1 Scope

NOTE This standard covers the materials, design basis, fabrication, attachment, sealing, and testing of exterior metal wall panel systems that form the visible cladding of the above-grade wall enclosure. The work includes: (1.1)

The metal panels themselves, and the panel cores and factory insulation where present
The coil and panel finishes
The sub-girts, hat channels, clips, and other attachment and support components that carry the panel back to the structure or sheathing
The panel joints, gaskets, and sealants
The perimeter and penetration closures and the interface trim that ties the panel system to flashings, openings, and the air and water control layers behind it
The laboratory and field verification that the installed wall meets its air, water, structural, thermal, and fire performance requirements

NOTE A metal wall panel is not, by itself, a complete wall. It is one layer of a multi-layer assembly whose other layers — the air barrier, the water-resistive barrier, the continuous insulation, and the structural backup — perform functions the panel does not; the panel's job is to shed the bulk of the weather, resist wind load, and present the architectural face. The most consequential idea in this standard is therefore that the panel and the layers behind it are designed and sequenced together: a perfectly fabricated panel installed over a discontinuous air barrier, or without a drainage path behind it, produces a wall that leaks air, traps water, and rots regardless of the panel's own quality. (1.2)

NOTE The way a metal panel wall manages water is the defining distinction among system types. A face-sealed (barrier) wall relies on the panel face and its sealed joints as the sole line of water defense, and it fails the moment any joint sealant fails. A drained-and-back-ventilated or pressure-equalized rainscreen, by contrast, accepts that some water will get past the outer face and provides a drained, ventilated cavity behind the panel and a continuous water-resistive barrier on the back-up wall that is the true water line of defense. Rainscreen construction is forgiving of the inevitable imperfection in field-applied joints, which is why it dominates modern commercial practice; the chosen water-management strategy governs nearly every other decision in this standard and is fixed first. (1.3)

NOTE The boundary of work under this standard is the metal panel cladding system and its attachment, from the face of the panel back to and including the clips, sub-girts, and fasteners that engage the structure or the sheathing. Adjacent work is covered as follows: (1.4)

The continuous air barrier and water-resistive barrier on the back-up wall — Air BarriersAir BarriersResolves to the current edition.sync/air-barriers
The wall thermal insulation, including continuous exterior insulation behind open-jointed panels — Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation, except where the insulation is integral to a factory-foamed insulated metal panel, in which case it is part of the panel and is covered here
The architectural sheet metal flashing, coping, and trim that meet the panel — Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current edition.sync/sheet-metal-flashing-and-trim
The perimeter and movement-joint sealants — Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants
The connection of the panel system to each of those adjacent systems — covered here

1.5 All work shall comply with the adopted edition of the International Building Code (IBC), the structural load provisions of ASCE 7, and the panel manufacturer's published engineering and installation requirements.

1.6 The wall shall be designed as a system, and the panel system's interfaces to the air barrier, to the flashings, and to the openings shall be detailed and coordinated before the panel system is selected.

2 Referenced Standards

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

2.2 Where the contract documents, the adopted building or energy code, the panel manufacturer's published instructions, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

Standard	Title
IBC	International Building Code — Chapter 14 (Exterior Walls), Section 1407 (Metal Composite Materials), Section 2603 (Foam Plastic Insulation)
IECC	International Energy Conservation Code
ASHRAE 90.1	Energy Standard for Buildings Except Low-Rise Residential Buildings
ASCE 7	Minimum Design Loads and Associated Criteria for Buildings and Other Structures (components-and-cladding wind pressures)
NFPA 285	Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components
ASTM E84	Standard Test Method for Surface Burning Characteristics of Building Materials
ASTM E119 (UL 263)	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 Across the Specimen
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 E1233	Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights, and Curtain Walls by Cyclic Air Pressure Differential
ASTM E1592	Standard Test Method for Structural Performance of Sheet Metal Roof and Siding Systems by Uniform Static Air Pressure Difference
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 508	Voluntary Test and Classification Method for Pressure Equalized Rain Screen Wall Cladding Systems
AAMA 509	Voluntary Test and Classification Method for Drained and Back Ventilated Rain Screen Wall Cladding Systems
ASTM C518	Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
ASTM C1363	Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus
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
AAMA 611	Voluntary Specification for Anodized Architectural Aluminum
AAMA 621	Voluntary Specification for High Performance Organic Coatings on Coil Coated Architectural Hot Dipped Galvanized (HDG) and Zinc-Aluminum Coated Steel Substrates
ASTM D523	Standard Test Method for Specular Gloss
ASTM D2244	Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
ASTM D4214	Standard Test Methods for Evaluating the Degree of Chalking of Exterior Paint Films
ASTM A240/A240M	Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
ASTM A653/A653M	Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process
ASTM A792/A792M	Standard Specification for Steel Sheet, 55% Aluminum-Zinc Alloy-Coated by the Hot-Dip Process
ASTM B69	Standard Specification for Rolled Zinc
ASTM B209	Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
ASTM B370	Standard Specification for Copper Sheet and Strip for Building Construction

2.3 The panel manufacturer's tested-assembly limits — span, load, and the specific NFPA 285-compliant assembly configuration — shall not be exceeded or altered even where this standard or the drawings would otherwise permit it.

