Architectural Precast Concrete
Remade for neutrality: every choice explained, project facts as parameters, scope boundaries linked both ways
Showing changes from Rev 2
to Rev 3
in Architectural Precast Concrete.
---
title: Architectural Precast Concrete
category: Structural / Concrete
−toc_depth: 3
description: >
− When to use: plant-fabricated, finish-grade precast concrete cladding panels
− and trim (spandrels, column covers, window surrounds, cornices, reveal panels,
− medallions, custom profiles) installed as non-loadbearing facade elements on
− commercial, institutional, healthcare, higher-education, and civic buildings;
− covers exposed face-mix selection, surface finish treatment, color/texture
− approval by sample and mockup, cladding connection hardware, erection
− tolerances, field patching, and PCI Group A1 plant certification.
− Not intended for: structural/prestressed members — double-tees, hollow-core
− plank, load-bearing walls, beams, columns (use sync/precast-concrete, the
− upstream production and structural base reference); site-cast tilt-up (use
− sync/cast-in-place-concrete); cast stone (use sync/cast-stone); EIFS (use
− sync/exterior-insulation-and-finish-systems); metal wall panels (use
− sync/metal-wall-panels); joint sealant product selection (use
− sync/joint-sealants); shop painting or galvanizing of embeds (use
− sync/shop-painting-and-galvanizing); precast pipe, culverts, and manholes
− (governed by their own ASTM product standards).
+ When to use: Plant-cast precast concrete units whose exposed face is a specified architectural finish, installed as cladding on the exterior walls of commercial, institutional, healthcare, educational, civic, and multifamily buildings: spandrel panels, full-story wall panels, column covers, cornices, copings, sills, window surrounds, reveal panels, soffit panels, and custom profiled trim, in solid, face-mix-over-backup, and insulated sandwich configurations, with as-cast, form-liner, sandblasted, acid-etched, retarder-exposed-aggregate, bushhammered, honed, polished, thin-brick-faced, and stone-faced finishes. Covers the delegated design of the units and their connections, the face mix and its color, the finish and its acceptance by sample and mockup, reinforcement and connection hardware corrosion protection, the insulation of sandwich panels, joint width, PCI MNL-117 and MNL-135 tolerances, plant certification and quality control, erection, field repair, and cleaning.
+ Not intended for: Structural precast and prestressed members, including double-tees, hollow-core plank, beams, columns, stair units, and loadbearing wall panels with a utility finish, and the structural design, production under PCI MNL-116, prestressing, release strength, and erection of any precast member in its loadbearing role (see [[sync/precast-concrete]]); cast stone trim units produced to ASTM C1364 and set by masons (see [[sync/cast-stone]]); site-cast tilt-up wall panels (see [[sync/tilt-up-concrete]]); cast-in-place concrete and the embedded plates cast into it for precast connections (see [[sync/cast-in-place-concrete]] and [[sync/concrete-accessories]]); the structural steel or concrete frame the panels attach to (see [[sync/structural-steel-framing]] and [[sync/cast-in-place-concrete]]); post-installed anchors into the supporting structure (see [[sync/post-installed-anchors]]); the sealant in the joints between panels and at the panel perimeter (see [[sync/joint-sealants]]); the continuous air barrier behind or through the panels (see [[sync/air-barriers]]); the field-installed wall insulation of an uninsulated panel assembly (see [[sync/building-thermal-insulation]]); sheet metal copings, flashing, and trim (see [[sync/sheet-metal-flashing-and-trim]] and [[sync/through-wall-flashing]]); anchored masonry and stone veneer set unit by unit (see [[sync/masonry-anchorage-and-veneer]]); shop painting of exposed structural steel (see [[sync/shop-painting-and-galvanizing]]); glass fiber reinforced concrete panels, which have no SynC standard; and precast pipe, culverts, manholes, and paving units governed by their own ASTM product standards.
---
# Scope {toc}
−## This standard covers plant-fabricated, finish-grade architectural precast concrete cladding panels and trim units installed as non-loadbearing facade elements. {note}
+## This standard governs precast concrete units whose exposed face is the architectural finish of the building: the delegated design of the unit and its connections, the face mix and its color, the finish and the sample and mockup it is accepted against, the reinforcement and hardware that must not stain or spall that face, the insulation of sandwich panels, the joints between units, the tolerances the finished facade is held to, the plant and erector that produce and set the units, and the repair and cleaning of the face after erection. {note}
−## Architectural precast is precast whose primary purpose is appearance: the exposed concrete face is a finished architectural surface, produced under color, texture, and finish controls that structural precast plants are not equipped to deliver. The work includes selection of exposed face-mix ingredients, surface finish treatment, color and texture approval, cladding connection hardware, erection tolerances and joint coordination, field patching and cleaning, and PCI Group A1 plant certification. {note}
+## Architectural precast differs from structural precast in what is being bought. A structural member is bought for its capacity, and its surface is whatever the form leaves; an architectural unit is bought for its surface, and its capacity is simply what it needs to survive stripping, shipping, erection, and the wind and seismic forces on a cladding element. That inversion is why the units are produced under PCI MNL-117 rather than MNL-116, why the accepted mockup rather than a strength test is the standard the work is judged against, and why color, texture, and dimensional precision are treated here as requirements with the same standing as strength. {note}
−## Included unit types are spandrel panels, column covers, cornices and copings, reveal and window-surround panels, medallions, and custom-profile trim. {note}
+## The units in scope are non-loadbearing cladding: they carry their own weight and the wind and seismic forces applied to them, and they transfer those forces to the building structure through connections designed for the purpose. The structure is designed by others to receive them. {note}
−## Both conventionally reinforced and stainless-reinforced units are covered, in thin-shell-on-backup, solid, and insulated sandwich configurations. {note}
+## Where a unit both carries building load and presents an architectural face, as a loadbearing spandrel or a loadbearing insulated wall panel does, [[sync/precast-concrete]] governs its structural design, its production under PCI MNL-116, its release strength, and its erection as a structural member, and this standard governs its face mix, finish, color, sample and mockup acceptance, and the PCI MNL-117 tolerances of its architectural face. A plant producing such a unit holds certification for both. {note}
−## This standard governs only the non-loadbearing cladding function of these units. {note}
+## The following are coordinated with this standard but specified elsewhere. {note}
−## Where a precast unit simultaneously carries floor or roof gravity load (a loadbearing panel), the structural production, release-strength, and erection-sequence requirements of [[sync/precast-concrete]] also apply and govern the structural function. This standard then governs only the architectural face, finish, and cladding connections of that same unit. {note}
+- Structural precast and prestressed members, and the structural role of any hybrid unit: [[sync/precast-concrete]]
+- Cast stone trim set by masons in mortar: [[sync/cast-stone]]
+- Site-cast tilt-up wall panels: [[sync/tilt-up-concrete]]
+- The cast-in-place concrete frame and the plates and anchor rods cast into it to receive precast connections: [[sync/cast-in-place-concrete]] and [[sync/concrete-accessories]]
+- The structural steel frame and the connection material welded to it: [[sync/structural-steel-framing]] and [[sync/structural-steel-connections]]
+- Anchors drilled into hardened concrete or masonry to receive a precast connection: [[sync/post-installed-anchors]]
+- Welding procedure and welder qualification: [[sync/welding-requirements]]
+- The special inspection agency and the statement of special inspections: [[sync/special-inspections-and-testing]]
+- Sealant in panel joints and at the panel perimeter: [[sync/joint-sealants]]
+- The air barrier plane and its transition to the panels: [[sync/air-barriers]]
+- Wall insulation installed in the field behind uninsulated panels: [[sync/building-thermal-insulation]]
+- Copings, flashing, and trim at the top and base of the panels: [[sync/sheet-metal-flashing-and-trim]] and [[sync/through-wall-flashing]]
+- The windows, curtain wall, and storefront the panels frame: [[sync/glazing]], [[sync/glazed-curtain-walls]], and [[sync/aluminum-entrances-and-storefronts]]
+- Non-shrink grout at bearing connections: [[sync/non-shrink-grout]]
+- Field mockup administration and retention: [[sync/submittal-and-quality-procedures]]
−## Relationship to the structural precast standard. {note}
+## The units shall be designed, produced, and erected in accordance with ACI 318, PCI MNL-117, PCI MNL-120, and PCI MNL-135, and shall comply with [[parameter: adopted-building-code]].
−## [[sync/precast-concrete]] already claims architectural cladding within its broad scope, which suits integrated packages where one producer delivers both structure and skin. This standard is the dedicated, finish-first treatment for projects where the cladding is a separate specialty subcontract or where finish quality is the dominant design driver. It treats [[sync/precast-concrete]] as the upstream production and structural base reference and does not restate its mix-production, prestressing, or structural-member provisions. {note}
+## The size, shape, location, and joint pattern of every unit shall be as indicated on [[drawing: the exterior elevations and panel joint layout]].
−## The following are excluded and are governed by the standards named. {note}
−- Structural and prestressed members — columns, beams, double-tees, hollow-core plank, load-bearing walls, stair units: [[sync/precast-concrete]].
−- Site-cast tilt-up wall panels lifted into place on site: [[sync/cast-in-place-concrete]] (no SynC standard currently covers tilt-up specifically).
−- Cast stone, a fine-grained precast product simulating cut limestone or masonry, with its own matrix and closer masonry-course tolerances: [[sync/cast-stone]].
−- Exterior insulation and finish systems and stucco cladding: [[sync/exterior-insulation-and-finish-systems]].
−- Metal cladding and metal wall panels: [[sync/metal-wall-panels]].
−- Sealant product selection and installation in panel joints: [[sync/joint-sealants]] (this standard sets joint widths and backup requirements but delegates sealant selection).
−- Post-installed anchors into concrete backup: governed by IBC Chapter 17 special inspection and the anchor manufacturer's ICC-ES evaluation report; referenced but not specified here.
−- Shop painting and galvanizing of embedded steel connection hardware: [[sync/shop-painting-and-galvanizing]].
−- Precast concrete pipe, box culverts, manholes, and underground utility products: governed by their own ASTM product standards.
+## This standard states the project-wide policy for the units in the datasheet; the drawings carry the geometry of each unit, and the precast engineer's calculations carry the thickness, reinforcement, and connection of each unit. Where the drawings and the datasheet differ for a given unit, the drawings govern that unit. {note}
−## Panel type. {note}
+## Where the contract documents, the adopted code, and a referenced standard impose conflicting requirements on the same subject, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## The configuration table below records the unit type so that finish, connection, and tolerance requirements track the geometry. Most commercial and institutional facades are dominated by flat spandrel panels. {note}
−
−## The panel type shall be specified for each precast unit so that finish, connection, and tolerance requirements track the panel geometry.
−
−```datasheet
−label: Panel Type
−type: select
−options:
− - Flat spandrel panel
− - Column cover (3- or 4-sided)
− - Window surround / reveal panel
− - Cornice / coping unit
− - Custom-profile trim (pilaster, medallion, band)
− - Flat cladding panel (full-story)
−default: Flat spandrel panel
−```
−
−## Structural role. {note}
−
−## The structural role determines whether the structural provisions of [[sync/precast-concrete]] are layered on top of this standard. Non-loadbearing cladding is the default and the only role this standard fully addresses. {note}
−
−## The structural role of each precast panel shall be specified as loadbearing or non-loadbearing to determine which structural provisions govern the panel design.
