HVAC Air Distribution Devices
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in HVAC Air Distribution Devices.
−---
−title: HVAC Air Distribution Devices
−category: Mechanical / Air Distribution
−toc_depth: 3
−description: >
− When to use: Room-side air distribution devices for commercial, institutional, and industrial HVAC systems — including supply diffusers (square/round, linear-slot, swirl, displacement), return grilles, exhaust grilles, transfer grilles, light-troffer-integrated diffusers, and security/correctional grilles. Covers materials (steel, aluminum, stainless), finishes, frame styles for lay-in/surface/plaster ceilings, opposed-blade dampers (OBDs), equalizers and scoops, and the performance metrics that govern occupant comfort and acoustic acceptability: throw at terminal velocities of 50/100/150 fpm, ADPI targets per ASHRAE Fundamentals, and NC ratings at design airflow per AHRI 885. Applies to new construction and major renovation projects where outlets and inlets are connected to a duct distribution system.
− Not intended for: Air terminal units (VAV, CV, and fan-powered boxes — see [[sync/air-terminal-units]]); duct construction, sealing, and leakage testing (see [[sync/hvac-ductwork]]); air-handling unit casing and coil sections (see [[sync/air-handling-units]]); testing, adjusting, and balancing of the completed air distribution system (see [[sync/testing-adjusting-and-balancing]]); laboratory and cleanroom outlets serving critical environments (which use this standard as a baseline but require application-specific modifications for unidirectional flow, integral HEPA housings, and pressure-cascade control); kitchen exhaust hoods and grease-laden exhaust terminations; smoke-control system relief and intake louvers; outdoor intake and exhaust louvers in building envelope penetrations; perforated radiant ceiling panels providing primary thermal exchange.
−---
−
−# Scope {toc}
−
−## This standard covers the selection, performance rating, materials, construction, and installation of room-side air distribution devices for HVAC systems in commercial and institutional buildings. {note}
−## Devices covered include supply diffusers of all common configurations (square plaque, round, perforated face, linear slot, swirl, displacement), return and exhaust grilles, transfer grilles, light-troffer-integrated diffusers, and security/correctional-grade grilles. {note}
−## Construction materials, finishes, frame styles for various ceiling systems, integral opposed-blade dampers (OBDs), equalizing grids, scoops, and other accessory provisions are addressed. {note}
−
−## Role of Air Distribution Devices {toc}
−
−### Air distribution devices are the visible end of the HVAC system and the interface between the conditioned air stream and the occupant. {note}
−### Properly selected devices deliver the design airflow at acceptable noise, distribute that airflow across the occupied zone without drafts or stagnation, and present a clean architectural appearance consistent with the ceiling system into which they are installed. {note}
−### Poorly selected or installed devices cause every category of occupant complaint that mechanical systems are blamed for: drafts, hot and cold spots, noise, condensation on the face, dust streaking on the ceiling, and visible architectural conflicts with the lighting and ceiling layout. {note}
−### Selection requires coordinated attention to airflow, throw, terminal velocity, room geometry, ceiling height, the location of occupants relative to the device, and the acoustic environment. {note}
−
−## Performance ratings shall conform to ANSI/ASHRAE 70 and to AHRI 885 as applicable.
−
−## Air diffusion performance for the occupied space shall be evaluated per the ADPI methodology described in ASHRAE Handbook — Fundamentals, Space Air Diffusion chapter.
−
−## Device selection shall be coordinated with the duct distribution system in [[sync/hvac-ductwork]], with upstream terminal units in [[sync/air-terminal-units]], with air-handling unit selection in [[sync/air-handling-units]], and with field testing and balancing in [[sync/testing-adjusting-and-balancing]].
−
−# Referenced Standards {toc}
−
−## Equipment, materials, and installation shall comply with the latest editions of the following standards adopted by the project jurisdiction.
−
−| Standard | Title |
−|----------|-------|
−| ANSI/ASHRAE 70 | Method of Testing for Rating the Performance of Air Outlets and Inlets |
−| ANSI/AHRI 885 | Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminals and Air Outlets |
−| ANSI/AHRI 880 | Performance Rating of Air Terminals (cross-reference for sound and pressure characterization of upstream terminal units only — not applicable to outlets) |
−| ASHRAE Handbook — Fundamentals | Space Air Diffusion chapter (ADPI methodology, throw, terminal velocity, room load criteria) |
−| ANSI/ASHRAE/IES 90.1 | Energy Standard for Buildings Except Low-Rise Residential Buildings (current adopted edition) |
−| NFPA 90A | Standard for the Installation of Air-Conditioning and Ventilating Systems |
−| ASTM E84 | Standard Test Method for Surface Burning Characteristics of Building Materials |
−| ASTM A653 | Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated by the Hot-Dip Process |
−| ASTM B209 | Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate |
−| ASTM A240 | Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip |
−| UL 555S | Standard for Smoke Dampers (applicable where security/blast/fire-rated grilles are required to include damper functionality) |
−| SMACNA HVAC Air Duct Leakage Test Manual | Referenced for duct interface only — does not govern outlet device construction |
−| ICC A117.1 / ADA Standards | Accessible and Usable Buildings and Facilities (clearance and projection limits for wall-mounted devices in accessible routes) |
−
−## Where a specific edition is referenced in contract documents or by the local building code, that edition shall govern.
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### The Contractor shall submit the following for the Engineer's review and return prior to procurement or installation of the corresponding devices.
−
−### No device shall be procured for installation until the associated submittal has been reviewed and returned with no outstanding engineering questions.