3 Submittals

3.1 Action Submittals

NOTE The panel's fire compliance, structural capacity, and weathertightness all depend on the specific tested assembly configuration and cannot be evaluated product by product, so the package is reviewed as a coordinated whole. (3.1.1)

3.1.2 The Contractor shall submit the following for the Engineer's review and return before procurement and fabrication:

Product data for the panel system, identifying the panel family, the metal substrate and its specification and gauge or thickness, the core or insulation type and thickness, the finish system, the system water-management type, and the attachment method
Shop drawings showing panel layout and module, joint locations and joint type, the complete attachment and support system (clips, sub-girts, hat channels, fasteners) with the load path to the structure, every perimeter and penetration closure, end dams and flashings at openings, expansion and movement joint locations, inside and outside corners, base and parapet terminations, and the relationship of the panel to the air barrier and water-resistive barrier plane behind it
Structural calculations, sealed by a professional engineer where required by the jurisdiction, demonstrating that the panel, its attachments, and the supporting sub-framing resist the components-and-cladding wind pressures within the panel manufacturer's tested span and load limits and within the specified deflection limit
NFPA 285 compliance evidence for combustible-component assemblies — a passing test report for the specific assembly, or an engineering analysis (engineering judgment) prepared by a qualified fire-protection engineer extending a tested assembly to the proposed configuration
Surface-burning (ASTM E84) test data for the panel and core, and for MCM the assembly flame-spread and smoke-developed indices per IBC Section 1407
Finish product data and the finish warranty specimen, showing the AAMA grade and the color change (ASTM D2244), chalk (ASTM D4214), and gloss-retention (ASTM D523) limits and warranty period
Color and finish samples on the actual specified metal substrate, of sufficient size to evaluate color, gloss, and metallic or mica orientation in natural daylight
Air, water, and structural performance test reports for the panel system in the configuration matching the project
Manufacturer's installation instructions and the installer's qualification documentation
A written field water-test (AAMA 501.2) plan where field water testing is required, identifying the joints to be tested, the test method, and the acceptance criteria

Action Submittals Requiredcheckbox

☑ Panel system product data

☐ Shop drawings (layout, joints, attachment, closures, barrier interface)

☐ Structural calculations to ASCE 7 components-and-cladding

☐ NFPA 285 test report or engineering judgment

☐ ASTM E84 surface-burning data

☐ Finish product data and finish warranty specimen

☐ Color and finish samples on actual substrate

☐ Air/water/structural test reports

☐ Manufacturer installation instructions and installer qualifications

☐ AAMA 501.2 field water-test plan (where field testing is required)

3.1.3 The panel system, its attachment, the finish, and the documentation of fire performance shall be submitted together as a coordinated package.

3.1.4 Piecemeal product-by-product submittal shall not be accepted.

3.2 Closeout Submittals

3.2.1 At substantial completion, the Contractor shall provide the following before the panel work is accepted:

Executed finish warranty and, where required, the manufacturer's weathertightness or system warranty
Executed Contractor installation warranty
Field water-test (AAMA 501.2) reports where field testing was performed, recording each joint tested, the result, and the remediation and re-test of any leak
Marked-up as-built shop drawings showing actual joint, expansion-joint, and field-cut conditions
Touch-up finish in each specified color in sealed factory containers, and attic stock where required
Maintenance instructions for cleaning, periodic joint-sealant inspection, and finish care

Closeout Submittals Requiredcheckbox

☑ Executed finish warranty and system warranty (where required)

☐ Executed Contractor installation warranty

☐ AAMA 501.2 field water-test reports (where performed)

☐ Marked-up as-built shop drawings

☐ Touch-up finish and attic stock (where required)

☐ Maintenance instructions

4 Quality Assurance

4.1 Installer Qualifications

NOTE Metal panel work is unforgiving of inexperience precisely where it matters most — at the corners, terminations, and penetration closures, where the watertightness and the fire-compliant continuity of the assembly are won or lost, and which are difficult to inspect after the work is enclosed. (4.1.1)

4.1.2 The panel installer shall meet the qualification basis selected in the datasheet.

Installer Qualification Basisradio

● Manufacturer-trained and approved for the specific panel system

○ Manufacturer-approved, with documented comparable project experience

4.1.3 Where the manufacturer's warranty is conditioned on an approved installer, that condition shall govern regardless of the selected qualification basis.

4.2 Pre-Installation Conference

NOTE The purpose of the conference is to resolve, in advance and on paper, which trade installs each part of every transition and closure, in what sequence, and how responsibility for air and water continuity and for the NFPA 285-compliant configuration is handed off. The overwhelming majority of metal panel wall failures originate at these trade boundaries, not in the panels themselves. (4.2.1)

4.2.2 Before panel work begins, the Contractor shall convene a pre-installation conference with the Engineer, the panel manufacturer's representative, the panel installer, and the installers of every adjacent trade whose work meets the panel system — air barrier, sheet metal flashing, fenestration, and joint sealants.

4.2.3 The conference shall document which trade installs each transition and closure, in what sequence, and how responsibility for air and water continuity and for the NFPA 285-compliant configuration is handed off.

4.3 Mockups

NOTE The mockup exists to expose workmanship and detailing problems at the conditions where walls actually fail — joints, corners, terminations, and penetrations — while they are still cheap to correct, and to fix the standard of workmanship against which the production work is judged. (4.3.1)

4.3.2 The mockup requirement shall be as selected in the datasheet.

Mockup Requirementradio

○ Standalone field mockup

○ In-place mockup (first area of installed work)

○ Not required

4.3.3 Where a mockup is required, it shall incorporate at least one of each critical condition — a typical field joint, an inside and an outside corner, a base or sill termination, a parapet or head termination, and a penetration closure — together with the air barrier and water-resistive barrier behind it and the interface flashings.