−
−```datasheet
−label: Structural Role
−type: radio
−options:
− - Non-loadbearing (cladding only)
− - Loadbearing (also carries floor or roof load)
−default: Non-loadbearing (cladding only)
−```
−
# Referenced Standards {toc}
−## Materials, fabrication, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+## Materials, fabrication, and erection shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard | Title |
|----------|-------|
−| PCI MNL-117-13 | Manual for Quality Control for Plants and Production of Architectural Precast Concrete Products, 4th Edition |
−| PCI MNL-122 | Architectural Precast Concrete (design guide) |
−| PCI MNL-120 | PCI Design Handbook — Precast and Prestressed Concrete, 8th Edition |
−| PCI 135-24 | Specification for Tolerances of Precast Concrete (public-comment draft, 2024) |
−| ACI 318-25 | Building Code Requirements for Structural Concrete and Commentary |
−| ACI 117-10 (R2015) | Specification for Tolerances for Concrete Construction and Materials |
+| ACI 318 | Building Code Requirements for Structural Concrete and Commentary |
+| PCI MNL-117 | Manual for Quality Control for Plants and Production of Architectural Precast Concrete Products |
+| PCI MNL-120 | PCI Design Handbook: Precast and Prestressed Concrete |
+| PCI MNL-122 | Architectural Precast Concrete |
+| PCI MNL-135 | Tolerance Manual for Precast and Prestressed Concrete Construction |
+| ASCE/SEI 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
+| IBC Chapter 17 | International Building Code, Special Inspections and Tests |
+| NFPA 285 | Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components |
| ASTM C150/C150M | Portland Cement |
| ASTM C595/C595M | Blended Hydraulic Cements |
+| ASTM C1157/C1157M | Performance Specification for Hydraulic Cement |
| ASTM C33/C33M | Concrete Aggregates |
+| ASTM C330/C330M | Lightweight Aggregates for Structural Concrete |
+| ASTM C260/C260M | Air-Entraining Admixtures for Concrete |
| ASTM C494/C494M | Chemical Admixtures for Concrete |
| ASTM C618 | Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete |
+| ASTM C989/C989M | Slag Cement for Use in Concrete and Mortars |
| ASTM C1240 | Silica Fume Used in Cementitious Mixtures |
| ASTM C979/C979M | Pigments for Integrally Colored Concrete |
+| ASTM C1602/C1602M | Mixing Water Used in the Production of Hydraulic Cement Concrete |
+| ASTM C31/C31M | Making and Curing Concrete Test Specimens in the Field |
| ASTM C39/C39M | Compressive Strength of Cylindrical Concrete Specimens |
+| ASTM C231/C231M | Air Content of Freshly Mixed Concrete by the Pressure Method |
+| ASTM C1218/C1218M | Water-Soluble Chloride in Mortar and Concrete |
+| ASTM C1088 | Thin Veneer Brick Units Made from Clay or Shale |
+| ASTM C503/C503M | Marble Dimension Stone |
+| ASTM C568/C568M | Limestone Dimension Stone |
+| ASTM C615/C615M | Granite Dimension Stone |
+| ASTM C1242 | Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems |
+| ASTM C578 | Rigid, Cellular Polystyrene Thermal Insulation |
+| ASTM C1289 | Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board |
| ASTM A615/A615M | Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement |
| ASTM A706/A706M | Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement |
−| ASTM A276/A276M | Stainless Steel Bars and Shapes |
−| ASTM A666 | Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar |
+| ASTM A775/A775M | Epoxy-Coated Steel Reinforcing Bars |
+| ASTM A767/A767M | Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement |
+| ASTM A955/A955M | Deformed and Plain Stainless Steel Bars for Concrete Reinforcement |
+| ASTM A1064/A1064M | Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete |
+| ASTM A1022/A1022M | Deformed and Plain Stainless Steel Wire and Welded Wire for Concrete Reinforcement |
+| ASTM D7957/D7957M | Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement |
| ASTM A36/A36M | Carbon Structural Steel |
+| ASTM A307 | Carbon Steel Bolts, Studs, and Threaded Rod, 60 000 PSI Tensile Strength |
+| ASTM F3125/F3125M | High Strength Structural Bolts and Assemblies |
| ASTM A123/A123M | Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products |
| ASTM A153/A153M | Zinc Coating (Hot-Dip) on Iron and Steel Hardware |
−| ASTM C920 | Elastomeric Joint Sealants |
+| ASTM A276/A276M | Stainless Steel Bars and Shapes |
+| ASTM A666 | Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar |
+| ASTM A780/A780M | Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings |
| ASTM C1107/C1107M | Packaged Dry, Hydraulic-Cement Grout (Nonshrink) |
−| AWS D1.1/D1.1M | Structural Welding Code — Steel |
−| IBC Chapter 17 | International Building Code — Special Inspections and Tests |
−| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13, nonstructural components) |
+| AWS D1.1/D1.1M | Structural Welding Code: Steel |
+| AWS D1.4/D1.4M | Structural Welding Code: Steel Reinforcing Bars |
+| AWS D1.6/D1.6M | Structural Welding Code: Stainless Steel |
# Submittals {toc}
## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review and approval before fabrication begins:
−- Product data for cement, aggregates, pigments, admixtures, reinforcement, connection hardware, bearing pads, and grout.
−- Design mix proportions for each face mix and each backup mix, with the water-cementitious materials ratio stated.
−- Shop drawings showing panel elevations, dimensions, reveal and joint patterns, opening locations, reinforcement, embedded hardware, and connection details.
−- Delegated-design connection calculations sealed by a professional engineer registered in the project jurisdiction.
−- Erection drawings showing panel marks, erection sequence, connection assignments, and field-weld and bolt locations.
−- Finish, color, and texture samples and the schedule of required mockups.
+### The Contractor shall submit the following for review before any unit for the project is cast:
+- Shop drawings showing every unit by mark, with its dimensions, profile, reveals, openings, finished faces, reinforcement, embedded hardware, lifting inserts, wythe connectors and insulation where the unit is a sandwich panel, and the connection to the structure for each unit
+- Erection drawings showing the mark and location of every unit, the erection sequence, the connection type at each location, the field welds, bolts, and shims at each connection, the bearing pads, and the grouting required
+- Design calculations for the units and their connections, sealed by the precast engineer
+- The connection load summary for every connection to the structure, stated in the form the Engineer of Record can check against the structural design
+- Mixture proportions for each face mix and each backup mix, identifying every cementitious material, aggregate source, pigment, and admixture, the water-cementitious materials ratio, the design air content, and the specified strength
+- Finish samples for each finish, and range samples where a range of color or texture is accepted
+- Product data for reinforcement and its coating, connection hardware and its coating, wythe connectors, sandwich panel insulation, bearing pads, grout, thin brick or stone facing, and surface sealer
+- Product data for the form liner, with a sample of the liner texture, where a form-liner finish is selected
+
```datasheet
−label: Action Submittals
+label: Action Submittals Required
type: checkbox
options:
− - Product data (materials and hardware)
− - Face and backup mix designs (w/cm stated)
− - Fabrication shop drawings
− - Delegated connection calculations (PE sealed)
− - Erection drawings
− - Finish / color / texture samples and mockup schedule
+ - "Shop drawings for every unit by mark"
+ - "Erection drawings with sequence and connection assignments"
+ - "Sealed design calculations for units and connections"
+ - "Connection load summary for the Engineer of Record"
+ - "Face mix and backup mix proportions"
+ - "Finish samples and range samples"
+ - "Product data for reinforcement, hardware, insulation, pads, grout, facings, and sealer"
+ - "Form liner product data and texture sample"
default:
− - Product data (materials and hardware)
− - Face and backup mix designs (w/cm stated)
− - Fabrication shop drawings
− - Delegated connection calculations (PE sealed)
− - Erection drawings
− - Finish / color / texture samples and mockup schedule
+ - "Shop drawings for every unit by mark"
+ - "Erection drawings with sequence and connection assignments"
+ - "Sealed design calculations for units and connections"
+ - "Connection load summary for the Engineer of Record"
+ - "Face mix and backup mix proportions"
+ - "Finish samples and range samples"
+ - "Product data for reinforcement, hardware, insulation, pads, grout, facings, and sealer"
```
+### No unit shall be cast until the shop drawings for that unit have been reviewed and returned and the finish for that unit has been accepted against the mockup.
+
+### The shop drawings shall be coordinated with the window, curtain wall, and storefront shop drawings before they are submitted, so that every opening dimension, reveal, and embedded receiver for the glazing system is confirmed on both sets.
+
+### A dimensional conflict between precast and glazing found after casting is corrected in the precast only by recasting the unit, because the opening is formed by the unit itself. Resolving it on paper before either trade fabricates is the only inexpensive moment to do it. {note}
+
+### Review of the shop drawings confirms conformance with the design intent of the contract documents and does not relieve the Contractor of responsibility for dimensions, quantities, fit, and coordination with other trades. {note}
+
## Informational Submittals {toc}
−### The Contractor shall submit the following informational submittals:
−- Current PCI plant certification for the producing plant in the required group.
−- Welder qualification records and welding procedure specifications per AWS D1.1.
−- Concrete test reports (release strength and 28-day compressive strength).
−- Producer's quality-control plan and inspection records.
−- Shipping, storage, and handling protection plan.
+### The Contractor shall submit the following before the first unit is cast:
+- The producing plant's current certification under the program this standard requires
+- The precast engineer's license in the project jurisdiction
+- The erector's qualification under the basis this standard requires
+- Welding procedure specifications and welder qualification records for plant and field welding, under [[sync/welding-requirements]]
+- The producer's written quality control program under PCI MNL-117, including the finish comparison procedure, the test frequencies, and the record forms
+- The producer's handling, shipping, and storage plan showing the support points, orientation, and protection of each unit type
+
```datasheet
−label: Informational Submittals
+label: Informational Submittals Required
type: checkbox
options:
− - PCI plant certification
− - Welder qualifications and WPS
− - Concrete strength test reports
− - Producer quality-control plan
− - Shipping / storage / handling plan
+ - "Plant certification"
+ - "Precast engineer's license"
+ - "Erector qualification"
+ - "Welding procedures and welder qualifications"
+ - "Producer's quality control program"
+ - "Handling, shipping, and storage plan"
default:
− - PCI plant certification
− - Welder qualifications and WPS
− - Concrete strength test reports
− - Producer quality-control plan
− - Shipping / storage / handling plan
+ - "Plant certification"
+ - "Precast engineer's license"
+ - "Erector qualification"
+ - "Welding procedures and welder qualifications"
+ - "Producer's quality control program"
+ - "Handling, shipping, and storage plan"
```
+### Concrete strength test reports and the producer's finished-unit inspection records shall be transmitted as they are issued, and the special inspection reports for field connections shall be transmitted as they are issued.
+
## Closeout Submittals {toc}
−### The Contractor shall submit the following closeout submittals before final acceptance:
−- Cleaning and maintenance recommendations for the installed finish.
−- Record erection drawings reflecting as-built panel marks and connections.
−- Special-inspection reports for welding, bolting, and post-installed anchors.
