminum in contact with a more noble metal in the presence of moisture corrodes preferentially, and a curtain wall is wet at every joint by design. The separation requirement is not cosmetic — a corroding aluminum interface at an anchor loses the section it was designed with, in the one place on the wall where losing it matters most. (22.6)

23 Glazing Gaskets and Framing Joint Seals

23.1 Glazing gaskets shall be extruded from the material indicated in the datasheet.

Glazing Gasket Materialselect

EPDM

Silicone

Thermoplastic elastomer

Neoprene

23.2 Gaskets in contact with a structural silicone bead shall be silicone, regardless of the material indicated in the datasheet for gaskets elsewhere in the system.

23.3 Gaskets shall bear continuously against both glass faces at every captured edge, at the compression the tested system requires.

23.4 Gaskets shall be installed in continuous lengths, and corners shall be formed with vulcanized or molded corner pieces, or shall be cut and sealed by the method the system manufacturer publishes.

23.5 Splices in a gasket shall be located away from corners and shall be sealed.

23.6 Framing joints within the fabricated assembly shall be sealed against air and water in the manner the tested system requires, and the sealant used shall be compatible with the gaskets, the finish, and any structural sealant it contacts.

NOTE A discontinuity where a gasket turns a corner is the single most common leak found on a curtain wall mockup, and it is entirely avoidable. The gasket is under compression along its length, so a butt cut at a corner opens under thermal movement even when it looks tight the day it is installed. (23.7)

24 Aluminum Finishes

24.1 Exposed exterior aluminum shall receive the finish indicated in the datasheet.

Exterior Exposed Aluminum Finishselect

Fluoropolymer organic coating conforming to AAMA 2605

Fluoropolymer organic coating conforming to AAMA 2604

Organic coating conforming to AAMA 2603

Powder coating conforming to AAMA 2604

Class I architectural anodic coating conforming to AAMA 611

Class II architectural anodic coating conforming to AAMA 611

Mill finish, uncoated and unanodized

24.2 Exposed interior aluminum shall receive the finish indicated in the datasheet.

Interior Exposed Aluminum Finishselect

Matching the exterior finish

Fluoropolymer organic coating conforming to AAMA 2605

Fluoropolymer organic coating conforming to AAMA 2604

Organic coating conforming to AAMA 2603

Powder coating conforming to AAMA 2604

Class I architectural anodic coating conforming to AAMA 611

Class II architectural anodic coating conforming to AAMA 611

Mill finish, uncoated and unanodized

24.3 The finish color shall be as indicated in the datasheet.

Framing Finish Colortext

Enter value...

Per drawings — as indicated on the exterior elevations and the finish schedule (deferred by default)

24.4 The finish shall be applied to the extrusion before fabrication cuts are made, or the cut ends shall be finished after cutting, so that no unfinished aluminum is exposed in the completed work.

24.5 Anodized members shall be produced from extrusions of a single alloy and, wherever the quantity permits, from a single production lot, so that color variation across an elevation stays within the range shown by the accepted samples.

24.6 Where the color of an anodized member falls outside the range shown by the accepted samples, the member shall be rejected and replaced at the Contractor's cost.

NOTE Organic coating and anodizing fail in different ways and are inspected differently. An organic coating is a film applied over the metal, and its performance classes are graduated by how long the film holds color, gloss, and adhesion under weathering — the higher classes carry longer chalk and fade limits and correspondingly longer warranties. An anodic coating is grown from the metal itself, so it cannot peel, and it is graded by film thickness; its color comes from the alloy and the process, which is why lot-to-lot variation is a real risk on anodized work and a non-issue on coated work. (24.7)

NOTE Where a facade is tall enough or prominent enough that refinishing in place would be impractical, the length of the finish's service life becomes a durability decision rather than a cost decision, because the realistic alternative to a long-lived finish is replacement rather than recoating. (24.8)