4.3.4 The mockup shall be reviewed and accepted by the Engineer and the manufacturer's representative before production panel installation proceeds, and shall establish the standard of workmanship for the project.

4.3.5 Where field water testing is required under this standard, the mockup shall be water-tested per AAMA 501.2 before acceptance.

5 Environmental and Service Conditions

5.1 Design Wind Pressure

NOTE Negative (suction) pressure usually governs metal panel attachment, because the panel and its clips must hold the panel onto the wall against wind trying to pull it off, and a panel pulled off in a storm becomes a projectile. Corner and edge zones see substantially higher suction than the wall field and govern attachment spacing there. (5.1.1)

5.1.2 The panel system, its attachments, and its sub-framing shall resist the positive and negative components-and-cladding wind pressures determined per ASCE 7 for the building's height, exposure, risk category, and the wall zone in question.

Design Wind Pressure, Wall Field (ASCE 7 components-and-cladding)range

psf

20304050607590120

Per drawings — components-and-cladding wind pressure schedule on the structural drawings (deferred by default)

5.1.3 The panel layout and clip or fastener pattern shall reflect the increased suction in the corner and edge zones.

Design Wind Pressure, Corner and Edge Zones (ASCE 7 components-and-cladding)range

psf

3045607590120150200

Per drawings — components-and-cladding wind pressure schedule on the structural drawings (deferred by default)

5.2 Thermal Movement

NOTE Metal panels expand and contract significantly with temperature, and dark-colored panels in direct sun reach far higher surface temperatures — and move more — than light panels. Concealed-fastener systems accommodate movement at clips and floating connections; exposed-fastener systems accommodate it at slotted or oversized fastener holes that let the panel slide relative to the fastener. (5.2.1)

5.2.2 The panel system shall accommodate thermal movement over the design surface temperature range without buckling, oil-canning, fastener pull-through, or joint failure.

Design Surface Temperature Range for Thermal Movementrange

°F

120150180200220

5.2.3 The design temperature range shall account for the panel color and orientation.

5.2.4 The attachment shall fix each panel at one point and allow movement elsewhere, and shall not restrain a panel at two points such that thermal stress has no relief.

5.3 Corrosion Exposure

NOTE Coastal sites, de-icing-salt exposure, and industrial atmospheres are aggressive to metal cladding; in those environments the corrosion resistance of the substrate, the finish grade, and the fastener material each become service-life decisions rather than cost decisions. Galvanic compatibility is a hard constraint everywhere: dissimilar metals in contact, or noble-metal runoff onto a less noble metal below, corrode for the life of the building. (5.3.1)

5.3.2 The metal substrate, finish, and fasteners shall be selected for the corrosion exposure category of the site.

Corrosion Exposure Categoryradio

○ Inland, normal atmospheric

○ Industrial or urban atmosphere

○ Coastal or marine

○ Severe (de-icing salt or chemical exposure)

5.3.3 Where the coastal/marine or severe category applies, fasteners shall be stainless steel Type 316 and the substrate and finish shall be of grades the manufacturer publishes as suitable for that exposure.

5.3.4 Dissimilar metals in contact, and drainage paths that carry runoff from a more noble metal onto a less noble metal, shall be isolated or separated to prevent galvanic corrosion.

5.3.5 Aluminum and zinc-coated or zinc-aluminum-coated steel shall be protected from continuous contact with wet alkaline materials such as fresh concrete and mortar runoff.

6 Assembly Performance

NOTE Air leakage, water penetration, structural resistance, thermal transmittance, and fire propagation are properties of the tested assembly — the panel together with its joints, attachment, and closures — not of the bare panel, and a system that passes in one joint and attachment configuration can fail in another. (6.1)

6.2 Air Leakage

NOTE Air leakage through the cladding wastes energy and, far more damaging, carries interior humidity into the wall where it condenses. The panel system contributes to the wall's air control, but the continuous air barrier on the back-up wall — specified in Air BarriersAir BarriersResolves to the current edition.sync/air-barriers — is the primary air control layer, and the panel air-leakage requirement is in addition to, not a substitute for, that air barrier. (6.2.1)

6.2.2 The panel system shall limit air leakage through the assembly to not more than the specified rate when tested per ASTM E283 at a static pressure difference of 6.24 psf (300 Pa).

Maximum Air Leakage (ASTM E283 at 6.24 psf)range

cfm/ft²

0.020.040.060.12

6.2.3 The panel air-leakage requirement and the continuous air barrier on the back-up wall shall be coordinated so that the assembly air control is continuous.

6.3 Water Penetration

NOTE What "no water penetration" means depends on the water-management strategy. In a face-sealed wall the panel face and its sealed joints must stop all water, and the test pressure is held against that single line of defense. In a drained-and-back-ventilated or pressure-equalized rainscreen, water passing the outer joints is expected and permitted into the drained cavity, provided it drains back out and never reaches the interior past the water-resistive barrier; the test confirms that the back-up water line and the drainage path perform. (6.3.1)

6.3.2 There shall be no uncontrolled water penetration to the interior of the assembly when tested per ASTM E331 and, where dynamic testing is required by the contract documents, per AAMA 501.1, at the specified test pressure.