+### The Contractor shall submit the following before the work is accepted:
+- Record erection drawings showing the as-erected mark and connection at every location, with every accepted deviation
+- A record of every unit repaired, with the location and extent of each repair and its acceptance
+- The batch records and constituent sources for each face mix, so that a future repair mix can be matched to the original
+- Cleaning and maintenance instructions for the accepted finish and, where a sealer is applied, the sealer manufacturer's reapplication interval
+- Special inspection reports for welding, bolting, and anchors at the connections, in full
+- Warranties
+
```datasheet
−label: Closeout Submittals
+label: Closeout Submittals Required
type: checkbox
options:
− - Cleaning and maintenance recommendations
− - Record erection drawings
− - Special-inspection reports
+ - "Record erection drawings"
+ - "Repair record"
+ - "Face mix batch records and constituent sources"
+ - "Cleaning and maintenance instructions"
+ - "Special inspection reports"
+ - "Warranties"
default:
− - Cleaning and maintenance recommendations
− - Record erection drawings
− - Special-inspection reports
+ - "Record erection drawings"
+ - "Repair record"
+ - "Face mix batch records and constituent sources"
+ - "Cleaning and maintenance instructions"
+ - "Special inspection reports"
+ - "Warranties"
```
# Quality Assurance {toc}
−## Why architectural precast carries its own QA regime. {note}
+## Plant Certification {toc}
−## The finished concrete face is the deliverable. Color uniformity, finish texture, and dimensional precision are achieved through plant disciplines — mockup-controlled finishing, segregated face and backup placement, pigment batching control, and per-panel finish comparison — that a structural precast plant certified only for load-carrying members may not maintain. Specifying architectural cladding under the structural section without invoking PCI MNL-117 and Group A1 certification is a recurring and costly error: structural plants lack the finishing expertise, color controls, and sample-approval workflows that finish-grade work requires. {note}
+### The units shall be produced in a plant holding the certification indicated in the datasheet for the duration of production.
−### The producing plant shall hold current PCI plant certification in the group required below for the duration of fabrication.
−
−### Architectural cladding panels and trim shall be produced under PCI Group A1 (Architectural) certification unless an equivalent program is accepted below.
−
```datasheet
−label: Required Plant Certification
−type: radio
+label: Plant Certification
+type: select
options:
− - PCI Group A1 (Architectural)
− - PCI Group B (Structural) — Engineer-accepted
− - NPCA certification — Engineer-accepted alternative
−default: PCI Group A1 (Architectural)
+ - "PCI Plant Certification Program, Category A1, Architectural Concrete Products"
+ - "PCI Plant Certification Program, Category C1A through C4A, Commercial Structural Products with an Architectural Finish"
+ - "CPCI Certification Program, Architectural Precast Products"
+ - "Audited quality program evaluated by the Engineer of Record as equivalent to PCI MNL-117"
+default: "PCI Plant Certification Program, Category A1, Architectural Concrete Products"
```
−## Plant certification group. {note}
+### Category A1 certifies a plant against PCI MNL-117 in full, including the finish comparison, color control, and tolerance disciplines a non-loadbearing architectural unit is judged by, and it is the category the industry expects a cladding scope to be produced under. The A-suffixed commercial categories certify a structural plant that also produces finished faces, and they fit a project whose architectural units are loadbearing members that [[sync/precast-concrete]] governs structurally. CPCI certification is the Canadian equivalent, relevant where the nearest qualified plant is across the border. An audited program evaluated by the Engineer of Record is the arrangement where no certified plant is within economic haul distance, and it puts the burden of judging the plant's controls on the Engineer of Record rather than on a third-party audit. {note}
−## Group A1 is the architectural certification and is the default for finish-grade cladding. Group B (structural) is acceptable only for plain, non-color-critical units where the Engineer accepts it in writing. An NPCA certification may be accepted as an alternative where the Engineer determines the producer's architectural controls are equivalent. {note}
+### Where the parties disagree whether a quality program is equivalent to PCI MNL-117, the Engineer of Record shall make the initial determination.
−### Welding of connection hardware shall be performed by welders qualified under AWS D1.1 within the preceding 12 months.
+### A plant whose certification lapses during production shall notify the Engineer of Record within seven days, and no unit cast after the lapse shall be shipped until the certification is reinstated or the Engineer of Record accepts the plant's quality records for those units in writing.
−### Field welding, high-strength bolting, and post-installed anchors at panel connections shall be subject to special inspection in accordance with IBC Chapter 17.
+## Precast Engineer {toc}
−## Special inspection is mandatory and is a life-safety requirement, not a discretionary one. {note}
+### The units and their connections shall be designed by a professional engineer licensed in the project jurisdiction and retained by the producer, referred to in this standard as the precast engineer.
−## Connection failures at cladding panels are a falling-hazard risk to occupants and the public. The IBC Chapter 17 special-inspection program shall list welding, high-strength bolting, and post-installed anchors at precast connections; omitting them from the program is a defect that must be corrected before connections are concealed. {note}
+### The precast engineer shall seal the design calculations, the shop drawings, and the erection drawings.
−## Sample Panels and Mockups {toc}
+### The Engineer of Record designs the structure to receive the panel loads shown on the structural drawings; the precast engineer designs the panel and every connection to carry those loads into that structure. The two designs meet at the connection load summary, which is why that summary is an action submittal rather than a calculation buried in the producer's package. {note}
−### The producer shall furnish finish samples and mockups as scheduled below, and no production unit shall be cast for the project until the corresponding finish, color, and texture are accepted in writing.
+## Erector Qualification {toc}
+### The units shall be erected by an erector qualified on the basis indicated in the datasheet.
+
```datasheet
−label: Mockup Requirement
+label: Erector Qualification Basis
type: radio
options:
− - Tabletop sample only (4 ft x 4 ft)
− - Tabletop sample plus full-size wall-panel mockup (8 ft x 8 ft)
− - In-place building mockup panel (remains in the work)
−default: Tabletop sample plus full-size wall-panel mockup (8 ft x 8 ft)
+ - "PCI Erector Certification Program, Category A, Architectural Precast"
+ - "Record of comparable completed architectural precast projects accepted by the Engineer of Record"
```
−## Why a full-size mockup is often required. {note}
+### PCI erector certification audits the erector's crews, rigging, and connection practice against a published program, and it is held by the erectors who do this work regularly; a project record puts the same questions to the Engineer of Record and fits a region where certified erectors are not available or where the producer erects its own product under its plant quality program. {note}
−## A tabletop laboratory sample cannot capture how pigment, aggregate gradation, and finish treatment interact at full scale under natural light. On color-critical facades a 4 ft x 4 ft sample is approved for the finish character, but an 8 ft x 8 ft full-size wall-panel mockup is needed to validate color and texture as the eye will read them on the building. Omitting the full-size mockup on a color-critical facade produces rejected production panels and field RFIs. {note}
+### Where the parties disagree whether a listed project is comparable, the Engineer of Record shall make the initial determination.
−### Tabletop finish samples shall be a minimum of 4 ft x 4 ft and shall establish the accepted finish character, aggregate exposure, and texture.
+## Welding and Special Inspection {toc}
−### For color-critical or complex finishes, a full-size wall-panel mockup of at least 8 ft x 8 ft shall be produced and accepted before production casting.
+### Welding of carbon steel connection hardware shall conform to AWS D1.1/D1.1M, welding of reinforcing bars shall conform to AWS D1.4/D1.4M, and welding of stainless steel hardware shall conform to AWS D1.6/D1.6M, under the procedures and qualifications of [[sync/welding-requirements]].
−### Where a range of acceptable color is established, the producer shall furnish range panels representing the light, medium, and dark acceptance limits, and production shall fall within that range.
+### Field welding, high-strength bolting, and post-installed anchors at the panel connections shall be subject to special inspection in accordance with IBC Chapter 17, administered under [[sync/special-inspections-and-testing]].
−## Mockup scope. {note}
+### The producer's plant quality control under PCI MNL-117 shall be accepted in place of special inspection of plant fabrication where [[parameter: adopted-building-code]] permits fabrication by an approved fabricator.
−## The required level of mockup is recorded below so that bidders price it correctly. In-place building mockup panels are reserved for the most finish-sensitive projects, where the mockup remains in the completed work. {note}
+## Finish Samples and Mockup {toc}
−## Factory Quality Control {toc}
+### The producer shall furnish finish samples not less than 12 in. by 12 in. for each finish, cast with the proposed face mix and treated by the proposed method, and no unit shall be cast until the finish sample for its finish is accepted.
−### The producer shall cast and test a minimum of four compressive-strength cylinders per 50 yd³ of face mix and not fewer than four per mix per production day, tested per ASTM C39.
+### Where the accepted finish is a range rather than a single appearance, the producer shall furnish range samples representing the lightest and darkest color and the least and greatest texture that will be accepted, and every production unit shall fall within that range.
−### Each finished unit shall be compared against the accepted mockup at the plant before shipment, and units outside the accepted color and finish range shall be rejected.
+### The producer shall furnish the mockup indicated in the datasheet, and no production unit of a given finish shall be cast until the mockup of that finish has been accepted in writing.
−# Environmental and Service Conditions {toc}
+```datasheet
+label: Mockup
+type: radio
+options:
+ - "Full-size sample unit cast and finished at the plant"
+ - "First production unit of each finish, held for acceptance before the balance is cast"
+ - "Field mockup erected on site with the adjoining window, air barrier, flashing, and sealant work"
+```
−## Exposure drives material durability selection. {note}
+### A sample unit cast at the plant shows the finish at full scale and under daylight before any production unit exists, and it can include a return, a reveal, and a joint so that the corners and edges the small sample cannot show are judged with the field. Holding the first production unit for acceptance costs no extra casting but puts the schedule at risk if it is rejected, because every later unit waits on the recast. A field mockup is the only one that shows the precast against the glazing, the flashing, and the sealant it will meet, and it is the one that catches an interface problem; it is also the most expensive, and it is the practice where the facade is a performance-tested assembly under [[sync/submittal-and-quality-procedures]]. {note}
−## Exterior cladding is exposed to wind-driven rain, freeze-thaw cycling, ultraviolet light, and — within roughly one mile of saltwater — chloride-laden coastal air. These exposures govern the water-cementitious ratio of the face mix, the corrosion protection of embedded steel, and whether stainless reinforcement is warranted at thin cover. {note}
+### The accepted mockup shall be the standard of acceptance for the finish, color, texture, and workmanship of every unit of that finish, and the accepted finish and range samples shall be the standard where the mockup cannot be brought to the point of comparison.
−## Service exposure category. {note}
+### The accepted mockup and samples shall be retained, protected from weathering and staining, and available for comparison at the plant throughout production and at the site throughout erection, until the last unit of that finish is accepted; a field mockup shall be retained to the milestone set under [[sync/submittal-and-quality-procedures]].
−## The exposure category below selects the durability defaults applied later in this standard. The coastal category triggers stainless embeds and is appropriate for sites within one mile of saltwater. {note}
+### Finish, color, and texture shall be judged in daylight, without direct sun on the surface, at the viewing distance indicated in the datasheet.
−## The service exposure of each panel shall be specified, using the coastal category for sites within one mile of saltwater, to establish the applicable durability requirements.
+```datasheet
+label: Finish Acceptance Viewing Distance
+type: range
+unit: ft
+options:
+ min: 10
+ max: 50
+ setpoints: [10, 20, 30, 50]
+default: 20
+```
+### Twenty feet is the distance PCI MNL-117 uses to judge an architectural finish, and it is roughly the distance from which a pedestrian sees a facade. A shorter distance makes every bug hole and color mottle a defect that no one on the sidewalk will ever see, and a longer one lets a visibly uneven finish through on a low building. {note}
+
+### Where the parties disagree whether a unit matches the accepted mockup, the Engineer of Record shall make the initial determination.