25 Vision Glazing Infill

25.1 The vision glazing unit shall be of the configuration indicated in the datasheet.

Vision Glazing Unit Configurationselect

Monolithic glass

Laminated monolithic glass

Double-glazed insulating glass unit

Triple-glazed insulating glass unit

25.2 Laminated lites within the glazing unit shall be positioned as indicated in the datasheet.

Laminated Lite Position in the Glazing Unitselect

No laminated lite

Outboard lite laminated

Inboard lite laminated

Both outboard and inboard lites laminated

25.3 Laminated glass shall conform to ASTM C1172 and shall use the interlayer indicated in the datasheet.

Laminated Glass Interlayerselect

Not applicable to an unlaminated makeup

Polyvinyl butyral

Acoustic-grade polyvinyl butyral

Ionoplast

Ethylene-vinyl acetate

Cast-in-place resin

25.4 Vision glass shall be heat treated as indicated in the datasheet, and heat-treated glass shall conform to ASTM C1048.

Vision Glass Heat Treatmentselect

Annealed

Heat-strengthened

Fully tempered

Fully tempered and heat-soak tested

Derived — the ASTM E1300 load resistance analysis for the lite size and design wind pressure, together with the thermal stress analysis for the specified coating, tint, and shading condition (by default)

25.5 Glazing in a location the adopted building code identifies as a hazardous location shall be safety glazing complying with 16 CFR Part 1201 and ANSI Z97.1.

25.6 Float glass shall conform to ASTM C1036 and shall be of the substrate indicated in the datasheet.

Vision Glass Substrateselect

Clear float glass

Low-iron float glass

Green tinted float glass

Blue-green tinted float glass

Blue tinted float glass

Gray tinted float glass

Bronze tinted float glass

25.7 The low-emissivity coating shall be applied to the surface indicated in the datasheet.

Low-Emissivity Coating Positionselect

No low-emissivity coating

Surface 2

Surface 3

Surface 2 and surface 4

Surface 4

25.8 A sputtered low-emissivity coating shall be edge-deleted at every bonded edge of the unit, back to sound glass, before the edge seal or any structural sealant is applied.

25.9 The insulating glass unit cavity shall be filled with the gas indicated in the datasheet.

Insulating Glass Unit Cavity Gas Fillselect

Air

Argon

Krypton

Argon and krypton mixture

25.10 The insulating glass unit shall use the edge spacer indicated in the datasheet.

Insulating Glass Unit Edge Spacerselect

Aluminum box spacer

Stainless steel box spacer

Thermally improved composite spacer

Thermoplastic spacer with an integral metal vapor barrier

Silicone foam spacer

25.11 Insulating glass units shall be certified to ASTM E2190 and evaluated by the durability test sequence of ASTM E2188.

25.12 Each lite shall be sized and set with the edge clearance, face clearance, and bite the framing system and the glazing design require for the unit thickness and weight actually furnished.

25.13 Setting blocks shall be positioned at the quarter points of the sill, or at the positions the glass fabricator directs for the lite size, and shall not obstruct the drainage path.

25.14 The insulating glass unit thickness, weight, and edge construction shall be reconciled against the glazing pocket, the setting blocks, the gasket compression, and the structural bite before the framing is released for fabrication.

NOTE The coating surface number is counted from the exterior: surface 1 faces the weather, surface 2 faces the cavity from the outboard lite, and so on inward. A solar-control coating placed on surface 2 rejects heat before it enters the cavity, which is what makes it effective against cooling load; a coating on surface 3 does more for winter heat retention. A second low-emissivity coating on surface 4, the interior face, raises the interior glass surface temperature but is exposed to cleaning and handling. (25.15)

NOTE The cavity gas, the spacer, and the coating act on the same number. Argon and krypton conduct less heat than air, a thermally improved spacer stops the metal short-circuit around the cavity edge, and a low-emissivity coating suppresses radiant transfer across the cavity. The spacer's contribution shows up most strongly at the glass edge, which is where interior condensation forms first and where a condensation resistance factor is won or lost. (25.16)