−
−### The Contractor shall submit the following action submittal deliverables {toc}
−- Product data sheets for each device type, including face dimensions, neck/throat dimensions, frame style, material, finish, listed pattern controllers or adjustable cores where provided, and integral accessories (OBD, equalizer, scoop)
−- Performance data tables or selection curves from the manufacturer showing, at the design neck velocity or face velocity for each tagged outlet: total airflow (cfm), throw to 50/100/150 fpm terminal velocities (in feet), neck total pressure (in. w.g.), and NC rating, all derived from testing per ASHRAE 70 and AHRI 885
−- ADPI calculation summary for each typical room type served, demonstrating that the selected outlet, located at the indicated position with the design airflow, achieves an ADPI of not less than the value specified for the room type
−- Finish samples or color chip data for each finish specified, including standard white, custom paint colors, and any anodized or special finishes
−- Frame style cross-section detail confirming compatibility with the ceiling system or wall construction shown on the architectural drawings, including the ceiling tile size and grid module for lay-in installations, the plaster ring detail for plaster ceilings, and the surface-mount frame detail for hard-lid ceilings
−- Schedule of devices keyed to the mechanical drawings and air outlet schedule, listing tag, model, size, neck/throat, finish, frame style, OBD requirement, and design airflow
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - "Product data — each device type"
− - "Performance data — throw at 50/100/150 fpm, NC, neck pressure"
− - "ADPI calculation summary for each room type"
− - "Finish samples or color chips"
− - "Frame style cross-section detail for each ceiling/wall type"
− - "Device schedule keyed to drawings"
−default: "Product data — each device type"
−```
−
−## Closeout Submittals {toc}
−
−### At substantial completion and before final acceptance of the air distribution system, the Contractor shall provide:
−
−- As-built device schedule reflecting any field substitutions, including the substituted manufacturer and the engineering review documentation for each substitution
−- Operation and maintenance instructions for removable cores, adjustable pattern controllers, and integral dampers, including the position-setting procedure established during balancing
−- TAB report sections for each device documenting the measured airflow at final balance, in coordination with [[sync/testing-adjusting-and-balancing]]
−- Warranty documentation from the manufacturer covering finish and material defects
−
−```datasheet
−label: Closeout Submittals Required
−type: checkbox
−options:
− - "As-built device schedule reflecting field substitutions"
− - "Operation and maintenance instructions for cores, controllers, and dampers"
− - "TAB report sections documenting measured airflow at final balance"
− - "Warranty documentation covering finish and material defects"
−default:
− - "As-built device schedule reflecting field substitutions"
− - "Operation and maintenance instructions for cores, controllers, and dampers"
− - "TAB report sections documenting measured airflow at final balance"
− - "Warranty documentation covering finish and material defects"
−```
−
−# Quality Assurance {toc}
−
−## Manufacturer Qualifications {toc}
−
−### Devices shall be manufactured by a company with a minimum of five years of continuous experience producing air distribution outlets and inlets for commercial HVAC service.
−
−### The manufacturer shall publish performance data derived from independent or accredited in-house testing per ASHRAE 70 and AHRI 885.
−
−### The manufacturer shall maintain a current published catalog covering the full range of devices supplied.
−
−### The manufacturer shall maintain a domestic stock of replacement cores and damper assemblies sufficient to support the project for a minimum of ten years after substantial completion.
−
−## Single-Source for Each Device Family {toc}
−
−### For each room type and each visible ceiling area, all devices of the same category shall be supplied by a single manufacturer to maintain consistent appearance, frame profile, and finish.
−
−### Mixing manufacturers within a continuous visible area produces visible variation in face pattern, border profile, and color match that is unacceptable and is a frequent source of punch-list items. {note}
−
−## Performance Certification {toc}
−
−### Published performance data shall be derived from testing in accordance with ANSI/ASHRAE 70.
−
−### Sound ratings shall be developed in accordance with AHRI 885.
−
−### The Contractor shall not substitute devices for which performance data are not derived from these procedures.
−
−### Manufacturer data sheets shall clearly identify the test standard applied.
−
−## Mock-Up {toc}
−
−### Where the project includes more than 50 devices of the same model in a continuous visible ceiling area, or where the Architect or Engineer specifies it, the Contractor shall install a mock-up of one device of each type, installed in the actual ceiling assembly with the proposed finish, before procuring the balance of the order.
−
−### The Architect and Engineer shall review the mock-up for finish match, frame fit, and visible appearance before the Contractor releases the full procurement.
−
−# Environmental and Service Conditions {toc}
−
−## Air distribution devices shall be selected for the environment in which they will operate.
−
−## Devices in normal interior conditioned spaces use standard steel or aluminum construction with painted or anodized finishes, while devices in showers, natatoriums, kitchens, and other high-humidity or corrosive environments require material selection appropriate to the service. {note}
−
−## Interior Conditioned Spaces {toc}
−
−### Steel or aluminum construction with the manufacturer's standard powder-coat finish is appropriate for normal interior office, classroom, retail, and similar occupancies.
−
−### The standard finish shall be matte white, off-white selected to match common acoustical ceiling tile colors.
−
−### Where the architect specifies a custom color, the manufacturer's color-match service shall be used.
−
−## High-Humidity and Wet Areas {toc}
−
−### In bathrooms with adjacent showers, in natatoriums and indoor pool areas, in kitchens, and in similar wet or high-humidity environments, devices shall be aluminum or stainless steel construction.
−
−### Standard steel devices with painted finishes corrode at the cut edges and at fastener penetrations under sustained moisture exposure, even when the visible face appears acceptable for the first few years of service. {note}
−
−## Corrosive Atmospheres {toc}
−
−### In laboratory exhaust applications, in spaces with chemical processing, and in indoor pools with chlorine-based water treatment, stainless steel (Type 316 preferred over Type 304 in chloride-rich environments) shall be specified.