+
+# Environmental and Service Conditions {toc}
+
+## Exposure Classes {toc}
+
+### The Engineer of Record shall assign the ACI 318 freeze-thaw and corrosion-protection exposure classes for the units and shall record them in the datasheet.
+
```datasheet
−label: Service Exposure
+label: Freeze-Thaw Exposure Class
type: select
options:
− - Interior / protected
− - Exterior, non-coastal
− - Exterior, coastal (within 1 mile of saltwater)
−default: Exterior, non-coastal
+ - "F0, not exposed to freezing-and-thawing cycles"
+ - "F1, exposed to freezing-and-thawing cycles with limited exposure to water"
+ - "F2, exposed to freezing-and-thawing cycles with frequent exposure to water"
+ - "F3, exposed to freezing-and-thawing cycles with frequent exposure to water and to deicing chemicals"
```
−### Face mix for exterior exposure shall be proportioned for a maximum water-cementitious materials ratio of 0.40.
−
```datasheet
−label: Maximum Water-Cementitious Materials Ratio (Face Mix)
−type: range
−min: 0.36
−max: 0.45
−step: 0.01
−default: 0.40
−unit: w/cm
+label: Corrosion-Protection Exposure Class
+type: select
+options:
+ - "C0, concrete dry or protected from moisture in service"
+ - "C1, concrete exposed to moisture but not to an external source of chlorides"
+ - "C2, concrete exposed to moisture and to an external source of chlorides"
```
−## Seismic and wind demand. {note}
+### The classes follow from where the unit sits. A vertical cladding face in a freezing climate sheds water and is F1; a coping, sill, spandrel top, or soffit edge where water stands or drips is F2; a unit within splash reach of pavement treated with deicing salt is F3; an interior unit, or any unit in a climate that does not freeze, is F0. An exterior unit is C1 everywhere, and C2 on a coastal site exposed to salt spray or where deicing salt reaches it. A single project commonly carries two classes, one for the field of the wall and one for the base and the horizontal surfaces. {note}
−## Cladding panels and their connections are nonstructural components under ASCE 7 Chapter 13. Connection design forces are derived from the Chapter 13 Fp equation, with a component importance factor Ip = 1.0 for typical cladding. Connections shall accommodate the seismic story drift of the supporting structure without transferring in-plane frame load into the panel. {note}
+### The face mix and the backup mix shall satisfy the maximum water-cementitious materials ratio, the minimum specified compressive strength, the air content, and the maximum water-soluble chloride ion content that ACI 318 Table 19.3.2.1 requires for the assigned classes.
−### Cladding panels and connections shall be designed for the wind and seismic forces determined under ASCE 7, including the Chapter 13 nonstructural-component provisions.
+### The water-soluble chloride ion content of the hardened concrete shall be determined in accordance with ASTM C1218/C1218M at the age ACI 318 requires.
−### Connections shall accommodate the seismic and thermal movements of the supporting structure without inducing load into the panel face.
+## Design Loads and Movement {toc}
−### Precast connections shall not rigidly bridge a building expansion or seismic separation joint.
+### The units and their connections shall be designed for their self-weight, for the wind pressures and the seismic forces on exterior nonstructural wall elements determined under ASCE/SEI 7 for [[parameter: seismic-design-category]], and for the stripping, handling, shipping, and erection forces the producer's methods impose.
−## Why panels must not bridge separation joints. {note}
+### The design wind pressures, the story drift, and the structural member movements the connections must accommodate shall be as indicated on [[drawing: the structural drawings]].
−## A connection that rigidly spans a building expansion or seismic separation joint will be torn in the first significant thermal cycle or seismic event. Separation joints in the cladding shall be located to coincide with the structure's expansion and seismic joints.
+### The connections shall accommodate the design story drift of the supporting structure, the thermal movement of the unit relative to the structure, and the deflection of the supporting members, without transferring in-plane frame forces into the unit and without the unit bearing on any element not designed to support it.
−# Concrete Materials and Mix {toc}
+### The connections shall not restrain the unit across a building expansion or seismic separation joint, and the joint pattern of the units shall provide a joint at every such separation.
−## Face mix versus backup concrete. {note}
+### A cladding panel attached rigidly at both top and bottom becomes a structural element the moment the frame drifts, and the forces that go into it were never in anyone's calculation. The convention is a bearing connection that carries gravity and an out-of-plane tieback that slides or flexes in plane, so that the frame moves and the panel rides along; which connection is fixed and which is released is the precast engineer's decision, but the principle that the panel is released is not. {note}
−## A thin-shell architectural panel is cast in two concretes placed wet-on-wet: an exposed face mix carrying the cement, aggregate, and pigment that produce the finish, bonded to a grey backup concrete carrying the reinforcement and connection embeds. The face mix is selected for appearance and durability; the backup concrete for strength and economy. On solid panels a single architectural mix is used throughout. {note}
+### Insulated sandwich panels containing foam plastic insulation shall comply with the foam plastic provisions of [[parameter: adopted-building-code]], including any exterior wall fire propagation test the code requires for the assembly.
−### Portland cement shall conform to ASTM C150/C150M; blended hydraulic cements for backup concrete shall conform to ASTM C595/C595M.
+# Panel Configuration {toc}
−### Face-mix cement color shall match the accepted mockup, using white cement, grey cement, or a blend as required to achieve the accepted color.
+## Face Mix Construction {toc}
−### Fine and coarse aggregates shall conform to ASTM C33/C33M as a minimum, and facing aggregates shall meet or exceed those limits.
+### The units shall be cast with the face mix construction indicated in the datasheet.
−### Chemical admixtures shall conform to ASTM C494/C494M; integral color pigments shall conform to ASTM C979/C979M; silica fume, where used, shall conform to ASTM C1240.
+```datasheet
+label: Face Mix Construction
+type: radio
+options:
+ - "Face mix over backup concrete, placed wet on wet"
+ - "Single homogeneous mix through the full thickness"
+default: "Face mix over backup concrete, placed wet on wet"
+```
−### Fly ash with dark or variable color shall not be used in exposed face mixes.
+### A separate face mix puts the white cement, selected aggregate, and pigment only where they are seen, and it is the way most architectural units are produced; a homogeneous mix is used where the unit is thin, where finished faces occur on several sides so that a face layer cannot be placed on all of them, or where the facing materials are inexpensive enough that the saving does not cover the second placement. {note}
−## Why fly-ash color matters in the face. {note}
+### Where a face mix is placed over backup concrete, the face mix shall be not less than 1 in. thick after the finish treatment, and not less than 1.5 times the maximum facing aggregate size, measured at every point of the finished face.
−## Variable-color fly ash conforming to ASTM C618 is acceptable structurally but causes uncontrolled batch-to-batch color variation in an exposed face. Specify white-cement face mixes, or confirm a consistent fly-ash color with the producer before approving the face-mix design. {note}
+### The backup concrete shall be placed on the face mix before the face mix reaches initial set, so that the two are consolidated together without a cold joint.
−## Face Mix Selection {toc}
+### The face mix and the backup mix shall have compatible shrinkage and thermal characteristics, and the producer shall demonstrate compatibility by a record of prior production or by a trial unit.
−## Cement color and aggregate define the field color. {note}
+### A face layer that shrinks at a different rate from its backup bows the unit and can delaminate at the interface, and the defect appears months after erection. Compatibility is a matter of the two mixes sharing an aggregate source and a comparable paste content, which is why the producer is asked to show it rather than assert it. {note}
−## The base color of the panel is set by the cement (white, grey, or blended), the facing aggregate (local crushed stone, quartz, marble, granite chips, or river gravel), the maximum aggregate size, and any integral pigment. These choices are recorded below and locked against the accepted mockup. {note}
+## Insulated Sandwich Panels {toc}
−## The face-mix cement type shall be specified and locked against the accepted mockup to establish the panel's base color.
+### The units shall be insulated as indicated in the datasheet.
```datasheet
−label: Face-Mix Cement
+label: Panel Insulation
type: radio
options:
− - White portland cement
− - Grey portland cement
− - White/grey blend
−default: Grey portland cement
+ - "Uninsulated"
+ - "Insulated sandwich, with insulation cast between an exterior wythe and an interior wythe"
```
−## The facing aggregate for the face mix shall be specified and locked against the accepted mockup to establish the panel's base color.
+### Where the units are insulated sandwich panels, the wythes shall be joined by the connectors indicated in the datasheet.
```datasheet
−label: Facing Aggregate
+label: Wythe Connector Type
type: select
options:
− - Local crushed stone
− - Quartz
− - Marble chips
− - Granite chips
− - River gravel
−default: Local crushed stone
+ - "Non-conductive fiber-composite or polymer connectors"
+ - "Stainless steel pins or ties"
+ - "Galvanized steel trusses or solid concrete zones through the insulation"
```
−## The maximum facing aggregate size for the face mix shall be specified and locked against the accepted mockup to establish the panel's base color.
+### Non-conductive connectors carry no measurable heat through the insulation, so the panel's thermal resistance is close to that of the insulation alone, and they are the choice where the panel is the envelope's insulation layer; whether they make the wythes act compositely is a property of the specific connector and is settled by the precast engineer. Stainless pins conduct less than carbon steel and tolerate the moisture in the insulation plane, at a higher cost per connector. Steel trusses and solid concrete ribs give the stiffest composite panel and the cheapest connection, and they bridge the insulation so thoroughly that the panel's effective thermal resistance can fall well below the insulation's rated value. {note}
+### The sandwich panel insulation shall be the type indicated in the datasheet, conforming to ASTM C578 for polystyrene and to ASTM C1289 for polyisocyanurate.
+
```datasheet
−label: Maximum Facing Aggregate Size
+label: Sandwich Panel Insulation Type
type: select
options:
− - 3/8 in.
− - 1/2 in.
− - 3/4 in.
− - 1 in.
−default: 3/8 in.
−unit: in.
+ - "Extruded polystyrene"
+ - "Expanded polystyrene"
+ - "Polyisocyanurate"
```
−### Integral pigment, where used, shall be iron-oxide pigment conforming to ASTM C979/C979M, dosed by weight of cementitious material.
+### Extruded polystyrene holds its thermal resistance in the damp interior of a sandwich panel and resists the crushing of consolidation, and it is the most common choice. Expanded polystyrene is less costly per unit of thermal resistance and is available in greater thickness, at a lower resistance per inch and with more water absorption. Polyisocyanurate gives the highest resistance per inch, so it fits a panel whose total thickness is constrained, and its facers and its long-term thermal drift are the properties to check against the connector system and the energy calculation. {note}
+### The thermal resistance of the sandwich panel insulation shall be as indicated in the datasheet.
+
```datasheet
−label: Pigment Loading (by weight of cementitious)
+label: Sandwich Panel Insulation Thermal Resistance
type: range
−min: 0
−max: 10
−step: 1
−default: 0
−unit: "%"
+unit: "h ft² °F/Btu"
+derived: "the opaque wall assembly requirement of [[parameter: adopted-energy-code]] for [[parameter: climate-zone]], net of the connector and solid-zone thermal bridging"
+options:
+ min: 5
+ max: 40
+ step: 1
+default: derived
```
−## Pigment loading. {note}
+### The thermal resistance of a sandwich panel is credited at the value established for the assembly including its connectors and solid zones, not at the rated value of the insulation board.