NOTE Heat treatment is not a free upgrade. Heat-strengthened glass roughly doubles the strength of annealed glass and breaks into large fragments that tend to stay in the opening. Fully tempered glass is stronger still and is required where the code calls for safety glazing, but it dices on breakage and carries a small population of nickel sulfide inclusions that can cause spontaneous breakage years after installation. Heat soaking destroys most of those inclusions before the glass leaves the factory, which is what makes it worth its cost where a falling lite is the governing risk. (25.17)

26 Spandrel and Opaque Infill

26.1 Spandrel and opaque areas shall be infilled with the material indicated in the datasheet.

Spandrel Infill Typeselect

Ceramic-frit opacified spandrel glass over an insulated back-pan

Opacifier-film spandrel glass over an insulated back-pan

Shadow box with vision glass over a finished back-pan

Opaque insulated metal panel

Stone or composite panel infill

No spandrel or opaque areas in this curtain wall

26.2 The back-pan shall be fabricated from the material indicated in the datasheet.

Spandrel Back-Pan Materialselect

Galvanized steel

Aluminum

Stainless steel

No back-pan required by the specified infill type

26.3 Spandrel glass shall be heat-strengthened as a minimum.

26.4 The back-pan shall be sealed to the framing continuously so that it forms part of the air control layer, and its joints and penetrations shall be sealed with materials compatible with the framing finish.

26.5 The spandrel cavity shall be drained and vented to the exterior on the same principle as the vision glazing pocket, unless the tested system is qualified for a sealed spandrel cavity.

26.6 The insulation, the back-pan, and the air seal at the spandrel shall be positioned so that the thermal and air control layers of the curtain wall meet the corresponding layers of the back-up construction without a gap, coordinated with Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation and Air BarriersAir BarriersResolves to the current edition.sync/air-barriers.

26.7 Where the spandrel assembly contains foam plastic or another combustible component, the assembly shall be the one covered by the NFPA 285 listing required by this standard.

NOTE A spandrel cavity behind opacified glass runs far hotter than any other part of the wall, because the glass absorbs solar energy and the opaque backing stops it from passing through. That heat is why spandrel glass is heat treated, why the frit or opacifier has to be a durable ceramic rather than a paint, and why insulation held tight against the back of the glass causes breakage. (26.8)

NOTE A shadow box substitutes a visible depth of finished cavity for an opacified lite, so the viewer sees through clear or coated glass into a dark recess. It gives a more consistent appearance with adjacent vision glass, and it makes the cavity's ventilation, dust control, and condensation behavior visible to anyone standing outside — which is why a shadow box is detailed with more care about cavity venting and interior finish quality than an opacified spandrel needs. (26.9)

27 Anchorage to the Building Structure

27.1 The curtain wall shall be anchored to the building structure at every floor by the anchor type indicated in the datasheet.

Anchor Type at the Building Structureselect

Slab-edge embedded plate with a welded or bolted clip

Cast-in serrated channel with an adjustable bolted connection

Face-of-slab post-installed anchor

Through-slab bolted anchor

Spandrel beam or edge angle with a bolted or welded clip

Per drawings — as indicated on the anchorage details (deferred by default)

27.2 Each anchor shall transfer the wind load acting inward and outward, and the dead weight of the wall it supports, into the building structure.

27.3 Anchors shall be adjustable in three orthogonal directions through a range sized for the erection tolerances of the supporting structure, so that the framing can be set plumb, level, and in plane without forcing a member.

27.4 The dead weight of each segment of the wall shall bear at one defined point, and every other anchor supporting that segment shall be free to move vertically.

27.5 Anchor design, embedment or attachment, and the load path into the structure shall be performed by the delegated engineer and shall be reviewed by the building structural engineer of record before fabrication.

27.6 Where the as-built structure exceeds the erection tolerance the anchor was designed to absorb, the Contractor shall report the condition in writing and shall not modify an anchor, add a shim stack outside the reviewed detail, or field-weld a connection until the delegated engineer has accepted the remedy in writing.