−
−### Aluminum is acceptable in many corrosive applications but shall not be used where chloride or alkaline cleaning solutions contact the device.
−
−## Exterior and Outdoor Air Applications {toc}
−
−### Where intake or exhaust devices are installed at the exterior of the building, they shall be specifically rated for outdoor service with appropriate provisions for water shedding, insect screens, and the wind loads imposed at the device location.
−
−### Standard interior diffusers and grilles shall not be installed at exterior wall penetrations; outdoor service requires louvers or weather-rated grilles, which fall outside the scope of this standard.
−
−## Default Device Material Selection {toc}
−
−```datasheet
−label: Device Material — Default for this Project
−type: radio
−options:
− - "Steel, ASTM A653, with manufacturer's standard powder-coat finish (interior conditioned)"
− - "Extruded or formed aluminum, ASTM B209, anodized or powder-coated finish"
− - "Stainless steel, ASTM A240, Type 304 (wet areas)"
− - "Stainless steel, ASTM A240, Type 316 (corrosive/chloride environments)"
−default: "Steel, ASTM A653, with manufacturer's standard powder-coat finish (interior conditioned)"
−```
−
−# Performance Requirements {toc}
−
−## Airflow, Throw, and Terminal Velocity {toc}
−
−### The performance of a supply outlet is characterized by its airflow rate (cfm), by the throw to 50, 100, and 150 fpm terminal velocities, by the neck total pressure required to deliver that airflow (in. w.g.), and by the sound level produced at the design airflow (NC). {note}
−
−### All four characteristics shall be verified against published data for the selected device at the design conditions.
−
−### Throw to 100 fpm terminal velocity shall match the room geometry such that the 100 fpm boundary reaches approximately to the perimeter wall (or to the opposing diffuser's 100 fpm boundary in multi-diffuser rooms) at the ceiling level, with the supply jet falling into the occupied zone at velocities below 50 fpm.
−
−### Throw to 100 fpm terminal velocity is the dominant comfort metric for cooling-mode supply diffusers in occupied spaces; selecting a device only by neck size or by airflow without considering throw and NC is a leading cause of comfort and noise complaints. {note}
−
−### Design Throw Setpoints {toc}
−
−```datasheet
−label: Design Throw at 100 fpm Terminal Velocity
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 4
− max: 40
− setpoints: [4, 6, 8, 10, 12, 15, 18, 21, 25, 30, 35, 40]
−default: 12
−```
−
−```datasheet
−label: Design Throw at 50 fpm Terminal Velocity (for occupied-zone draft check)
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 6
− max: 60
− setpoints: [6, 8, 10, 12, 15, 18, 21, 25, 30, 40, 50, 60]
−default: 18
−```
−
−```datasheet
−label: Design Throw at 150 fpm Terminal Velocity (for jet attachment and perimeter washing)
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 3
− max: 25
− setpoints: [3, 4, 5, 6, 8, 10, 12, 15, 18, 21, 25]
−default: 8
−```
−
−### For heating-mode supply diffusers serving spaces with the supply air above the room temperature, the buoyancy of the warm jet works against the diffuser's downward throw. {note}
−
−### Where the same ceiling-mounted diffuser is used for both heating and cooling supply, the Engineer shall verify that the heating-mode throw is sufficient to reach the occupied zone; otherwise warm air will stratify at the ceiling and the occupied zone will remain cold.
−
−### For combined heating and cooling diffusers in spaces with ceilings above 12 ft, the design team shall verify heating performance with a separate calculation or shall use diffusers with adjustable pattern controllers (see Adjustable Pattern Controllers).
−
−### Throw-to-mounting-height ratios of 0.5 to 0.75 are typical for cooling-mode diffusers. {note}
−
−## Air Diffusion Performance Index (ADPI) {toc}
−
−### ADPI is the percentage of occupied-zone locations where the local effective draft temperature falls within the comfort envelope and is the consensus single-number metric for cooling-mode air diffusion quality. {note}
−
−### ADPI shall be calculated or estimated for each typical room type, with selection of throw and airflow tuned to achieve the target.
−
−### ADPI Target Selection {toc}
−
−```datasheet
−label: ADPI Target for Cooling Mode
−type: select
−unit: percent
−options:
− - "70% — minimum acceptable (lowest-cost spaces only)"
− - "80% — standard commercial target"
− - "85% — high-quality office and classroom"
− - "90% — premium quality, conference rooms and executive spaces"
−default: "80% — standard commercial target"
−```
−
−### ADPI targets above 90% generally require either careful pattern adjustment or higher diffuser counts than the minimum required by airflow alone. {note}
−
−### Where the design room load is high (above approximately 30 Btu/h/ft² sensible), achieving ADPI ≥ 80% with ceiling-mounted diffusers shall require careful attention to the ratio of throw to characteristic room length per ASHRAE Fundamentals; under-throwing such rooms produces stagnant occupied zones with poor mixing.
−
−## Noise Criterion (NC) {toc}
−
−### NC rating at the design airflow shall be selected based on the room's intended use.
−
−### NC shall be derived per AHRI 885, which addresses the conversion from manufacturer outlet sound power data (from ASHRAE 70 testing) to estimated sound pressure in the receiving room using a standardized room correction.