−## Iron-oxide pigment is typically dosed between 3% and 8% by weight of cementitious material; loading above this range yields diminishing color return and raises cost. The accepted mockup, not the dosage number, is the acceptance reference. {note}
+### The insulation shall be continuous through the panel, interrupted only by the connectors and by solid zones the precast engineer requires, and solid zones shall be shown on the shop drawings so that the energy calculation can account for them.
−## Compressive Strength {toc}
+### Where the units are uninsulated, the wall insulation installed behind them is specified in [[sync/building-thermal-insulation]], and the continuous insulation is coordinated with the connection hardware so that the connections do not require the insulation to be cut away. {note}
−### Face-mix concrete shall attain a minimum 28-day compressive strength of 5,000 psi.
+# Concrete Materials and Mixtures {toc}
+## Cementitious Materials and Aggregates {toc}
+
+### Cement shall conform to ASTM C150/C150M, ASTM C595/C595M, or ASTM C1157/C1157M, and the cement for each face mix shall be from a single source and a single type for the duration of production.
+
+### Supplementary cementitious materials, where used, shall conform to ASTM C618, ASTM C989/C989M, or ASTM C1240, and shall be from a single source for the duration of production.
+
+### Aggregates shall conform to ASTM C33/C33M, or to ASTM C330/C330M where lightweight backup concrete is used, and facing aggregate shall be from a single source and a single gradation for the duration of production.
+
+### Admixtures shall conform to ASTM C260/C260M for air entrainment and to ASTM C494/C494M for chemical admixtures, and no admixture containing calcium chloride shall be used in any mix.
+
+### Mixing water shall conform to ASTM C1602/C1602M.
+
+### Pigment, where used, shall be a synthetic iron oxide conforming to ASTM C979/C979M, batched by weight to a tolerance of 1 percent of the pigment dose, and shall not exceed 10 percent of the weight of cementitious material.
+
+### Color in an architectural face comes from the cement, the fine aggregate, the pigment, and the water-cementitious materials ratio in roughly that order of influence, and a change in any one of them between batches reads as a color change on the building. The single-source requirements hold the inputs constant for the length of the project; the mockup settles what those inputs look like. {note}
+
+### Fly ash with a variable carbon content or color shall not be used in a face mix unless the face mix containing it is the mix the mockup was cast from.
+
+## Face Mix Color {toc}
+
+### The face mix shall be proportioned with the cement indicated in the datasheet and with the facing aggregate and pigment required to match the accepted finish sample.
+
```datasheet
−label: Face-Mix 28-Day Compressive Strength (min)
−type: range
−min: 5000
−max: 7000
−step: 500
−default: 5000
−unit: psi
+label: Face Mix Cement Color
+type: radio
+options:
+ - "White portland cement"
+ - "Gray portland cement"
+ - "Blend of white and gray portland cement"
```
−### Backup concrete shall attain a minimum 28-day compressive strength of 4,000 psi.
+### White cement is the base for light and pigmented colors and gives the most uniform color from batch to batch, at the highest material cost and with the least tolerance for a dirty aggregate. Gray cement varies in shade from mill to mill and from shipment to shipment, so it needs the single-source discipline most, and it is the base for natural gray and dark finishes at the lowest cost. A blend reaches the mid-tones that neither cement reaches alone, and it adds one more proportion the plant must hold constant. {note}
+### The color and finish of each unit shall be as indicated in the datasheet.
+
```datasheet
−label: Backup Concrete 28-Day Compressive Strength (min)
+label: Face Color and Finish Reference
+type: text
+drawing_ref: "the exterior finish schedule and finish legend"
+default: deferred
+```
+
+### The color is recorded as the reference to the accepted sample, not as a description. A color named in words has no acceptance criterion; a color matched to an accepted sample at the specified viewing distance has one. {note}
+
+### The maximum water-cementitious materials ratio of the face mix shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Water-Cementitious Materials Ratio, Face Mix
type: range
−min: 4000
−max: 6000
−step: 500
−default: 4000
−unit: psi
+unit: w/cm
+derived: "the ACI 318 exposure classes assigned to the units"
+options:
+ min: 0.30
+ max: 0.50
+ step: 0.01
+default: derived
```
−### Units shall attain the release strength required for stripping and handling before being removed from the form, as determined by the delegated engineer.
+### A low water-cementitious materials ratio does more for an architectural face than durability: it reduces the paste that bleeds to the form face, which is the source of color mottling and of the surface voids every finish treatment is partly intended to hide. The ratio the exposure class requires is a ceiling, and a producer running a finish-grade face mix is usually well under it. {note}
−## Release strength. {note}
+## Compressive Strength {toc}
−## Units must reach a handling-safe strength before stripping; a common default is 3,500 psi, but the delegated engineer may require higher where panel geometry or lifting stresses demand it.
+### The specified compressive strength of the face mix at 28 days shall be as indicated in the datasheet, and not less than the strength ACI 318 requires for the assigned exposure classes.
```datasheet
−label: Release Strength for Handling (min)
+label: Specified Compressive Strength at 28 Days, Face Mix
type: range
−min: 3000
−max: 4500
−step: 250
−default: 3500
unit: psi
+options:
+ min: 4000
+ max: 8000
+ setpoints: [4000, 5000, 6000, 7000, 8000]
+default: 5000
```
−# Reinforcement and Embedded Hardware {toc}
+### The specified compressive strength of the backup concrete at 28 days shall be as indicated in the datasheet.
−## Reinforcement choice follows cover and exposure. {note}
+```datasheet
+label: Specified Compressive Strength at 28 Days, Backup Concrete
+type: range
+unit: psi
+options:
+ min: 4000
+ max: 8000
+ setpoints: [4000, 5000, 6000, 7000, 8000]
+default: 5000
+```
−## Conventional carbon-steel reinforcement is standard, but the minimum cover required to protect it (1.5 in. for exterior carbon steel per ACI 318-25 Table 20.6.1.3) can exceed the thickness available in a thin face wythe. Stainless reinforcement permits a reduced cover of about 0.75 in., which is why thin panels and coastal projects increasingly use Type 316 stainless or fiber-reinforced-polymer bars. {note}
+### Five thousand psi is the strength PCI MNL-117 sets for architectural precast, and it is reached without effort by a face mix proportioned for a low water-cementitious materials ratio. A higher strength is specified where the precast engineer needs it for a thin or long unit, not for durability, which the exposure class already covers. {note}
−### Deformed carbon-steel bars shall conform to ASTM A615/A615M Grade 60; in Seismic Design Categories D through F, bars shall conform to ASTM A706/A706M where required by ACI 318.
+### The release strength at which a unit may be stripped from the form and handled shall be determined by the precast engineer from the stripping and handling analysis and shall be stated on the shop drawings for each unit.
−### Stainless reinforcing bars, where specified, shall conform to ASTM A276/A276M, Type 304 or Type 316.
+### A unit shall not be stripped, lifted, or shipped until test specimens cured with the unit demonstrate that it has reached the release strength stated for it.
−### Carbon-steel reinforcement in exterior exposure shall have a minimum concrete cover of 1.5 in. per ACI 318-25 unless protected by an accepted alternative.
+# Reinforcement {toc}
−## Reinforcement type. {note}
+## Deformed bars shall conform to ASTM A615/A615M Grade 60 or ASTM A706/A706M Grade 60, and bars that are welded shall conform to ASTM A706/A706M.
−## The reinforcement system is recorded below so that cover, panel thickness, and corrosion protection are coordinated. Stainless is the durable choice for thin and coastal panels; carbon steel with adequate cover suits typical exterior work. {note}
+## Welded wire reinforcement shall conform to ASTM A1064/A1064M, or to ASTM A1022/A1022M where stainless steel reinforcement is selected.
−## The reinforcement type shall be specified so that panel cover, thickness, and corrosion protection are coordinated with the selected reinforcement system.
+## Reinforcement shall be protected against corrosion by the system indicated in the datasheet.
```datasheet
−label: Reinforcement Type
+label: Reinforcement Corrosion Protection
type: select
options:
− - Carbon steel (ASTM A615 Grade 60)
− - Carbon steel, epoxy-coated
− - Carbon steel, hot-dip galvanized
− - Stainless steel Type 304
− - Stainless steel Type 316
−default: Carbon steel (ASTM A615 Grade 60)
+ - "Uncoated carbon steel"
+ - "Epoxy-coated carbon steel, ASTM A775/A775M"
+ - "Hot-dip galvanized carbon steel, ASTM A767/A767M"
+ - "Stainless steel, ASTM A955/A955M"
+ - "Glass fiber reinforced polymer bars, ASTM D7957/D7957M"
```
−## Embedded Connection Hardware {toc}
+## Uncoated carbon steel relies entirely on the cover and the density of the concrete, and in a C1 unit with the cover this standard requires that is the protection most cladding is built with. Epoxy coating adds a barrier that is only as good as its handling, because a nick at a tie or a bend is where the bar corrodes first, and the coating prevents welding. Galvanizing tolerates handling damage and can be welded with the right procedure, at a cost between epoxy and stainless, and it is the protection that fits a thin unit where the cover cannot be held. Stainless steel removes the corrosion question for the life of the building and fits a C2 unit or an exposed edge, at several times the bar cost. Fiber-reinforced polymer bars cannot corrode and weigh a quarter of steel, and they fit a thin unit where no steel cover can be achieved; they are not ductile, they cannot be bent in the field, and the precast engineer designs with them under a different code than ACI 318. {note}
−### Embedded plates, angles, and weld-on studs of carbon steel shall conform to ASTM A36/A36M.
+## Concrete cover over reinforcement shall satisfy ACI 318 Table 20.5.1.3.3 for precast concrete manufactured under plant control conditions, measured from the finished surface after the finish treatment has removed its depth of paste and aggregate.
−### Carbon-steel embeds in exterior service shall be hot-dip galvanized to ASTM A123/A123M, Class C minimum (1.5 oz/ft²); bolts, nuts, and miscellaneous hardware shall be galvanized to ASTM A153/A153M.
+## The depth an exposed-aggregate or blasted finish removes is cover that no longer exists. A unit detailed with the code minimum cover to the form face and then blasted to a medium texture has less cover than the code requires, which is why the cover is measured to the finished surface and why the finish is settled before the reinforcement is detailed. {note}
−### In coastal exposure within one mile of saltwater, embedded connection hardware shall be stainless steel — Type 304 minimum, Type 316 where specified — conforming to ASTM A276/A276M or ASTM A666.
+## Where the cover required at the finished surface cannot be achieved within the unit thickness, the reinforcement at that surface shall be galvanized, stainless, or fiber-reinforced polymer, and the precast engineer shall state the cover provided on the shop drawings.
−## Why bare or thin-cover embeds fail. {note}
+## Reinforcement, lifting inserts, and wythe connectors shall be held at the position shown on the shop drawings by supports that leave no mark, rust stain, or shadow on a finished face.