27.7 Welds made in the field shall be cleaned and coated with a corrosion-protective coating, and the isolation between dissimilar metals shall be restored after welding.

NOTE The anchor is where two trades' tolerances meet, and they are not the same size. A concrete or steel frame is erected to tolerances measured in fractions of an inch per floor and can accumulate more than an inch of deviation over a facade; the curtain wall is fabricated to tolerances measured in sixteenths. Three-way adjustability at the anchor is what converts one into the other, and it is consumed at erection, not held in reserve. (27.8)

28 Movement Accommodation

28.1 Vertical movement between stacked segments of the wall shall be taken at the joint type indicated in the datasheet.

Vertical Movement Joint Typeselect

Telescoping stack joint between vertically stacked units

Slotted expansion horizontal member

Expansion splice within the vertical mullion

Sliding anchor connection above a fixed dead-load anchor

Derived — the curtain wall assembly method and the design vertical movement at the floor edge (by default)

28.2 Movement joints shall accommodate the live-load and creep deflection of the supporting floor edges, the differential vertical movement between floors, the thermal movement of the framing over the design temperature changes, and the design interstory drift, acting in combination.

28.3 The movement range designed into each joint and each anchor slot shall remain free after erection, and shall not be consumed by shims, by sealant, by fasteners tightened across a slot, or by a field weld.

28.4 Gaskets, sealants, and splice seals at a movement joint shall maintain continuity of the air and water control layers through the full range of movement.

28.5 Anchor slots shall be inspected for free movement after the wall is erected and before the interior finishes conceal them.

NOTE An anchor or a splice inadvertently fixed where it was designed to slide does not announce itself. The wall looks correct, passes a water test, and then transfers building movement directly into the glass the first time the structure deflects or the facade heats unevenly. This is why the free movement of slots is verified as an inspection item rather than assumed from the shop drawings. (28.6)

29 Air and Water Barrier Continuity at the Perimeter

29.1 The interior air seal plane of the curtain wall shall be made continuous with the air barrier of every adjacent assembly, coordinated with Air BarriersAir BarriersResolves to the current edition.sync/air-barriers.

29.2 The transition between the curtain wall air seal and the adjacent air barrier shall be made with a membrane or sealant detailed to accommodate the differential movement between the curtain wall and the adjacent construction without rupture or debonding.

29.3 The transition detail shall be shown on the shop drawings, built in the mockup, and inspected in place before it is concealed.

29.4 The perimeter water seal shall collect any water reaching the perimeter and direct it back to the exterior.

29.5 The base and sill conditions shall receive an end-dammed pan flashing that receives the discharge of the curtain wall drainage system and any perimeter water, and drains it to the exterior clear of the construction below, coordinated with Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current edition.sync/sheet-metal-flashing-and-trim.

29.6 The perimeter joint between the curtain wall frame and the adjacent construction shall be sealed with the sealant type indicated in the datasheet, sized for the calculated joint movement and installed over the correct backing per Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants.

Perimeter Joint Sealant Typeselect

Silicone conforming to ASTM C920 Type S Grade NS Class 100/50

Silicone conforming to ASTM C920 Type S Grade NS Class 50

Silyl-terminated polyether conforming to ASTM C920 Type S Grade NS Class 50

Polyurethane conforming to ASTM C920 Type S Grade NS Class 35

29.7 The sealant manufacturer shall confirm in writing that the selected sealant is compatible with the curtain wall finish and with every adjacent substrate it will contact, and shall confirm whether a primer is required on each.

NOTE The wall itself is tested in a laboratory under controlled conditions; the perimeter is built in the field at the seam between two subcontracts. That asymmetry, rather than any weakness in the systems themselves, is why so many curtain wall leak investigations end at the head, the jamb, or the base rather than at the wall. (29.8)

NOTE A perimeter joint has to be both airtight and capable of movement, and those two demands pull against each other. The joint width, the backing, and the sealant's movement class are one design, not three independent choices, and the movement the joint actually sees comes from the same thermal and structural analysis that sized the wall's own movement joints. (29.9)

30 Fabrication

30.1 Framing shall be fabricated to the dimensions and tolerances of the reviewed shop drawings, with members cut, machined, drilled, and prepared for assembly in the shop.