6.3.3 Unless the datasheet specifies a different pressure, the water penetration test pressure shall be not less than 20% of the positive design wind pressure for the wall field and not less than 6.24 psf.

Water Penetration Test Pressure (ASTM E331 / AAMA 501.1)range

psf

2.866.24810121520

6.4 Structural Performance Under Wind Load

NOTE ASTM E1592 is written for formed sheet metal siding tested as a system of panels, joints, and fasteners, so it applies where the panel is a profiled sheet whose capacity depends on its profile and its engagement at the seams; ASTM E330 is the uniform-static-pressure chamber test used where the panel behaves as a unitized plate or cassette. (6.4.1)

6.4.2 The panel and its attachment shall sustain the design positive and negative wind pressures without permanent deformation, disengagement, or failure when tested per the selected structural test method.

Structural Test Methodradio

○ ASTM E1592

○ ASTM E330

6.4.3 Panel deflection under the design wind pressure shall not exceed the selected limit.

Panel Deflection Limit Under Design Wind Loadradio

○ L/90

● L/120

○ L/180

○ L/240

NOTE Deflection is limited not only to prevent damage but to prevent the visible waviness (oil-canning) and joint-opening that excessive deflection causes; L/120 is the commonly applied limit for metal wall panels, and the stiffer limits are applied where flat, prominent surfaces make deflection and oil-canning conspicuous. The limit governs panel gauge, profile stiffness, and span between supports. (6.4.4)

6.5 Thermal Transmittance and Bridging

NOTE Metal is a powerful thermal bridge: a metal fastener, clip, or sub-girt that crosses the insulation short-circuits it, and the effective R-value of a metal-clad wall with through-metal attachments can be far below the nominal R-value of the insulation. Factory-foamed IMPs reduce through-metal bridging because the skins are separated by the foam core, but the panel joints and perimeter attachments still bridge; single-skin and open-jointed systems rely on continuous insulation behind the panel, specified in Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation, and on thermally-broken clip systems to limit bridging. (6.5.1)

6.5.2 The opaque metal wall assembly shall meet the assembly U-factor, or the prescriptive insulation requirement, of the adopted energy code (IECC or ASHRAE 90.1) for the climate zone, accounting for the thermal bridging of metal attachments.

Required Assembly U-Factorrange

Btu/(h·ft²·°F)

0.030.0450.0550.0640.0840.12

Per drawings — energy code compliance documents (deferred by default)

6.5.3 The assembly U-factor shall be determined by hot-box test per ASTM C1363 or by a thermal-bridging calculation method that captures the metal attachments, and shall not be determined by summing the nominal R-values of the layers.

6.5.4 For insulated metal panels, the manufacturer shall report the core thermal resistance per ASTM C518 in the product data submittal.

6.6 Fire Performance and NFPA 285

NOTE Fire performance is the most code-critical requirement in this standard, and it turns on whether the assembly contains combustible components — which most modern metal panel walls do, because foam-plastic-core IMPs and polymer-core MCM panels are both combustible, as are most foam-plastic continuous insulations behind single-skin panels. NFPA 285 is a full-scale fire-propagation test of a complete wall assembly: it evaluates whether fire, once started, spreads vertically up the exterior face and through the wall cavity beyond acceptable limits. Compliance is a property of the entire assembly as tested — the specific panel, core, insulation, air and water barrier, framing, and back-up wall, in the tested thicknesses and configuration — and substituting any combustible component or changing the assembly invalidates it. (6.6.1)

6.6.2 Where the exterior wall assembly of a building of Type I, II, III, or IV construction contains a combustible component — foam plastic insulation (IBC Section 2603), metal composite material (IBC Section 1407), or another combustible cladding component — the assembly shall comply with the acceptance criteria of NFPA 285.

6.6.3 NFPA 285 compliance shall be demonstrated by the means selected in the datasheet.

NFPA 285 Compliance Basisradio

○ Passing NFPA 285 test report for the project assembly

○ Test report or engineering judgment by a qualified fire-protection engineer

○ Not triggered (no combustible components in the assembly)

6.6.4 An engineering judgment shall be prepared by a qualified fire-protection engineer and shall extend a passing NFPA 285 test to the proposed configuration within defensible limits, documenting that the as-designed wall is within the bounds of the tested or evaluated assembly.

6.6.5 The Contractor shall not assemble a combustible-component wall on Type I-IV construction without documented NFPA 285 compliance for the as-built assembly, and shall not deviate any combustible-component assembly from its tested or evaluated configuration without renewed compliance documentation.

6.6.6 Metal composite material shall have a flame-spread index of not more than 25 and a smoke-developed index of not more than 450 when tested per ASTM E84 as an assembly in the maximum thickness intended for use, per IBC Section 1407.

6.6.7 Metal composite material shall be separated from the building interior by an approved thermal barrier where required by IBC Section 1407.

6.6.8 Where the wall is required to carry a fire-resistance rating, the panel assembly shall be a listed fire-resistance-rated assembly tested per ASTM E119 (UL 263) for the required rating.