−
−### Bare manufacturer sound power numbers are not directly comparable to room NC without applying the room correction. {note}
−
−### NC Target Selection {toc}
−
−```datasheet
−label: NC Target at Design Airflow
−type: select
−options:
− - "NC 25 — concert halls, recording studios, executive offices"
− - "NC 30 — private offices, classrooms, conference rooms, hospitals"
− - "NC 35 — open offices, retail, restaurants, libraries"
− - "NC 40 — corridors, lobbies, light commercial"
− - "NC 45 — kitchens, mechanical/service areas, gymnasiums"
−default: "NC 35 — open offices, retail, restaurants, libraries"
−```
−
−### Each manufacturer applies a room correction to convert published outlet sound power into the room NC value shown in the published selection table, typically assuming a room with 10 dB of room absorption and the outlet at a specified distance from the receiver. {note}
−
−### For rooms with significantly different absorption (highly reverberant spaces like atria, lobbies with hard surfaces), the Engineer shall apply additional room correction per AHRI 885 where the published assumptions do not represent the actual application.
−
−### AHRI 885 Room Correction Method {toc}
−
−```datasheet
−label: AHRI 885 Room Correction Method
−type: radio
−options:
− - "Manufacturer's published NC at design airflow (standard room correction)"
− - "AHRI 885 calculation by Engineer using project room absorption and distance"
−default: "Manufacturer's published NC at design airflow (standard room correction)"
−```
−
−## Neck Pressure and System Resistance {toc}
−
−### The neck total pressure of the selected device at the design airflow is the resistance the device adds to the duct system and shall be included in the fan static pressure calculation for the system.
−
−### Devices with integral OBDs add additional pressure drop when the OBD is throttled; the Engineer shall account for the throttled OBD pressure drop in the duct design, not the full-open value.
−
−### Neck Total Pressure {toc}
−
−```datasheet
−label: Neck Total Pressure at Design Airflow
−type: range
−unit: in. w.g.
−options:
− min: 0.02
− max: 0.30
− step: 0.01
−default: 0.08
−```
−
−# Supply Diffusers — Types and Selection {toc}
−
−## Square and Rectangular Plaque Diffusers {toc}
−
−### Square and rectangular plaque diffusers discharge a horizontal jet in one, two, three, or four directions across the ceiling, with the supply air attaching to the ceiling surface by Coanda effect and decaying along the throw distance. {note}
−
−### The directional pattern is set at the factory or selected from a removable core; one- and two-way patterns are used where the diffuser is near a wall or corner and four-way patterns are used in open-area locations away from walls. {note}
−
−### Plaque Diffuser Discharge Pattern {toc}
−
−```datasheet
−label: Square/Rectangular Plaque Diffuser — Discharge Pattern
−type: radio
−options:
− - "1-way (against perimeter wall)"
− - "2-way opposite (between two walls)"
− - "2-way adjacent (corner installation)"
− - "3-way (one wall adjacent)"
− - "4-way (open area, no adjacent wall)"
−default: "4-way (open area, no adjacent wall)"
−```
−
−### Plaque diffusers are the standard for general cooling-mode supply in office, classroom, and retail spaces with ceilings of 8 to 14 ft. {note}
−
−### Plaque diffusers shall not be used for heating-mode supply where the horizontal discharge does not penetrate the warm ceiling layer; for heating-only spaces use a downward-projecting diffuser such as a swirl diffuser or a sidewall grille set to project downward.
−
−### Plaque Diffuser Face and Neck Sizes {toc}
−
−```datasheet
−label: Square/Rectangular Diffuser Face Size
−type: select
−unit: in
−drawing_ref: true
−options:
− - "6 × 6"
− - "9 × 9"
− - "12 × 12"
− - "15 × 15"
− - "18 × 18"
− - "24 × 24"
−default: "24 × 24"
−```
−
−```datasheet
−label: Square/Rectangular Diffuser Neck Size
−type: select
−unit: in
−drawing_ref: true
−options:
− - "6"
− - "8"
− - "10"
− - "12"
− - "14"
− - "16"
− - "18"
− - "20"
−default: "12"
−```
−
−## Round Ceiling Diffusers {toc}
−
−### Round ceiling diffusers provide a radial 360-degree discharge pattern and are used in open areas where a uniform horizontal throw in all directions is desired. {note}
−
−### Round diffusers shall not be installed close to walls (within one diffuser diameter) because the wall obstructs the radial pattern and produces stagnation on the wall side.
−
−### Round Diffuser Face Diameter {toc}
−
−```datasheet
−label: Round Diffuser Face Diameter
−type: select
−unit: in
−drawing_ref: true
−options:
− - "8"
− - "10"
− - "12"
− - "15"
− - "18"
− - "24"
−default: "12"
−```
−
−## Linear Slot Diffusers {toc}
−
−### Linear slot diffusers discharge a long, thin supply jet from a slot (or multiple parallel slots) extending along a continuous run, used to wash perimeter walls and glazing, at the edges of architectural soffits, and in open-plenum or exposed-ceiling applications where the linear form integrates with linear lighting fixtures. {note}
−
−### The number of slots per linear foot affects throw, neck pressure, and NC: more slots at the same airflow give higher throw and lower NC; fewer slots give the opposite. {note}
−
−### Slot pattern controllers (adjustable internal blades that bias the jet direction) shall be specified where the same linear slot must serve both heating and cooling modes — set to throw outward across the ceiling in cooling and downward into the occupied zone in heating.