30.2 Joints within the fabricated assembly shall be sealed against air and water infiltration as the tested system requires.

30.3 Where the wall is unitized or semi-unitized, panels shall be assembled, sealed, and where applicable structurally glazed and cured in a controlled shop environment before shipment.

30.4 Fabrication tolerances shall be held tightly enough that the interlock and the stack joint of adjacent units engage through their full design range at the erection tolerances of the structure.

30.5 Finished surfaces shall receive a strippable coating or a protective covering before the member leaves the shop.

30.6 Aluminum shall be handled, stored, packaged, and shipped in accordance with AAMA CW-10 from the finishing line to the point of installation.

NOTE A unitized wall has no field adjustment inside the panel: the interlock either engages or it does not, and every dimension that governs whether it does was fixed in the shop. This is why shop tolerance control on a unitized wall is a schedule risk rather than a quality preference — a panel that does not fit comes off the building and goes back to the shop. (30.7)

31 Mockups

31.1 Mockups shall be provided as indicated in the datasheet.

Visual Mockupradio

○ Required

○ Not required

Laboratory Performance Mockupradio

○ Required

○ Not required

Field Mockupradio

○ Required

○ Not required

31.2 Where a laboratory performance mockup is required, it shall be subjected to the tests indicated in the datasheet, in the sequence the referenced test methods and AAMA 501 establish.

Laboratory Performance Mockup Test Sequencecheckbox

☐ Air infiltration per ASTM E283

☐ Static water penetration per ASTM E331

☐ Dynamic water penetration per AAMA 501.1

☐ Structural performance at design pressure per ASTM E330

☐ Structural overload at 1.5 times design pressure per ASTM E330

☐ Static interstory drift per AAMA 501.4

☐ Vertical interstory movement per AAMA 501.7

☐ Thermal cycling per AAMA 501.5

☐ Dynamic glass fallout per AAMA 501.6

☐ Missile impact and cyclic pressure per ASTM E1886

31.3 A laboratory performance mockup shall include a typical vision area, a spandrel or opaque area, an intersection of a vertical and a horizontal member, a movement or corner joint, an anchor condition, and the transition to at least one adjacent enclosure assembly.

31.4 A laboratory performance mockup shall be tested as a complete assembly so that the air seal, the drainage system, the anchorage, and the movement provisions are evaluated together rather than individually.

31.5 A visual mockup shall establish color, gloss, finish uniformity, glass appearance, and sightline only, and shall not be used as evidence of air, water, structural, or thermal performance.

31.6 A field mockup shall be erected in the permanent work at a location the Engineer of Record designates, using the same materials, details, crew, and sequence as the production work.

31.7 Deficiencies identified in any mockup shall be corrected and the affected test repeated until the mockup passes, and production fabrication shall not be released until it does.

31.8 The Contractor shall bear the cost of the mockup, of the initial testing, of every correction, and of every re-test following a failure.

31.9 The completed wall shall match the accepted mockup in materials, details, and workmanship.

NOTE A laboratory mockup tests the system; a field mockup tests the crew and the sequence. They fail in different ways, and a project that has reason to doubt either one is the project that benefits from that mockup. The laboratory mockup is also the only opportunity to find a system defect while changing it is still a drawing revision rather than a facade retrofit. (31.10)

32 Installation

32.1 The Contractor shall erect the curtain wall plumb, level, and in plane within the tolerance indicated in the datasheet.

Framing Erection Alignment Toleranceselect

1/8 in. in 12 ft, and 1/4 in. maximum in any total run

1/16 in. in 12 ft, and 1/8 in. maximum in any total run

As established by the reviewed shop drawings and the system manufacturer's published erection tolerances

32.2 Anchors shall be set and adjusted to absorb the as-built deviation of the structure before they are secured.

32.3 Erection shall be sequenced with the adjacent enclosure trades so that the air and water barrier transitions are made as the wall rises rather than retrofitted behind completed work.