Wall Fire-Resistance Ratingradio

○ Non-rated

○ 1-hour

○ 2-hour

○ 3-hour

Per drawings — code analysis and life-safety drawings (deferred by default)

7 Panel Systems and Materials

7.1 Panel System Family

NOTE The four panel families divide the market by construction and by what the panel does for the wall: (7.1.1)

Insulated metal panels (IMP) deliver the metal skins, the insulation, and the air, water, and vapor control in one factory-foamed component with an engineered interlocking side joint — a fast, single-trade installation with an excellent continuous-insulation value, at the cost of a combustible foam core (unless mineral-wool-cored) that triggers NFPA 285
Single-skin formed and profiled panels are the most economical and architecturally flexible, but they are only the rain-shedding outer layer and rely entirely on a separate air barrier, water-resistive barrier, and insulation behind them
Metal composite material (MCM/ACM) panels — two thin metal skins bonded to a polymer core, routed and returned into cassettes — give a dead-flat, large-format appearance with a thin, light skin, and are tightly governed by IBC Section 1407 and NFPA 285 because of the combustible core
Flat plate and cassette panels give the flush plate appearance in solid (non-laminated) metal with concealed attachment, at higher weight and material cost than MCM

7.1.2 The panel system family shall be as selected and shall be installed as a complete tested system with the manufacturer's matched attachment, closures, and trim.

Panel System Familyradio

○ Insulated metal panel (IMP)

○ Single-skin formed / profiled panel

○ Metal composite material (MCM/ACM)

○ Flat plate / cassette panel

7.1.3 Panel profile, module, joint locations, and layout shall be as shown on the elevations and wall panel details.

7.2 Water-Management Strategy

NOTE The three strategies differ in where the water line of defense sits: (7.2.1)

A pressure-equalized rainscreen provides a vented, compartmentalized cavity behind the panel so cavity pressure equalizes with the exterior; with little pressure difference across the outer joints, far less water is driven through them, and the back-up water-resistive barrier handles the small remainder. It is the highest-performing strategy and is preferred for tall and high-exposure buildings, where wind-driven pressure differences are largest; it is verified to AAMA 508
A drained-and-back-ventilated rainscreen provides the vented, drained cavity without compartmentalization; it is simpler and effective for most buildings, and is verified to AAMA 509
A face-sealed (barrier) wall has no cavity and relies on the integrity of its sealed joints; because every joint is the water line, it carries a permanent joint-inspection and resealing burden and is suited to low, simple, low-exposure walls where that burden is accepted

7.2.2 The water-management strategy shall be as selected, and the panel system, its joints, its flashings, and the back-up wall shall be detailed consistently with it.

Water-Management Strategyradio

○ Pressure-equalized rainscreen (AAMA 508)

○ Drained and back-ventilated rainscreen (AAMA 509)

○ Face-sealed (barrier wall)

7.3 Metal Substrate

NOTE The substrate is selected for corrosion environment, formability, weight, and cost: (7.3.1)

Aluminum is light, corrosion-resistant in most atmospheres, and forms cleanly; it is more expensive per pound and softer — more prone to denting and oil-canning — than steel
Galvanized steel is the most economical and the stiffest common substrate
Galvalume (55% aluminum-zinc-coated) steel gives substantially longer atmospheric service life than galvanized, but the coating is attacked by alkaline runoff from mortar and fresh concrete
Stainless steel, rolled zinc, and copper are specialty substrates for plate and cassette work where the metal itself is the finish; zinc and copper weather to a patina and shed runoff that can stain or corrode materials below

7.3.2 The metal substrate shall be as selected and shall conform to the listed material specification.

Panel Metal Substrateradio

○ Aluminum — ASTM B209

○ Galvanized steel — ASTM A653

○ Galvalume-coated steel — ASTM A792

○ Stainless steel — ASTM A240

○ Rolled zinc — ASTM B69

○ Copper — ASTM B370

7.3.3 Galvanized steel for exterior panels shall have a G90 coating designation minimum; G60 shall not be used for exterior architectural panels.

7.3.4 Galvalume-coated steel shall have an AZ50 coating designation minimum, and shall not be used where it is continuously wetted by alkaline runoff such as mortar or fresh concrete.

7.3.5 Aluminum sheet shall be of an alloy and temper suited to the forming, the finish, and the exposure, per ASTM B209.

7.3.6 Stainless steel shall be Type 304 minimum, and Type 316 where the coastal/marine or severe corrosion exposure category applies.

7.3.7 Runoff from zinc or copper panels shall be directed so that it does not discharge onto aluminum, coated steel, or masonry surfaces it can stain or corrode.

7.4 Skin Thickness and Gauge

NOTE Heavier gauge increases stiffness and dent resistance and reduces oil-canning, but increases weight, forming difficulty, and cost; the workable minimum is set by the span, the design suction, and the flatness the elevation demands. (7.4.1)

7.4.2 The skin thickness or gauge shall meet the structural and deflection requirements of this standard for the panel span, within the manufacturer's tested limits.

7.4.3 The steel skin gauge shall be as selected; where the manufacturer's standard is accepted, the manufacturer shall state the gauge for the tested span and load in the product data submittal.

Steel Skin Gaugeselect

26 ga (0.0179 in)

24 ga (0.0239 in)

22 ga (0.0299 in)

20 ga (0.0359 in)

Manufacturer's standard (by default)

7.4.4 The aluminum skin or plate thickness shall be as selected; where no thickness is selected, the manufacturer's tested thickness for the span and wind pressure shall be used and shall be stated in the product data submittal.

Aluminum Skin / Plate Thicknessrange

in

0.0320.040.050.0630.080.1250.188

7.4.5 For stainless steel, zinc, and copper substrates, the sheet thickness shall be the manufacturer's tested thickness for the span and wind pressure and shall be stated in the product data submittal.