−
−### Linear Slot Diffuser Selection {toc}
−
−```datasheet
−label: Linear Slot Diffuser — Number of Slots
−type: select
−options:
− - "1 slot"
− - "2 slots"
− - "3 slots"
− - "4 slots"
− - "6 slots"
− - "8 slots"
−default: "2 slots"
−```
−
−```datasheet
−label: Linear Slot Diffuser — Slot Width
−type: select
−unit: in
−options:
− - "1/2"
− - "3/4"
− - "1"
− - "1-1/4"
− - "1-1/2"
−default: "3/4"
−```
−
−```datasheet
−label: Linear Slot Diffuser — Section Length
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 2
− max: 20
− setpoints: [2, 3, 4, 5, 6, 8, 10, 12, 15, 20]
−default: 4
−```
−
−```datasheet
−label: Linear Slot Pattern Controller
−type: radio
−options:
− - "Fixed horizontal discharge (cooling only)"
− - "Field-adjustable pattern controller (combined heating and cooling)"
− - "Vertical (downward) discharge (heating-dominant or makeup-air)"
−default: "Field-adjustable pattern controller (combined heating and cooling)"
−```
−
−### End caps on continuous linear slot runs shall be coordinated with the architectural design, since exposed end caps are visible at the ends of each run and may interrupt a continuous architectural line.
−
−### Where multiple slot sections are joined to form a continuous run, the joints shall align with the architectural module and be sealed at the inactive (non-airflow) length to maintain visual continuity.
−
−## Swirl and Circular-Throw Diffusers {toc}
−
−### Swirl diffusers discharge a strong rotational supply jet that mixes rapidly with room air, producing high induction and a relatively short throw. {note}
−
−### Swirl diffusers are appropriate for spaces with high ceilings (above 12 ft) where conventional plaque diffusers would over-throw the room, and for cold supply or high-temperature-differential applications where rapid mixing is essential to avoid drafts at the occupied level. {note}
−
−### Swirl Diffuser Size {toc}
−
−```datasheet
−label: Swirl Diffuser Face Diameter or Size
−type: select
−unit: in
−drawing_ref: true
−options:
− - "12"
− - "15"
− - "18"
− - "24"
− - "30"
−default: "18"
−```
−
−## Displacement Diffusers {toc}
−
−### Displacement diffusers introduce conditioned supply air at low velocity (typically 50 to 80 fpm at the device face) near the floor, allowing the cool supply air to spread along the floor and rise by buoyancy as it picks up heat from occupants and equipment. {note}
−
−### Displacement systems can deliver superior air quality in the breathing zone with reduced fan power compared to overhead mixing systems, but require careful coordination with room layout, internal partitions, and heat sources. {note}
−
−### Displacement Diffuser Configuration {toc}
−
−```datasheet
−label: Displacement Diffuser Configuration
−type: select
−options:
− - "Not used on this project — overhead mixing system"
− - "Floor-mounted, half-round wall integrated"
− - "Floor-mounted, quarter-round corner integrated"
− - "Floor-mounted, free-standing column"
− - "Sidewall-mounted at low elevation"
−default: "Not used on this project — overhead mixing system"
−```
−
−### Displacement diffusers shall not be specified in rooms with cooling loads above approximately 30 Btu/h/ft² because the supply air temperature required to remove the load creates unacceptable cold-feet sensation at the supply jet.
−
−### Displacement is best applied to rooms with moderate loads, tall ceilings, and clear floor-to-return paths. {note}
−
−# Returns, Exhausts, and Transfer {toc}
−
−## Return Grilles {toc}
−
−### Return grilles collect air from the room for return to the air handler; because the suction zone of an inlet is small, return grille location is less critical for room air motion than supply diffuser location, but improper return location can short-circuit supply air directly back to the return without conditioning the occupied zone. {note}
−
−### Return Grille Style and Size {toc}
−
−```datasheet
−label: Return Grille Style
−type: radio
−options:
− - "Fixed louver — horizontal blades"
− - "Fixed louver — 45-degree deflection blades"
− - "Eggcrate — 1/2 in. × 1/2 in. cell"
− - "Eggcrate — 1/2 in. × 1 in. cell (general purpose)"
− - "Perforated face (matches supply diffuser appearance)"
−default: "Eggcrate — 1/2 in. × 1 in. cell (general purpose)"
−```
−
−```datasheet
−label: Return Grille Face Size
−type: select
−unit: in
−drawing_ref: true
−options:
− - "12 × 12"
− - "18 × 18"
− - "24 × 12"
− - "24 × 24"
− - "36 × 12"
− - "36 × 24"
− - "48 × 24"
−default: "24 × 24"
−```
−
−### Return grille face velocity shall be selected based on the NC target for the room and the proximity of the grille to occupied areas.
−
−### Face velocities of 400 to 500 fpm are typical for general office and classroom return grilles; lower face velocities (300 to 400 fpm) are appropriate for NC 30 rooms and quieter; higher face velocities (500 to 600 fpm) are acceptable in corridors and back-of-house areas. {note}
−
−### Face velocities above 700 fpm shall not be used because they produce audible noise and increased system static pressure.
−
−### Return Grille Face Velocity {toc}
−
−```datasheet
−label: Return Grille Face Velocity at Design Airflow
−type: range
−unit: fpm
−options:
− min: 200
− max: 700
− setpoints: [200, 300, 400, 500, 600, 700]
−default: 400
−```
−
−## Exhaust Grilles {toc}
−
−### Exhaust grilles serve restrooms, janitor closets, and other spaces from which contaminated air shall be removed without returning it to the supply system, typically constructed identically to return grilles but connected to a dedicated exhaust duct system. {note}
−
−### Where the exhaust duct conveys grease, moisture, or fumes that are corrosive, the grille shall match the duct material to avoid galvanic or corrosion incompatibility at the duct interface.