−## Uncovered or thin-cover carbon-steel embeds in an exterior panel corrode, and the expanding corrosion product spalls the concrete face — a visible and progressive defect. The default is galvanized A36 for interior or protected locations and stainless for exposed exterior; specifying bare carbon steel at the face is an error. {note}
+## Steel bar chairs and tie wire ends at a finished face telegraph through as rust spots within the first year, and no patch matches them. Plastic-tipped or stainless supports at finished faces, and tie wire turned away from them, are the production disciplines that prevent it. {note}
−## Embed corrosion protection. {note}
+# Connection Hardware and Embedded Items {toc}
−## The corrosion protection of embedded hardware is recorded below and is driven by the service exposure selected earlier. Shop application of these coatings is governed by [[sync/shop-painting-and-galvanizing]] and [[sync/structural-steel-connections]]. {note}
+## Embedded plates, angles, and inserts of carbon steel shall conform to ASTM A36/A36M, and bolts shall conform to ASTM A307 or ASTM F3125/F3125M as the connection design requires.
−## The corrosion protection for embedded connection hardware shall be specified consistent with the service exposure selected for the panel.
+## Stainless steel hardware shall conform to ASTM A276/A276M or ASTM A666, Type 304 or Type 316.
+## Connection hardware embedded in the units and the loose connection material that joins them to the structure shall be protected against corrosion by the system indicated in the datasheet.
+
```datasheet
−label: Embed Corrosion Protection
−type: radio
+label: Connection Hardware Corrosion Protection
+type: select
options:
− - Galvanized carbon steel (interior / protected)
− - Galvanized carbon steel (exterior)
− - Stainless steel Type 304
− - Stainless steel Type 316 (coastal)
−default: Galvanized carbon steel (exterior)
+ - "Shop-primed carbon steel"
+ - "Hot-dip galvanized carbon steel, ASTM A123/A123M and ASTM A153/A153M"
+ - "Stainless steel, Type 304"
+ - "Stainless steel, Type 316"
+default: "Hot-dip galvanized carbon steel, ASTM A123/A123M and ASTM A153/A153M"
```
−### Non-shrink grout at bearing pads and connection pockets shall conform to ASTM C1107/C1107M.
+## A primed embed is protected until the first field weld burns the primer off, and it is the choice where every connection is inside a conditioned, dry wall cavity and the primer is restored after welding. Galvanizing survives the cavity's dampness and most of the welding, with the welds repaired, and it is the protection most exterior cladding connections carry. Type 304 stainless removes the repair-after-welding step and resists the moisture in an exterior cavity indefinitely; Type 316 adds resistance to chloride, which is the difference on a coastal site or at a connection reached by deicing salt. Stainless is welded to a carbon steel frame through a transition that [[sync/welding-requirements]] governs, and the cost is several times that of galvanized. {note}
−# Panel Construction {toc}
+## Connection hardware in units assigned corrosion-protection class C2 shall be stainless steel.
−## Panel cross-section. {note}
+## Connection hardware exposed to view in the finished work, and hardware within 1 in. of a finished face, shall be stainless steel.
−## The panel cross-section determines weight, thermal performance, and connection design. A thin-shell face on grey backup is the most common cladding section; insulated sandwich panels integrate continuous insulation into the cladding; solid panels are used where thickness is not a concern. {note}
+## Galvanized hardware damaged by welding or handling shall be repaired in accordance with ASTM A780/A780M before the connection is concealed.
−## The panel cross-section shall be specified to establish the panel's weight, thermal performance, and connection design.
+## Carbon steel hardware shall be isolated from stainless steel hardware and from aluminum by a non-conductive separator wherever the two would otherwise touch.
+## The plates, anchor rods, and inserts cast into the supporting structure to receive the panel connections shall be furnished by the party indicated in the datasheet.
+
```datasheet
−label: Panel Cross-Section
+label: Embedded Items in the Supporting Structure Furnished By
type: radio
options:
− - Thin-shell face on backup concrete
− - Solid single-mix panel
− - Insulated sandwich (face wythe + insulation + backup wythe)
−default: Thin-shell face on backup concrete
+ - "Precast producer, delivered to the trade placing the structure with a placement drawing"
+ - "Trade placing the structure, fabricated to the precast producer's details"
+default: "Precast producer, delivered to the trade placing the structure with a placement drawing"
```
−### Thin-shell face panels with normal reinforcement shall have a minimum face-wythe thickness of 3-1/2 in. per PCI MNL-117.
+## The producer furnishing the embeds is the common arrangement because the embed and the hardware it mates with are then one design, one material, and one coating; the trade placing the structure fabricating them fits a project where the structure is placed before the precast contract is let. Under either arrangement, the trade placing the structure sets them, under [[sync/cast-in-place-concrete]] and [[sync/concrete-accessories]] for a concrete frame and [[sync/structural-steel-framing]] for a steel frame, and the precast producer surveys them before erection. {note}
−## Reduced thickness with stainless reinforcement. {note}
+## Bearing pads at gravity connections shall be of the material, durometer, and size the precast engineer determines, and no unit shall bear concrete on concrete or concrete on steel without a pad or a grout bed.
−## A 3 in. face wythe is achievable only with stainless reinforcement at reduced cover and only by specific project approval; the standard minimum for normally reinforced thin shells remains 3-1/2 in. {note}
+## Non-shrink grout at bearing connections shall conform to ASTM C1107/C1107M and shall be placed in accordance with [[sync/non-shrink-grout]].
−### Insulated sandwich panels shall have a face wythe of at least 3-1/2 in., a continuous rigid insulation layer, and a structural backup wythe of at least 3 in.
+# Surface Finish {toc}
−## Panel thickness selection. {note}
+## Finish Treatment {toc}
−## The nominal panel thickness is recorded below for weight and connection sizing. Thin-shell cladding panels typically finish at a total of 5 in. to 7 in. including backup; sandwich panels are thicker by the insulation layer. {note}
+### The finished faces of the units shall receive the treatment indicated in the datasheet, and the treatment shall be applied to every face visible in the completed work, including returns, reveals, soffits, and exposed edges.
−## The nominal panel thickness shall be specified for weight and connection sizing.
−
```datasheet
−label: Nominal Panel Thickness
−type: range
−min: 3.5
−max: 10
−step: 0.5
−default: 6
−unit: in.
+label: Surface Finish Treatment
+type: select
+options:
+ - "As-cast against a smooth form"
+ - "Form liner texture"
+ - "Sandblasted"
+ - "Acid etched"
+ - "Exposed aggregate by surface retarder"
+ - "Bushhammered"
+ - "Honed"
+ - "Polished"
```
+### An as-cast face shows every bug hole, form joint, and color mottle the form leaves, which makes it the least forgiving finish and the one that most needs the mockup to set a realistic standard; it costs nothing beyond the form. A form liner casts a texture or relief into the face and hides much of the mottling, at the cost of the liner and the draft it needs to strip, and the liner joints must be set out so that they fall at reveals. Sandblasting removes the surface paste by abrasion to a matte texture whose depth is set by the blast, and it is the most common treatment because it is uniform, repairable, and forgiving of minor form defects. Acid etching dissolves a thin skin of paste to expose the sand and leave a fine, even texture that does not change the color as much as blasting; it demands careful neutralization and it is not suited to calcareous aggregate, which the acid attacks. Retarder exposure washes unhydrated paste off the form face to reveal the coarse aggregate at a controllable depth, and it is the finish that shows the aggregate itself as the color. Bushhammering fractures the surface mechanically to a rough, deep texture, the most labor-intensive treatment and the only one that reads as rough stone. Honing grinds the face flat to a matte surface that shows the aggregate in cross section, and polishing continues the grinding to a reflective surface; both need a dense, void-free face mix and a hard aggregate, and both are the most costly treatments per square foot. {note}
+
+### Where the treatment exposes the aggregate, the depth of exposure shall be as indicated in the datasheet.
+
```datasheet
−label: Panel Self-Weight (design)
−type: range
−min: 40
−max: 100
−step: 5
−default: 80
−unit: psf
+label: Depth of Exposure
+type: radio
+options:
+ - "Light, surface paste removed without exposing coarse aggregate"
+ - "Medium, coarse aggregate exposed to about one third of its diameter"
+ - "Deep, coarse aggregate exposed to about one half of its diameter"
```
−## Panel self-weight. {note}
+### A light exposure shows the color of the paste and sand and is the most uniform; a medium exposure shows the coarse aggregate as the dominant color, and it is where a selected facing aggregate earns its cost; a deep exposure shows the aggregate in relief and is the roughest and most costly, and it removes the most cover. {note}
−## The self-weight below is used for crane sizing and gravity-connection design. Solid architectural panels typically weigh 75–90 psf; insulated sandwich panels 45–65 psf. The lighter sandwich weight is one of its advantages. {note}
+### Where a form liner is selected, the liner pattern, its depth, and the layout of its joints shall be as indicated on [[drawing: the reveal and profile details]], and the liner joints shall fall at reveals or at panel edges.
−# Surface Finish {toc}
+### Where a surface retarder is used, it shall be applied uniformly to the form face at the rate the mockup was produced with, and the exposed face shall be washed at the time that reproduces the accepted depth.
−## Finish treatment defines the architectural character. {note}
+### Where an acid etch is used, the surface shall be neutralized and rinsed until free of residual acid, and the runoff shall be contained so that it does not reach any finished face below.
−## The exposed face may be left as cast, cast against a form liner for pattern or texture, or mechanically and chemically treated after stripping to expose aggregate and modulate color depth. Sandblasting, acid etching, bushhammering, retarder-wash exposed aggregate, polishing, and honing each reveal the aggregate to a different degree and read differently in raking light. Combination treatments are common. Every finish is approved only against the accepted mockup. {note}
+### Blasting, etching, washing, and grinding shall be carried uniformly to the edges of each face and around every reveal and return, so that the depth and texture do not change within a face.
−### The exposed face finish shall match the accepted finish sample and mockup in texture, aggregate exposure, and color depth.
+### The treated surface shall match the accepted mockup when judged at the finish acceptance viewing distance.
+## Applied Facings {toc}
+
+### The units shall be faced as indicated in the datasheet.
+
```datasheet
−label: Surface Finish Treatment
+label: Applied Facing
type: select
options:
− - As-cast smooth
− - Form liner (rubber / urethane / wood-grain / custom)
− - Light sandblast
− - Medium sandblast
− - Heavy sandblast
− - Light acid etch
− - Medium acid etch
− - Heavy acid etch
− - Bushhammer
− - Exposed aggregate (retarder wash)
− - Polished
− - Honed
−default: Light sandblast
+ - "None"
+ - "Thin brick cast into the face"
+ - "Natural stone veneer anchored to the unit"
+ - "Ceramic or porcelain tile cast into the face"
+default: "None"
```
−## Finish treatment. {note}
+### Thin brick cast into the face gives a brick facade with the panel's erection speed and without the shelf angles, ties, and cavity of anchored masonry; the brick is set in a form liner that fixes the joint pattern, and the joints are the concrete itself, so the face reads as brick at the viewing distance and as a precast panel at the corner unless the return is also bricked. Stone veneer anchored to the unit gives a stone facade in large pieces set at the plant, with the stone isolated from the concrete by a bond breaker and held by stainless anchors so that the two can move independently; its weight and the anchor design belong to the precast engineer. Tile cast into the face behaves like thin brick with a thinner unit and a glazed surface, and it is the least common of the three. {note}
−## The selected finish treatment is recorded below. As-cast and light-sandblast finishes are the most common production choices; deeper exposures and polishing carry cost and lead-time premiums and are reserved for feature surfaces. {note}
+### Thin brick shall conform to ASTM C1088, Grade Exterior, and shall be set in a form liner that fixes the brick spacing and holds the brick face against the form.
−### Where a form liner is used, the liner pattern, draft, and joint layout shall be shown on the shop drawings and shall match the accepted sample.