7.5 Insulated Metal Panel Core

NOTE The IMP core is both the insulation and the structural shear connection between the two skins, and the core choice is a direct fire-versus-thermal trade-off. Polyisocyanurate and polyurethane foam cores give high thermal resistance — on the order of R-7 to R-8 per inch — at low weight, but they are foam plastics, are combustible, and invoke NFPA 285 and IBC Section 2603. Mineral-wool cores are non-combustible and achieve listed fire-resistance ratings, and can avoid the NFPA 285 trigger entirely where the rest of the assembly is non-combustible, but at a lower R-value per inch — on the order of R-4 — and substantially higher weight, so a mineral-wool panel is thicker and heavier for the same thermal performance. (7.5.1)

7.5.2 Where an insulated metal panel is used, the core type shall be as selected and shall be consistent with the fire-resistance rating and the NFPA 285 compliance basis of this standard.

IMP Core Typeradio

○ Polyisocyanurate or polyurethane foam

○ Mineral wool

7.5.3 The IMP panel thickness shall be as indicated, consistent with the energy code analysis and the fire-resistance rating where one is required.

IMP Panel Thicknessrange

in

22.53456

Per drawings — wall types on the architectural drawings (deferred by default)

7.6 Metal Composite Material Core

NOTE The distinction between a fire-retardant (FR) core and a standard polyethylene core is consequential: a standard-core MCM relies entirely on the assembly detailing and the NFPA 285-tested configuration to limit fire spread, whereas an FR core is mineral-filled, resists ignition, and contributes far less fuel. Most NFPA 285-tested MCM assemblies on Type I-IV construction are tested with the FR core, which is why it dominates US commercial work. (7.6.1)

7.6.2 Where MCM is used, the core type shall be as selected and shall match the core in the NFPA 285-tested or evaluated assembly for the project.

MCM Core Typeradio

● Fire-retardant (FR) mineral-filled core

○ Standard polyethylene core

○ Not applicable (system is not MCM)

7.6.3 The MCM core shall not contain foam plastic insulation.

7.6.4 The MCM total panel thickness shall be as selected.

MCM Total Panel Thicknessrange

mm

346

7.7 Factory Finishes

NOTE Fluoropolymer (PVDF) coil coatings are the architectural benchmark for exterior metal because of their ultraviolet, color, and chalk resistance, and the AAMA specifications grade the coating tiers by weathering performance: (7.7.1)

AAMA 2605 (70% PVDF on aluminum) and AAMA 621 at the equivalent grade (coil-coated steel) require, after 10 years of South Florida exposure, color change of not more than 5 ΔE per ASTM D2244, chalk rating 8 or better per ASTM D4214, and at least 50% gloss retention per ASTM D523
AAMA 2604 (50% PVDF and silicone-modified polyester blends) carries intermediate weathering requirements at lower cost, suited to moderate exposure
AAMA 2603 (polyester) coatings carry the shortest weathering requirements and are formulated for interior, concealed, and low-exposure use; on prominent exterior elevations they chalk and fade sooner than the higher grades
Anodized aluminum (AAMA 611) is an integral conversion coating rather than an applied film, with excellent hardness and abrasion resistance; color range is narrower and batch-to-batch color matching is more difficult than with coil coatings

7.7.2 The exposed finish system shall be as selected and shall carry the manufacturer's finish warranty required by this standard.

Exposed Finish Systemradio

● 70% PVDF fluoropolymer — AAMA 2605 / AAMA 621

○ 50% PVDF or SMP — AAMA 2604

○ Polyester — AAMA 2603

○ Anodized — AAMA 611

7.7.3 Anodic coatings shall be AAMA 611 Architectural Class I.

7.7.4 The finish color shall be as indicated.

Finish Colortext

Enter value...

Per drawings — finish schedule and elevations (deferred by default)

7.7.5 Panels with metallic or mica finishes shall be fabricated and installed in a consistent coil direction, and the direction shall be marked on each panel, because these finishes shift in color with viewing angle.

8 Attachment and Support

8.1 Attachment Method

NOTE Concealed-fastener systems engage the panel at hidden clips, interlocks, or rout-and-return edges, leaving an unbroken visible face with no fastener penetrations through the weather surface, and they let the panel float for thermal movement. Exposed-fastener systems drive fasteners with sealing washers through the panel face into the support; they are economical and fast for utilitarian single-skin walls, but every fastener is a penetration of the weather face whose service life depends on its washer and on correct driving, and the fastener heads are visible. (8.1.1)

8.1.2 The panel attachment method shall be as selected, and the attachment shall resist the design wind pressures within the manufacturer's tested limits.

Attachment Methodradio

○ Concealed-fastener (clips, interlock, or rout-and-return)

○ Exposed-fastener (fasteners with sealing washers through the panel face)

8.1.3 Exposed fasteners shall have factory-applied sealing washers and shall be driven perpendicular to the panel face, seated without over-driving (washer extruded) or under-driving (washer not compressed).

8.1.4 The clip and fastener spacing shall be reduced in the corner and edge wind zones per the tested capacity and the zone pressures.