−
−### Exhaust Grille Style {toc}
−
−```datasheet
−label: Exhaust Grille Style
−type: radio
−options:
− - "Same as return grille style (general exhaust)"
− - "Louver-type with 1/2 in. blade spacing (toilet exhaust)"
− - "Eggcrate (general exhaust)"
− - "Stainless steel construction (corrosive exhaust)"
−default: "Eggcrate (general exhaust)"
−```
−
−## Transfer Grilles {toc}
−
−### Transfer grilles allow air to pass from one space to an adjacent space without dedicated ductwork, for example allowing supply air from an office to relieve into a return air corridor. {note}
−
−### Transfer grilles in fire-rated assemblies require fire dampers or shall not be installed in the rated assembly; the Contractor shall coordinate with the fire-rated assembly schedule on the architectural drawings to confirm that each transfer grille location does not penetrate a fire-rated assembly without appropriate fire-resistance provisions.
−
−### Transfer grilles shall be acoustically rated where they cross from a private office or conference room into a corridor or open area.
−
−### Uninsulated transfer grilles allow speech to pass directly between spaces and undermine the acoustic privacy of the originating space; acoustic transfer grilles include a baffled, lined plenum behind a louver face that absorbs speech-band sound while permitting airflow. {note}
−
−### Transfer Grille Type {toc}
−
−```datasheet
−label: Transfer Grille Type
−type: radio
−options:
− - "Standard louver — no acoustic treatment (corridor return paths)"
− - "Acoustically lined transfer (private office to corridor or conference room transfer)"
− - "Not used on this project"
−default: "Not used on this project"
−```
−
−# Frame Styles for Ceiling and Wall Systems {toc}
−
−## Lay-in Ceiling Frames (Suspended T-Bar Grid) {toc}
−
−### Lay-in frames are designed to drop into a standard suspended acoustical ceiling T-bar grid (typically 24 in. × 24 in. or 24 in. × 48 in. nominal modules), with the face panel at the full module dimension and the visible flange overlapping the T-bar flush with the surrounding ceiling tiles. {note}
−
−### Lay-in frames are the default for office, classroom, and corridor ceilings constructed with suspended acoustical tile. {note}
−
−### Lay-in Frame Ceiling Grid Module {toc}
−
−```datasheet
−label: Lay-in Frame — Ceiling Grid Module
−type: select
−unit: in
−options:
− - "24 × 24"
− - "24 × 48"
− - "Concealed grid (proprietary tile system)"
− - "Not applicable — non-lay-in ceiling"
−default: "24 × 24"
−```
−
−## Surface-Mount Frames (Hard-Lid Ceilings and Walls) {toc}
−
−### Surface-mount frames are installed on a finished surface (gypsum board ceiling, plaster ceiling, or wall) with a visible border flange screwed to the surface and a duct collar penetrating the surface behind the device. {note}
−
−### Surface-mount frames are used in hard-lid ceilings, in retail and hospitality where the suspended ceiling has been replaced by a finished hard surface, and at wall-mounted device locations. {note}
−
−### Surface-Mount Frame Surface Type {toc}
−
−```datasheet
−label: Surface-Mount Frame — Surface Type
−type: radio
−options:
− - "Painted gypsum board"
− - "Plaster"
− - "Finished wood or paneling"
− - "Concrete or masonry"
−default: "Painted gypsum board"
−```
−
−## Plaster (Mud-In) Frames {toc}
−
−### Plaster frames (also called mud-in or snap-in frames) are installed before the plaster or skim-coat finish is applied and are designed so that the plaster surface terminates flush with the device face, with no visible frame border. {note}
−
−### The mud-in result is a clean device face with no border interruption — preferred in high-end architectural plaster ceilings, in museum and gallery spaces, and in healthcare patient rooms where surface continuity supports cleanability. {note}
−
−### Plaster frames shall be coordinated with the plastering trade to ensure the rough opening is correctly sized and the frame is installed at the correct elevation before plaster work begins.
−
−### Plaster Frame Selection {toc}
−
−```datasheet
−label: Plaster Frame Required (Mud-In Style)
−type: radio
−options:
− - "Yes — coordinate with plastering trade"
− - "No — lay-in or surface-mount frame as scheduled"
−default: "No — lay-in or surface-mount frame as scheduled"
−```
−
−## Light Troffer-Integrated Diffusers {toc}
−
−### Light-troffer-integrated diffusers combine a fluorescent or LED troffer light fixture and a linear slot diffuser into a single ceiling unit, used where the architectural design calls for the lighting and HVAC modules to align in the ceiling and where both must be located in the same area. {note}
−
−### The HVAC connection is to a duct collar at the rear of the troffer; the diffuser slots run along the long edges of the troffer. {note}
−
−### The HVAC contractor shall confirm at submittal that the selected troffer fits the electrical fixture supplied for the troffer body, and that the connection sequence allows both trades to complete their work without conflict.
−
−### Troffer-integrated diffusers shall not be used for rooms with high cooling loads, because the troffer's linear slot is generally too small to handle the airflow without excessive NC.
−
−### Light-Troffer-Integrated Diffuser Selection {toc}
−
−```datasheet
−label: Light-Troffer-Integrated Diffuser
−type: radio
−options:
− - "Not used — separate light fixtures and diffusers"
− - "Used — coordinate with lighting fixture model on electrical drawings"
−default: "Not used — separate light fixtures and diffusers"
−```
−
−# Construction, Cores, and Accessories {toc}
−
−## Face and Frame Construction {toc}
−
−### Steel devices shall be fabricated from cold-rolled steel sheet of 22 gauge minimum for the face and 20 gauge minimum for the frame.