+### Natural stone veneer shall conform to ASTM C503/C503M, ASTM C568/C568M, or ASTM C615/C615M for its type, shall be separated from the concrete by a bond breaker, and shall be anchored to the unit with stainless steel anchors designed by the precast engineer in accordance with ASTM C1242.
−## Color acceptance. {note}
+### The joints between thin brick or tile shall be filled by the face mix as the unit is cast, and the finished joint shall match the accepted mockup in profile, color, and depth.
−## Color shall be judged against the approved mockup under north-sky daylight at a viewing distance of about 10 ft. Judging color at arm's length or under artificial light produces rejections that would never be visible on the building.
+### Facing units shall be from a single production run for the duration of the project, and the producer shall furnish the facing sample and the mockup from that run.
−### Finished color shall be accepted by comparison to the approved mockup under north-sky daylight at a viewing distance of 10 ft, and shall fall within any accepted range panels.
+## Surface Sealer {toc}
−# Tolerances {toc}
+### The finished faces shall receive the sealer indicated in the datasheet, applied after erection, patching, and cleaning are complete and accepted.
−## Product and erection tolerances are distinct. {note}
−
−## Product tolerances govern the dimensions of the cast unit at the plant; erection tolerances govern its installed position on the building. Joint width design must absorb both. PCI MNL-117 sets the architectural product tolerances and PCI 135-24 (and the superseded MNL-135) set erection tolerances. Specifying tolerances tighter than these without written confirmation from the producer that they are achievable drives cost premiums and RFIs — a 1/16 in. tolerance on a large panel is not a production reality. {note}
−
−### Product and erection tolerances shall conform to PCI MNL-117 and the current PCI tolerance standard unless tighter project-specific tolerances are confirmed achievable in writing by the producer.
−
```datasheet
−label: Tolerance Class
−type: radio
+label: Surface Sealer
+type: select
options:
− - Standard PCI MNL-117 architectural tolerances
− - Project-specific tighter tolerances (producer-confirmed)
−default: Standard PCI MNL-117 architectural tolerances
+ - "None"
+ - "Penetrating silane or siloxane water repellent"
+ - "Film-forming clear acrylic sealer"
```
−## PCI 135-24 adoption status. {note}
+### An unsealed face weathers as concrete does, darkening where water runs and lightening where it dries, which is the appearance many architectural precast facades are designed for. A penetrating silane or siloxane repellent leaves the surface appearance and vapor permeance unchanged while reducing water absorption and the dirt and efflorescence that come with it, and it is reapplied on an interval of several years. A film-forming acrylic changes the color and sheen of the face, which must be shown on the mockup, resists graffiti and staining better than a penetrant, and can trap moisture behind the film on a face that gets wet from behind. {note}
−## PCI 135-24 is a 2024 tolerance standard in public comment as of this writing. Confirm whether it has been formally adopted before citing it as mandatory; until then it is informative and MNL-135 / MNL-117 tolerances govern. {note}
+### The sealer shall be applied to the mockup before the mockup is accepted, so that the accepted appearance is the sealed appearance.
−### Flat-panel face-dimension variation shall not exceed ±1/8 in. on panels up to 10 ft and ±3/16 in. on panels 10 ft to 20 ft.
+### The sealer shall be compatible with the joint sealant specified in [[sync/joint-sealants]], and the sealer manufacturer shall confirm in writing that it does not impair sealant adhesion where the two meet.
−### Panel thickness shall be within ±3/16 in., and bow or warp shall not exceed 1/8 in. per 10 ft of length, with a maximum of 3/8 in.
+# Panel Joints {toc}
−### Installed panels shall be plumb within ±1/4 in. per story, not exceeding 1 in. over the full building height.
+## The nominal width of the joints between units shall be as indicated in the datasheet.
−### Installed joint width shall be within ±1/4 in. of the design dimension.
+```datasheet
+label: Nominal Joint Width Between Units
+type: range
+unit: in
+options:
+ min: 0.375
+ max: 1.5
+ setpoints: [0.375, 0.5, 0.625, 0.75, 1, 1.25, 1.5]
+default: 0.75
+```
−## Tolerance class. {note}
+## The joint has to absorb the product tolerance of both units, the erection tolerance, and the movement the sealant must take in service, and still leave a sealant bead within the width-to-depth ratio the sealant needs. Three quarters of an inch is the width that does this for most units up to about 30 ft, and it is what PCI MNL-122 points to as the practical minimum; a narrower joint is achievable on small trim units set to a tight tolerance, and a wider joint is needed on long units, on units with a large thermal movement, or where a lower-movement sealant is selected. The joint width is fixed when the units are cast and cannot be changed afterward. {note}
−## The applicable tolerance set is recorded below. Standard PCI architectural tolerances are the default; tighter tolerances are recorded only when the producer has confirmed them. {note}
+## The joint width shall not be less than the width required by the sealant's movement capability under [[sync/joint-sealants]] for the calculated movement at the joint.
−# Connections {toc}
+## The joints shall be sealed as indicated in the datasheet.
−## Connection design is the leading cause of panel distress. {note}
+```datasheet
+label: Joint Seal Configuration
+type: radio
+options:
+ - "Single-stage joint sealed at the exterior face"
+ - "Two-stage joint with an inner air seal and an outer rain seal, drained between them"
+default: "Single-stage joint sealed at the exterior face"
+```
−## Each panel hangs from a small number of connections that must resist gravity, wind, seismic, and thermal loads while accommodating fabrication and erection misalignment. The connection set is conventionally divided into gravity (bearing) connections, usually at the bottom of the panel, and lateral (tieback) connections that resist out-of-plane wind and seismic load and permit in-plane movement. Under-designed or under-detailed connections are the leading cause of cladding distress, which is why sealed delegated-design calculations are mandatory. {note}
+## A single exterior seal is the convention, and it works where the seal is maintained; a two-stage joint puts the air seal at the inside face where it stays dry and lets the outer seal be a rain screen that drains, so that a failed outer seal does not become a leak, at the cost of a second bead of sealant that cannot be inspected after erection and of a drained cavity that must be flashed out at the base of each panel run. {note}
−### Connection hardware shall be designed under delegated design and supported by calculations sealed by a professional engineer registered in the project jurisdiction.
+## The sealant, its backing, and its installation are specified in [[sync/joint-sealants]], and the joint faces of the units shall be finished to the condition that standard requires for sealant adhesion. {note}
−### Gravity connections shall carry the full panel self-weight; lateral connections shall resist out-of-plane wind and seismic load while permitting in-plane thermal and seismic movement.
+## Where a form-release agent, a surface retarder, or a sealer reaches a joint face, the joint face shall be cleaned to the condition the sealant manufacturer requires before the sealant is installed.
−### Connections shall provide three-axis field adjustment by slotted holes, shims, or equivalent means to absorb fabrication and erection tolerance.
+## The air barrier plane shall be continuous across the joints and at the perimeter of the units, by the sealant joint in a single-stage joint or by the inner seal in a two-stage joint, and its transition to the adjoining air barrier shall be as detailed under [[sync/air-barriers]].
−## Why adjustability is required. {note}
+## Joints between units shall align with the reveal pattern, with the window and curtain wall mullions they meet, and with the expansion and seismic separation joints of the structure.
−## With a panel fabrication tolerance and an erection tolerance both on the order of ±1/4 in., a connection with no adjustment cannot be set to the design joint line. Slotted holes, shim plates, and adjustable inserts give the erector the three-axis range needed to true the panel before the connection is locked. {note}
+# Tolerances {toc}
−## Connection material. {note}
+## The units shall be fabricated and erected within the tolerances indicated in the datasheet.
−## Connection material follows the same corrosion logic as the embeds it joins: galvanized carbon steel in protected service, stainless in exposed exterior, and Type 316 stainless in coastal exposure. Field welding of connection assemblies is governed by AWS D1.1 and coordinated with [[sync/structural-steel-connections]] and [[sync/miscellaneous-metals]]. {note}
−
−## The connection material shall be specified consistent with the corrosion protection selected for the embedded hardware it joins.
−
```datasheet
−label: Connection Material
+label: Tolerance Basis
type: radio
options:
− - Carbon steel, galvanized
− - Stainless steel Type 304
− - Stainless steel Type 316 (coastal)
−default: Carbon steel, galvanized
+ - "Product tolerances of PCI MNL-117 and erection tolerances of PCI MNL-135"
+ - "Tighter project tolerances scheduled in the contract documents, confirmed achievable by the producer in writing before bid"
+default: "Product tolerances of PCI MNL-117 and erection tolerances of PCI MNL-135"
```
−## Seismic ductility. {note}
+## The PCI tolerances are the ones a certified plant and a certified erector are audited against, and they are the basis every producer prices. A tighter tolerance is achievable on a specific unit with a specific form and a specific erection method, which is why it is confirmed by the producer before bid rather than imposed afterward; a tolerance tighter than the producer can hold becomes a schedule of rejected units. {note}
−## In higher Seismic Design Categories the connections must accommodate story drift without brittle failure. The seismic category below sets the ductility and detailing demand on the connection design under ASCE 7 Chapter 13 and ACI 318. {note}
+## Product tolerances shall be measured at the plant before shipment, and a unit outside the product tolerance shall not be shipped without the Engineer of Record's written acceptance.
−## The seismic design category shall be specified to establish the ductility and detailing demand on the connection design.
+## Erection tolerances shall be measured against the building grid and the benchmark elevations, not against the adjoining unit, so that error does not accumulate along a run.
−```datasheet
−label: Seismic Design Category
−type: select
−options:
− - A
− - B
− - C
− - D
− - E
− - F
−default: C
−```
+## The joint width between erected units shall be within the erection tolerance of the nominal joint width, and the face offset between adjoining units at a joint shall be within the PCI MNL-135 limit for architectural panels.
−### Field welds at connections shall conform to AWS D1.1 and shall be made by qualified welders.
+## Where the supporting structure is out of tolerance, the Contractor shall report the condition to the Engineer of Record before any unit is set against it, and the connection adjustment shall not be used to absorb structural error beyond the range the precast engineer designed.
−# Joints {toc}
+## Every connection carries an adjustment range so that the erector can true the unit to the joint line despite the product and erection tolerances; a frame that is itself out of plumb consumes that range before the unit is ever set, and a connection forced to the end of its slot has no adjustment left and no clearance. The survey of the structure before erection is where this is found. {note}
−## Joint width must absorb tolerance, not fight it.
+# Fabrication and Plant Quality Control {toc}
−## The face joint between panels must be wide enough to absorb the sum of panel fabrication tolerance and erection tolerance and still leave a sealant joint that can move. A design joint that is too narrow leaves no room for the panels' real positions, forces field grinding, and overstrains the sealant. For cladding panels a minimum design joint of about 3/4 in. is typical, widening to 1 in. on taller panels. The joint width must be confirmed before bid, because it cannot be changed after the panels are cast. {note}
+## Forms shall be constructed to hold the product tolerances for the number of casting cycles the project requires, and form faces for finished surfaces shall be free of defects that would reproduce in the face.
−### The design face-joint width shall be a minimum of 3/4 in. for panels up to 12 ft and 1 in. for panels 12 ft to 20 ft, and shall be confirmed before fabrication.
+## Form-release agent shall be compatible with the finish treatment and the sealer, shall not stain the face, and shall be the agent the mockup was produced with.