32.4 Field glazing shall be performed only after the framing is installed within tolerance, is protected from weather, and has a clean and dry glazing pocket.

32.5 Each lite shall be set centered in its pocket on setting blocks, with the edge clearance, face clearance, and bite the glazing design requires.

32.6 Gaskets shall be installed without stretching, and shall be cut long and eased into place so that they do not shrink back from the corners after installation.

32.7 The drainage and pressure-equalization openings shall be verified clear after glazing and after the perimeter seal is installed.

32.8 Field welding, cutting, and grinding shall not be performed within reach of installed glass or finished aluminum unless sacrificial protection is in place.

32.9 Damage to the finish, the glass, or a coating caused by field welding, cutting, or grinding shall be repaired by replacement of the damaged component at the Contractor's cost.

NOTE A gasket installed under tension is the most common self-inflicted leak on a field-glazed wall. Extruded elastomer stretched during installation recovers over the following weeks and pulls back from the corners, opening exactly the discontinuity the corner detail exists to prevent. (32.10)

NOTE A blocked weep is invisible from either face and defeats the entire drainage design. Water held in the glazing pocket sits against the insulating glass unit edge seal, which is the condition that leads to premature seal failure and fogging years after the wall was accepted. (32.11)

33 Field Quality Control

33.1 Field water penetration testing of the installed wall shall be performed by the methods indicated in the datasheet.

Field Chamber Water Test per AAMA 503 and ASTM E1105radio

○ Required

○ Not required

Diagnostic Spray Water Check per AAMA 501.2radio

○ Required

○ Not required

Field Air Leakage Test per ASTM E783radio

○ Required

○ Not required

33.2 The field chamber water test shall be performed at the pressure indicated in the datasheet.

Field Water Test Pressurerange

psf

456.24810121520

Derived — two-thirds of the static water penetration test pressure specified for the laboratory test (by default)

33.3 Field testing shall be performed at the frequency indicated in the datasheet, distributed across elevations, heights, and conditions rather than concentrated in one area.

Field Water Test Frequencyrange

ft² of wall per test

250050007500100001500020000

33.4 The first field test shall be performed on the first representative area completed, so that any systemic defect is found before the detail is repeated across the facade.

33.5 Leakage found in field testing shall be located, corrected, and re-tested at the same location and at one additional location of the Engineer of Record's choosing.

33.6 The Contractor shall bear the cost of correcting a failure and of every re-test following a failure, and the Owner shall bear the cost of tests that pass beyond the frequency indicated in the datasheet.

33.7 Testing shall be performed by an independent agency engaged by the Contractor and shall be witnessed by the Engineer of Record or the Engineer's designated representative.

NOTE The chamber test and the spray check answer different questions. A calibrated chamber applies a known pressure difference across a known area and produces a pass or fail against a stated criterion, which is what a certified field performance result requires. A diagnostic spray check applies water to a small area without a chamber and is used to walk a leak back to its source. The second finds the defect; only the first proves the wall. (33.8)

NOTE Field pressure is set below the laboratory pressure because the installed wall is being asked to demonstrate the performance it was built to, not to repeat a qualification test the system already passed under controlled conditions with a specimen frame sealed into a chamber. (33.9)

34 Delivery, Storage, and Handling

34.1 Materials shall be delivered in the manufacturer's original packaging with the protective covering intact and with each item identified by the mark shown on the reviewed shop drawings.

34.2 Framing and glazing shall be stored off the ground, under cover, sloped to drain, and separated by non-staining spacers that allow air to circulate between stacked members and lites.

34.3 Aluminum shall not be stored in contact with mortar, plaster, concrete, or any alkaline material, and shall not be stored where runoff from those materials can reach it.

34.4 Glass shall be stored upright on padded supports and shall not be stored where the lites can trap water between them.

34.5 The strippable coating or protective covering shall remain in place until the surrounding work that could damage the finish is complete.