−
−### Heavier gauges shall be used where the device dimensions exceed approximately 24 in. on a side or where the device serves a high-static-pressure application.
−
−### Aluminum devices shall be fabricated from extruded or formed aluminum sheet of 0.040 in. minimum for face and frame, with extruded sections used for linear slot diffuser bodies and frames.
−
−### Face Material {toc}
−
−```datasheet
−label: Face Material
−type: radio
−options:
− - "Steel sheet, 22 gauge face / 20 gauge frame"
− - "Steel sheet, heavier gauge per manufacturer for large devices"
− - "Extruded or formed aluminum"
− - "Stainless steel, 22 gauge face / 20 gauge frame"
−default: "Steel sheet, 22 gauge face / 20 gauge frame"
−```
−
−### All visible faces shall be free of burrs, sharp edges, and visible welds.
−
−### Fasteners on visible surfaces shall be flush-finished and color-matched to the device finish.
−
−### Concealed structural fasteners (screws holding the back-pan to the frame, etc.) may be standard plated steel.
−
−## Removable Cores {toc}
−
−### Diffusers with removable cores allow the directional pattern of the device to be changed after installation without removing the entire device from the ceiling, particularly valuable in renovation projects and where the original directional selection proves incorrect during the TAB phase. {note}
−
−### The removable core shall be secured by captive screws or a positive latch mechanism that cannot release accidentally; gravity-only retention is not acceptable.
−
−### Removable Core Selection {toc}
−
−```datasheet
−label: Removable Core Required
−type: radio
−options:
− - "Yes — captive screw or positive latch retention"
− - "No — factory-fixed pattern (lower cost, no field adjustability)"
−default: "Yes — captive screw or positive latch retention"
−```
−
−## Opposed-Blade Dampers (OBDs) {toc}
−
−### An opposed-blade damper (OBD) is an integral damper assembly mounted in the neck of the diffuser or grille, used to throttle airflow at the device for balancing purposes. {note}
−
−### OBDs are an alternative to in-duct volume control dampers and are typically less effective at balancing because they produce more noise per unit of throttling and because they are visible to the occupant. {note}
−
−### OBDs at the device shall not be the primary balancing mechanism for the system.
−
−### The duct system shall include volume control dampers in branch ducts per [[sync/hvac-ductwork]] for primary balancing, with OBDs at devices used only for fine trim of airflow within ±20% of design.
−
−### Specifying OBDs in lieu of volume control dampers is a frequent cost-cutting practice that prevents the TAB contractor from balancing the system and results in noisy devices throttled to choke airflow that should have been balanced upstream. {note}
−
−### OBD Selection {toc}
−
−```datasheet
−label: Integral OBD at Device
−type: radio
−options:
− - "Yes — OBD provided for fine trim only (branch VCD provides primary balancing)"
− - "Yes — OBD as primary balancing mechanism (small systems with simple branches)"
− - "No — balancing entirely by branch VCDs"
−default: "Yes — OBD provided for fine trim only (branch VCD provides primary balancing)"
−```
−
−```datasheet
−label: OBD Operator Access
−type: radio
−options:
− - "Through the device face (visible slot or key access)"
− - "Through the device neck (concealed, key access only)"
− - "Not applicable — no OBD"
−default: "Through the device face (visible slot or key access)"
−```
−
−## Equalizing Grids and Scoops {toc}
−
−### An equalizing grid is a set of adjustable internal blades upstream of the device face that smooths and equalizes the airflow across the neck of the device when connected to a duct with non-uniform velocity profile. {note}
−
−### Equalizing grids shall be specified where the duct geometry upstream of the device does not provide a minimum of three duct diameters of straight duct entering the neck; otherwise the discharge pattern will be skewed and the throw will be asymmetric.
−
−### A scoop (also called a take-off) is a curved or angled diverter inside the main duct at the branch connection that directs a portion of the main airflow into the branch; scoops are not part of the device itself but are commonly bundled with the device order. {note}
−
−### Where high-induction or branch-flow-equalization devices are required for the duct system, the Contractor shall verify that scoops are coordinated between the duct fabrication and the device order.
−
−### Equalizing Grid and Scoop Selection {toc}
−
−```datasheet
−label: Equalizing Grid Provided
−type: radio
−options:
− - "Yes — where boot connection or short duct upstream"
− - "No — straight duct upstream of device neck"
−default: "No — straight duct upstream of device neck"
−```
−
−```datasheet
−label: Scoop or Branch Take-off Provided
−type: radio
−options:
− - "Conical or 45-degree branch take-off in main duct"
− - "Bullhead tee with scoop diverter"
− - "Coordinated with duct fabrication (not part of device order)"
− - "Not applicable"
−default: "Coordinated with duct fabrication (not part of device order)"
−```
−
−## Adjustable Pattern Controllers {toc}
−
−### Adjustable pattern controllers (also called anti-smudge rings, diffuser cones, or drop pattern adjustors) alter the discharge angle of a diffuser between horizontal (cooling mode, attached to ceiling) and downward (heating mode, projecting into the occupied zone). {note}
−
−### Adjustable pattern controllers are valuable in spaces served by a single device for both heating and cooling, particularly with high ceilings or with significant heating-mode supply temperature differentials. {note}
−
−### Adjustable pattern controllers shall be field-set during the TAB process based on the system operating mode that best serves the occupied zone.
−
−### In rooms with prolonged occupancy by stationary occupants (open offices), the cooling-mode horizontal pattern is generally preferred and the controller shall be set accordingly even when heating supply is occasionally used.