−```datasheet
−label: Design Face-Joint Width
−type: range
−min: 0.5
−max: 1.5
−step: 0.125
−default: 0.75
−unit: in.
−```
+## Concrete shall be placed and consolidated so that the finished face is free of honeycombing and of surface voids larger than the accepted mockup shows.
−### Backer rod shall be sized at approximately 1.25 times the joint width and installed to the depth required by the sealant manufacturer.
+## Units shall be cured by the method the producer's quality control program states, and the curing method and duration shall be the same for every unit of a given finish.
−## Sealant is delegated. {note}
+## A change in curing between units changes their color. Steam-cured and moist-cured units of the same mix differ visibly in shade, and so do units stripped at different ages, which is why curing is held constant across a finish rather than varied with the production schedule. {note}
−## This standard sets the joint geometry, backer-rod sizing, and bond-breaker requirement; the sealant product, conforming to ASTM C920, and its installation are selected and specified under [[sync/joint-sealants]]. Coordinating the two is essential — the joint width set here is an input the sealant standard depends on. {note}
+## The producer shall cast and test specimens for compressive strength in accordance with ASTM C31/C31M and ASTM C39/C39M, at not less than one set per face mix and one set per backup mix for each day of production, and air content shall be determined in accordance with ASTM C231/C231M at the same frequency for mixes assigned a freeze-thaw class other than F0.
−### Panel joints shall receive a bond breaker or closed-cell backer rod so the sealant bonds only to the two panel faces.
+## Every unit shall be inspected at the plant against the accepted mockup for finish, color, and texture, and against the shop drawings for dimensions, hardware position, and reinforcement cover, and the inspection shall be recorded by unit mark before the unit is shipped.
−## Coordination of reveals and openings. {note}
+## A unit that does not match the accepted mockup shall be rejected at the plant, or repaired at the plant and re-inspected, and a repaired unit shall be marked as repaired in the inspection record.
−## Reveal lines, window-opening locations, and joint patterns locked into the precast shop drawings must match the storefront and curtain-wall shop drawings before any panel is cast. Changes after fabrication are extremely costly, so the precast layout shall be coordinated with the glazing trades during shop-drawing review. This is the interface with [[sync/glazed-curtain-walls]] and [[sync/aluminum-entrances-and-storefronts]]. {note}
+## Each unit shall be marked with its mark number, casting date, and orientation for handling, in a location that is concealed in the completed work.
−### Precast panel elevations, reveals, and opening locations shall be coordinated with and confirmed against the curtain-wall, storefront, and window shop drawings before fabrication.
+# Erection {toc}
−# Installation {toc}
+## The Contractor shall survey the embedded items and the supporting structure against the erection drawings before erection begins, and shall report every embed outside its placement tolerance to the Engineer of Record.
−## Erection sequence and connection. {note}
+## The units shall be erected in the sequence shown on the erection drawings, and no unit shall be set out of sequence without the precast engineer's written acceptance.
−## Panels are set by crane to the erection drawings, aligned within tolerance using the connection adjustment, then permanently connected and grouted. Bearing pads at gravity connections distribute load and prevent point bearing on the concrete. The erector works to the panel marks and connection assignments on the approved erection drawings. {note}
+## Each unit shall be set on its bearing pads or grout bed, aligned to the joint lines within the erection tolerance, and connected at every connection shown for it before the crane is released from the unit.
−### Panels shall be erected in the sequence shown on the approved erection drawings.
+## Temporary bracing or a partial connection shall not be relied on to hold a unit after the crane is released unless the precast engineer has designed the temporary condition and shown it on the erection drawings.
−### Panels shall be aligned to the design joint lines within the specified erection tolerance before connections are permanently fixed.
+## Field welds shall be made under the procedures of [[sync/welding-requirements]], and welding near a finished face shall be shielded so that spatter and heat do not mark the face.
−### Gravity connections shall bear on the bearing pads shown on the connection details, and non-shrink grout shall be placed where detailed.
+## Bolted connections shall be tightened to the condition the precast engineer specifies, and slotted connections intended to slide shall be left free to do so after the unit is set.
−### Field-welded and bolted connections shall be completed and inspected before the supporting crane is released from the panel.
+## The connection that is meant to release the panel from frame movement is the one most often locked solid in the field, by a weld across a slot or a bolt tightened on a connection designed to slide. The erection drawings state which connections are fixed and which are released, and the special inspector checks the released ones as closely as the fixed ones. {note}
−## Field patching. {note}
+## Grout at bearing connections shall be placed after the unit is aligned and connected, and the unit shall not be loaded by the units above it until the grout has reached the strength the precast engineer requires.
−## Minor surface defects and connection-pocket fills are patched in the field using a mix that matches the accepted finish in color and texture. A patch that does not match is itself a defect; patches are evaluated against the same mockup and daylight viewing standard as the panels. {note}
+## Erected units shall be protected from damage, staining, and weld spatter by the following trades until the work is accepted, and damage caused by another trade shall be repaired at the expense of the party causing it.
−### Field patches shall be made with a patching mix matching the accepted face finish in color and texture, and shall be evaluated against the approved mockup.
+# Field Repair, Patching, and Cleaning {toc}
−### Damaged units whose defects cannot be patched to match the accepted finish shall be rejected and replaced.
+## The Contractor shall report every chipped, spalled, cracked, stained, or mismatched unit to the Engineer of Record before any repair begins, and the Engineer of Record shall make the initial determination whether the unit is repaired or replaced.
−## Cleaning. {note}
+## Repairs to finished faces shall be made with a patching mix prepared from the same cement, aggregate, and pigment as the face mix, adjusted by trial so that the cured patch matches the adjoining face at the finish acceptance viewing distance.
−## Panels are cleaned after erection and patching to a uniform appearance. Cleaning agents and methods shall not etch, discolor, or alter the accepted finish; aggressive acids that would change the surface character are prohibited.
+## A patch is judged against the same mockup and at the same viewing distance as the unit, and a patch that does not match is a defect in its own right. The constituents of the face mix are retained for this reason, and a patch that is mixed from a different cement or a different sand will never match however carefully it is proportioned. {note}
−### Installed panels shall be cleaned to a uniform appearance using methods that do not alter the accepted finish.
+## A repaired unit shall be treated after patching so that the patch carries the same finish treatment as the face around it.
−# Delivery, Storage, and Handling {toc}
+## Cracks that the precast engineer determines affect the structural adequacy of the unit or the protection of its reinforcement shall be cause for rejection of the unit, and the unit shall be replaced at the Contractor's expense.
−## Why shipping protection is specified. {note}
+## A unit whose face cannot be repaired to match the accepted mockup shall be replaced, and the replacement unit shall be accepted against the mockup as a production unit is.
−## A finished panel face shipped face-down, stacked without edge blocking, or handled by the face develops chips and surface damage that only become visible after installation, when replacement is most expensive. A shipping, storage, and handling protection plan is required, and panels shall be supported and separated to protect the finished face throughout transport and storage. {note}
+## After erection, patching, and sealant installation, the finished faces shall be cleaned by the method the producer's quality control program states, using water and a cleaning agent that does not etch, bleach, or discolor the face, and no acid cleaning shall be used on a face containing calcareous aggregate or thin brick with a glazed or sanded face.
−### Panels shall be shipped, stored, and handled in accordance with the approved protection plan.
+## A cleaning method shall be demonstrated on the mockup or on an inconspicuous unit and accepted before it is used on the facade.
−### Finished faces shall be protected from contact, edge chipping, and staining during transport and storage by blocking, separation, and non-staining dunnage.
+## Cleaning runoff shall be kept off glazing, metal, and sealant below the area being cleaned, and the adjoining work shall be protected from it.
−### Lifting and handling shall use the lift points and rigging shown on the producer's handling drawings.
+# Delivery, Storage, and Handling {toc}
−# Warranty {toc}
+## Units shall be lifted only at the lifting inserts shown on the shop drawings, with the rigging the handling plan specifies, and never by a finished face or an exposed edge.
−## Warranty scope. {note}
+## Units shall be stored and shipped on supports at the points the handling plan shows, in the orientation it shows, with non-staining separators between units and with finished faces protected from contact.
−## The producer and installer warrant the panels and their installation against defects in materials, fabrication finish, and connection workmanship. The warranty does not cover sealant, which is warranted under [[sync/joint-sealants]], nor damage from building movement beyond the design loads. {note}
+## Units shall not be shipped until they have reached the strength the precast engineer requires for shipping.
−### The producer shall warrant the architectural precast units against defects in materials, finish, and fabrication for the warranty period stated below.
+## Units stored at the site shall be kept off the ground, drained, and covered against rain and construction dirt, and shall be stored so that the erection sequence can be followed without re-handling.
−### The installer shall warrant the erection and connection of the units against defective workmanship for the warranty period stated below.
+## A finished face that is set down on gravel, leaned on a steel column, or stacked against another unit without a separator picks up a chip or a stain that is invisible until the unit is on the building and the sun is on it, and the repair then happens from a lift. Every handling rule in this section exists to keep the face off anything harder or dirtier than the separator. {note}
+# Warranty {toc}
+
+## The Contractor shall warrant the units, their finish, and their erection against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.
+
```datasheet
label: Warranty Period
−type: radio
−options:
− - 1 year
− - 2 years
− - 5 years
−default: 2 years
+type: range
unit: years
+options:
+ min: 1
+ max: 5
+ setpoints: [1, 2, 3, 5]
+default: 1
```
−# Spare Parts {toc}
+## The warranty shall cover cracking, spalling, and delamination of the units, rust staining from reinforcement or hardware, failure of a connection or a wythe connector, debonding of an applied facing, and a change in color or texture beyond the accepted range that is attributable to materials or production.
−## Attic stock for future repair. {note}
+## Where the parties disagree on the cause of a defect claimed under the warranty, the Engineer of Record shall make the initial determination.
−## Because face mixes are batch-specific and color is matched to a mockup, a small stock of spare finish material and any specialty connection hardware is held so that future patching and panel repair can match the original work. The quantity is recorded below. {note}
+## Work repaired under the warranty shall carry a renewed warranty running from the date the repair is accepted, for the full original period or for the remainder of the original period, whichever ends later.
−### The producer shall deliver attic stock of face-mix materials and specialty connection hardware sufficient for future patching and repair, in the quantity stated below.
+## Weathering of the face within the accepted range, soiling, damage by other trades after acceptance, movement of the structure beyond the design basis, and the sealant in the joints, which is warranted under [[sync/joint-sealants]], are outside this warranty. {note}
+# Attic Stock {toc}
+
+## The producer shall furnish the attic stock indicated in the datasheet before the work is accepted, packaged, labeled by face mix and unit type, and delivered to the location the Owner designates.
+
```datasheet
−label: Attic Stock — Face-Mix and Hardware
−type: radio
+label: Attic Stock Furnished
+type: checkbox
options:
− - None
− - Patching kit only
− - Patching kit plus spare connection hardware
−default: Patching kit only
+ - "Patching materials for each face mix, with the batch proportions"
+ - "Facing units from the project production run, where an applied facing is selected"
+ - "Spare loose connection hardware of each type"
+default:
+ - "Patching materials for each face mix, with the batch proportions"
```
+
+## A repair made years after acceptance can match the face only if it is made from the same cement, sand, and pigment the face was cast from, and those materials are gone from the plant within a season. The patching stock, with the batch record from the closeout submittals, is what makes a future repair possible. {note}