34.6 Damaged or contaminated materials shall be removed from the site and replaced at the Contractor's cost.

NOTE Water trapped between stacked lites in storage etches the glass surface permanently, and the damage is not visible until the lite is cleaned and set. Alkaline runoff does the same to an anodic film. Both are storage failures that surface as appearance rejections after installation, when correcting them means replacement. (34.7)

35 Cleaning and Protection

35.1 Finished aluminum and glass shall be protected from construction operations and from construction contaminants from delivery through substantial completion.

35.2 At substantial completion the aluminum and the glass shall be cleaned with clean water and a mild detergent applied with soft cloths or sponges.

35.3 Abrasive pads, blades, scrapers, powered cleaning equipment, and acidic or alkaline cleaning agents shall not contact the framing finish, the glass, the glass coatings, or the insulating glass unit edge seals.

35.4 Where a construction residue cannot be removed by the permitted cleaning method, the Contractor shall obtain the written cleaning procedure of the finish or glass manufacturer whose product is affected before attempting any other method.

35.5 Weep and vent openings shall be verified clear of cleaning residue after final cleaning is complete.

35.6 Cleaning agents and methods that would void the finish warranty or the glass coating warranty shall not be used, and the Contractor shall bear the cost of replacing any component whose warranty is voided by the cleaning method used.

36 Warranty

36.1 The Contractor shall warrant the curtain wall system against defects in materials and workmanship, including air infiltration and water penetration in excess of the performance specified, for the term indicated in the datasheet, beginning at substantial completion.

System Workmanship Warranty Termrange

years

123510

36.2 The exterior finish shall be warranted against loss of adhesion, chalking, fading, and film failure for the term indicated in the datasheet.

Exterior Finish Warranty Termrange

years

510152030

Derived — the exterior finish system specified and the term the coating or anodizing applicator publishes for that system (by default)

36.3 Insulating glass units shall be warranted against seal failure, obstruction of vision by internal moisture, and internal dust accumulation for the term indicated in the datasheet.

Insulating Glass Unit Warranty Termrange

years

5101520

36.4 Where structural silicone glazing is used, the structural sealant shall be warranted against adhesive and cohesive failure for the term indicated in the datasheet.

Structural Silicone Glazing Warranty Termrange

years

51020

36.5 Warranties shall be written in the name of the Owner and shall remain transferable for the full term.

36.6 Work repaired or replaced under any of these warranties shall carry a new warranty for the full original term running from the date of the repair, or for the remainder of the original term, whichever ends later.

36.7 The party performing a warranty repair shall bear the cost of access to the work, of removing and reinstalling adjacent construction disturbed by the repair, and of repairing damage to the building and its contents caused by the defect or by the repair itself.

NOTE A warranty repair on a facade is rarely limited to the defective component: reaching it can require swing stage access, removal of interior finishes, or de-glazing adjacent lites. Leaving those costs unassigned turns a covered repair into a dispute about who pays to get to it, which is why they are assigned here rather than left to the warranty certificate. (36.8)

37 Extra Stock Materials

37.1 The Contractor shall deliver to the Owner the quantity of replacement glazing units indicated in the datasheet, of each vision and spandrel makeup used on the project.

Extra Stock Glazing Unitsrange

units

12461020

37.2 The Contractor shall deliver to the Owner the length of each glazing gasket profile used on the project indicated in the datasheet.

Extra Stock Glazing Gasket Lengthrange

ft

50100200500

37.3 Extra stock materials shall be from the same production lot as the installed work, shall be labeled with the mark and the makeup they replace, and shall be stored where the Owner directs.

37.4 Extra stock glazing units shall be delivered with the setting blocks, gaskets, and fasteners a single lite replacement consumes.

NOTE A curtain wall lite is the hardest component on a building to obtain quickly after the project closes. Coating runs change, tint lots shift, and a fabricator can drop the makeup entirely, so a broken lite years later becomes a visible mismatch across a whole elevation. Attic stock bought from the original run is the only way to keep a later replacement invisible. (37.5)