8.2 Sub-Framing and Clips

NOTE The sub-framing is the load path from the panel to the building structure and is also, where it crosses the insulation, the principal thermal bridge in the wall. Continuous metal sub-girts bearing directly on continuous insulation crush and short-circuit it; thermally-broken clip-and-rail and spaced-clip systems minimize the through-metal area and are how high-performance walls meet their effective-R targets. (8.2.1)

8.2.2 Panels shall be attached to sub-girts, hat channels, or clips engineered to carry the panel loads to the structure.

Sub-Framing / Clip Systemradio

○ Thermally-broken clip-and-rail over continuous insulation

○ Metal sub-girts or hat channels

○ Direct attachment to sheathing or framing

8.2.3 Thermally-broken clips or an equivalent bridging-mitigation measure shall be used where the energy code compliance path takes credit for continuous insulation crossed by the attachment.

8.2.4 The sub-framing material shall be galvanically compatible with the panel and fastener metals and shall be corrosion-protected for the exposure.

8.3 Fasteners

8.3.1 The fastener material shall be as selected; where the manufacturer's standard is accepted, it shall be the manufacturer's published fastener for the substrate and the corrosion exposure category.

Fastener Materialradio

○ Stainless steel Type 304

○ Stainless steel Type 316

○ Coated carbon steel (long-life organic or zinc-aluminum coating)

Manufacturer's standard (by default)

8.3.2 Fasteners into dissimilar supporting metals shall be isolated per the galvanic-compatibility requirements of this standard.

9 Panel Joints and Sealants

9.1 Panel-to-Panel Joints

NOTE The joint is where panels meet and where most of the air and water management happens, and the joint detail is integral to the tested performance. Interlocking and gasketed joints in IMP and concealed-fastener systems are engineered to drain and to resist air leakage without a face-applied sealant bead; open reveal joints in rainscreen systems are intentionally open and rely on the cavity and the back-up water-resistive barrier, not on a sealed face. (9.1.1)

9.1.2 Panel side and end joints shall be the manufacturer's engineered joint for the system, of the selected type, installed to maintain the joint's air, water, and — for rainscreen systems — pressure-equalization function.

Panel Joint Typeradio

○ Interlocking / shiplap

○ Gasketed dry joint

○ Open reveal

○ Sealed butt joint with backer and sealant

9.1.3 The joint type shall be consistent with the selected water-management strategy.

9.1.4 An open reveal joint shall be used only where a drained cavity and a continuous water-resistive barrier behind the panel manage the water that enters it.

9.1.5 A face-sealed butt joint shall not be relied upon as the water line of defense of a rainscreen wall.

9.2 Field Sealants

NOTE Where sealant is the water line — at face-sealed joints, perimeter and opening conditions, and penetration closures — its movement capability, its adhesion to the factory finish, and the joint geometry govern its life; a rigid sealant bead across a moving joint tears. (9.2.1)

9.2.2 Field sealants at panel joints, perimeters, and terminations shall be approved by the panel manufacturer for the system and shall be compatible with the panel finish.

9.2.3 Sealant adhesion to the factory finish shall be confirmed by the sealant manufacturer's adhesion data on the actual finish, with a primer where the data requires one.

9.2.4 Sealed movement joints shall be sized for the calculated movement and installed over a backer rod to an hourglass profile, and shall not be overfilled.

9.2.5 Perimeter and movement-joint sealant materials are specified in Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants and coordinated with this standard.

10 Flashing and Trim Interface

NOTE The flashings and trim that frame the panel are where the panel system hands off to the rest of the envelope, and they are the most failure-prone part of the installation. The architectural sheet metal itself — metal, gauge, finish, hems, cleats, and joints — is specified in Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current edition.sync/sheet-metal-flashing-and-trim; this standard requires that the panel-to-flashing interface drain, and that it preserve the continuity of the air and water control layers of Air BarriersAir BarriersResolves to the current edition.sync/air-barriers. (10.1)

10.2 The panel system shall interface with the perimeter flashings, copings, base and head closures, sill flashings, and corner and reveal trim so that water reaching the panel system or its cavity is collected and drained to the exterior, and so that the air and water control layers remain continuous across the transition.

10.3 Head flashings over openings and at horizontal interruptions shall extend up behind the water-resistive barrier and shall drain over and beyond the panel face.

10.4 Sill, base, and horizontal transition flashings that collect cavity water shall have end dams and shall drain to the exterior.

10.5 Copings shall shed water away from the panel head, and inside and outside corners shall maintain the joint and drainage continuity of the system.

10.6 Flashing profiles and locations shall be as shown on the head, base, sill, jamb, corner, and parapet details.

11 Testing

11.1 Laboratory Qualification

NOTE Laboratory qualification proves the system performs in a controlled configuration before it is committed to the building. For pressure-equalized rainscreens, the AAMA 508 procedure deliberately perforates the back-up air-barrier plane to simulate an imperfect field installation and then confirms that the cavity still equalizes pressure and that water does not penetrate — a far more realistic test than one that assumes a perfect air barrier. (11.1.1)

11.1.2 The panel system shall be qualified by laboratory testing of the assembly for the selected test package, in a configuration matching the project.

Laboratory Test Package Requiredcheckbox

☑ Air leakage — ASTM E283

☐ Water penetration, static — ASTM E331

☐ Water penetration, dynamic — AAMA 501.1

☐ Structural — ASTM E330 or ASTM E1592

☐ Pressure-equalized rainscreen classification — AAMA 508

☐ Drained and back-ventilated classification — AAMA 509

☐ Pressure cycling — ASTM E1233

11.1.3 Pressure-equalized rainscreen systems shall be classified per AAMA 508, and drained-and-back-ventilated systems per AAMA 509, including the associated pressure-cycling per ASTM E1233.

11.1.4 The Contractor shall submit the laboratory test reports for the assembly configuration matching the project as part of the action submittal package.

11.2 Field Water Testing

NOTE Field water testing catches the installation defects — missed seals, omitted end dams, reversed laps — that laboratory testing of a shop-built specimen cannot. AAMA 501.2 directs a calibrated water spray from a standard nozzle along fixed, permanently sealed joints; it is not used on drained, open, or weep-equipped joints, which are designed to admit and drain water. (11.2.1)

11.2.2 Field water testing of the installed panel system shall be performed where required by the datasheet.

Field Water Testing (AAMA 501.2)radio

○ Required

○ Not required

11.2.3 Where required, the field test shall apply the AAMA 501.2 nozzle method to a representative sample of the most failure-prone conditions — joints, terminations, and penetration closures — on fixed, sealed joints only.

11.2.4 Field testing shall be performed early enough in the installation sequence that defects can be corrected before the wall is enclosed.

11.2.5 Any leak found shall be located, repaired, and re-tested until passing, and the cost of repair and re-testing shall be borne by the Contractor.

12 Installation

12.1 The Contractor shall install the panel system in accordance with this standard, the approved shop drawings, the manufacturer's written instructions, and — where combustible components are present — the NFPA 285-compliant assembly configuration.

12.2 Where those documents conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

12.3 Substrate and Barrier Verification

NOTE Once the panel is up, the air and water barrier behind it cannot be reached without removing the panel, so the inspection regime is front-loaded: acceptance of the barrier before cover-up is a hold point. (12.3.1)

12.3.2 Before panel installation begins, the Contractor shall verify that the back-up wall, the continuous air barrier, and the water-resistive barrier are complete, continuous, inspected, and accepted, and that all transition flashings and penetration seals behind the panel are installed.

12.3.3 The panel installer shall not cover an incomplete or unaccepted air or water barrier.

12.4 Sequence and Trade Coordination

12.4.1 The Contractor shall install the panels and their attachment in the sequence established at the pre-installation conference, coordinated with the flashing, fenestration, and sealant trades, so that flashings that must precede the panel are in place, drainage paths are continuous, and the panel face is not relied upon to seal a condition that should have been flashed behind it.

12.5 Field Cutting and Touch-Up

12.5.1 Field cuts shall be made with tools that do not burn the finish, and cut edges shall be deburred and treated per the manufacturer's instructions.

12.5.2 Field-applied touch-up shall match the factory finish color and shall be limited to minor scratches in concealed or non-prominent areas, because field paint weathers differently than the factory-applied coating.

12.5.3 Panels with visible damage, dents, or cracked finish on prominent surfaces shall be replaced, and where the parties disagree whether a surface is prominent or damage is visible, the Engineer of Record shall make the determination.

13 Delivery, Storage, and Handling

13.1 Panels shall be delivered in the manufacturer's protective packaging with any protective film intact, and shall be stored off the ground, sloped to drain, under cover, and protected from standing water between stacked panels.

13.2 Strippable protective film shall be removed within the manufacturer's stated maximum exposure period, because film left in sunlight bonds to the finish and can mar the coating on removal.

13.3 Panels shall be lifted and carried on edge and shall not be dragged across one another.

13.4 Insulated metal panels shall be protected from point loads that crush the foam core or break the skin-to-core bond.

14 Warranty

NOTE The finish warranty is the long-life warranty that protects the building's appearance, and its available term tracks the finish grade: the higher AAMA finish grades carry the longer published color and chalk warranties. (14.1)

14.2 The Contractor shall warrant the panel installation against leaks, panel disengagement, and defects in workmanship for not less than the selected period from substantial completion.

Contractor Installation Warranty Periodrange

years

1235

14.3 The Contractor shall provide the manufacturer's finish warranty covering film integrity, color change per ASTM D2244, and chalk per ASTM D4214, for not less than the selected period.

14.4 Where no finish warranty period is selected, the manufacturer's published warranty for the specified finish grade shall apply, and its period and terms shall be stated in the action submittal.

Finish Warranty Periodrange

years

51015202530

14.5 A manufacturer's weathertightness or system warranty shall be provided where required by the datasheet.

Manufacturer System / Weathertightness Warrantyradio

○ Required

○ Not required

14.6 Where a system warranty is required and no period is selected, the manufacturer's standard system warranty term shall apply and shall be stated in the action submittal.

System Warranty Periodrange

years

25101520

14.7 The Contractor shall satisfy the manufacturer's stated warranty conditions — approved installer, matched system components, and any required installation documentation.

14.8 Any leak attributable to a defective panel joint, closure, or termination, and any finish failure within the warranted limits, shall be corrected at the Contractor's expense, including repair of collateral damage to adjacent finished work caused by the warranty repair.

15 Spare Parts and Attic Stock

NOTE Custom finish colors can be unavailable years later, and even a standard color from a later coil run may not match the weathered original, so matching replacement stock is procured with the original work. (15.1)

15.2 The Contractor shall deliver to the Owner attic stock of panels, closures, and trim of each panel type, finish, and color, in the selected quantity as a percentage of the installed area of each type.

Attic Stock Quantity (percent of installed panel area, each type and color)range

%

125

15.3 Touch-up finish in each specified color shall be provided in sealed factory containers.