−
−### In intermittent-occupancy spaces with infrequent heating use, the controller may be set for downward heating performance, accepting somewhat poorer cooling distribution.
−
−### Adjustable Pattern Controller Selection {toc}
−
−```datasheet
−label: Adjustable Pattern Controller
−type: radio
−options:
− - "Yes — required for combined heating and cooling supply with tall ceilings or high ΔT"
− - "No — single-mode service or moderate conditions where fixed pattern is adequate"
−default: "No — single-mode service or moderate conditions where fixed pattern is adequate"
−```
−
−## Security and Correctional Grilles {toc}
−
−### Security and correctional grilles are heavy-duty grilles installed in correctional facilities, behavioral health units, holding cells, and similar applications where the grille shall resist tampering, ligature attempts, and contraband concealment. {note}
−
−### Security and correctional grille construction shall be heavy steel or stainless steel with tamper-resistant fasteners and shall be selected from a manufacturer's published security or correctional product line.
−
−### Where security grilles also serve as fire dampers, they shall be listed to UL 555 or UL 555S as applicable.
−
−### Security/Correctional-Grade Construction Selection {toc}
−
−```datasheet
−label: Security/Correctional-Grade Construction
−type: radio
−options:
− - "Not required (general commercial/institutional)"
− - "Behavioral health — anti-ligature, smooth face, tamper-resistant"
− - "Correctional — heavy gauge, security fasteners, anti-contraband perforation"
− - "Correctional with integral fire/smoke damper (UL 555/555S listed)"
−default: "Not required (general commercial/institutional)"
−```
−
−### Tamper-resistant fasteners shall be of a type for which the access tool is not commercially available to occupants — typically a manufacturer-specific bit or driver supplied to the facility maintenance staff at substantial completion.
−
−### Where ligature resistance is required, all exposed edges shall be radiused or chamfered and all fasteners shall be flush and recessed below the face surface, presenting a smooth profile that cannot be used to anchor a ligature point.
−
−# Finishes {toc}
−
−## Standard manufacturer finish for steel devices in interior commercial applications shall be electrostatically applied powder-coat in a baked finish.
−
−## Standard color shall be matte white (RAL 9010 or equivalent) selected to match common acoustical ceiling tile.
−
−## Custom colors shall be obtained from the manufacturer's color-match program with submittal of a sample chip from the Architect for approval before production.
−
−## Aluminum devices may be powder-coated or anodized; clear anodized finish provides a natural metallic appearance and is corrosion-resistant, and color anodizing is available in a limited palette of metallic colors. {note}
−
−## Stainless steel devices are typically finished as #4 satin (brushed) or as a powder-coat-painted surface where color is required; mirror-polish finishes show fingerprints and water spots and are not recommended for general interior use. {note}
−
−## Standard Finish Selection {toc}
−
−```datasheet
−label: Standard Finish
−type: select
−options:
− - "Powder-coat matte white (RAL 9010 or equivalent)"
− - "Powder-coat custom color (Architect's selection)"
− - "Clear anodized aluminum"
− - "Color anodized aluminum"
− - "#4 satin stainless steel"
− - "Mill finish (concealed devices only)"
−default: "Powder-coat matte white (RAL 9010 or equivalent)"
−```
−
−### Surface burning characteristics of any non-metal finish material applied to the device (gaskets, sealing strips, foam inserts within the device assembly) shall conform to ASTM E84 with a flame-spread index not greater than 25 and a smoke-developed index not greater than 50 when the device is installed in plenum or ceiling assemblies subject to NFPA 90A.
−
−# Installation {toc}
−
−## Coordination with Ceiling Trades {toc}
−
−### Air distribution devices shall be installed in coordination with the ceiling, lighting, and fire protection trades.
−
−### The Contractor shall participate in coordination drawings (BIM or 2D as established for the project) that show device locations, ceiling grid alignment, light fixture positions, sprinkler heads, and other ceiling-mounted devices.
−
−### Conflicts shall be resolved before any ceiling element is installed; field relocation of devices to avoid lighting fixtures or sprinklers after the ceiling grid is established produces visible misalignment with the grid module and is not acceptable.
−
−### Ceiling Coordination Procedure {toc}
−
−```datasheet
−label: Ceiling Coordination Procedure
−type: radio
−options:
− - "BIM coordination required — device locations finalized at coordination meeting"
− - "2D coordination drawings — device locations finalized before ceiling layout"
− - "Field coordination — devices follow ceiling grid as installed"
−default: "BIM coordination required — device locations finalized at coordination meeting"
−```
−
−## Mounting in Lay-in Ceiling Grids {toc}
−
−### Devices in lay-in ceiling grids shall be supported by hangers attached independently to the structure above, not by the ceiling grid alone.
−
−### The lay-in flange of the device positions the device in the grid module but shall not carry the weight of the device, including the weight of the connected flexible duct.
−
−### Independent support of devices is required by IBC and applicable building codes; ceiling grids are not rated to carry concentrated point loads from suspended HVAC devices. {note}
−
−### A minimum of two safety chains, wires, or rods shall be installed from structure to the device frame at diagonally opposite corners.
−
−### Where the device weight exceeds 20 lb, additional support shall be provided per manufacturer's recommendations.
−
−### Devices shall be plumb and square in the ceiling grid, with the face flush with the surrounding ceiling tile surface within ±1/16 in.
−
−## Mounting in Hard-Lid Ceilings and Walls {toc}
−
−### Devices in hard-lid (gypsum board, plaster, or similar fixed surface) ceilings and walls shall be mounted in framed openings that accommodate the device frame and provide a flush installation.
−
−### Rough openings shall be cut to the manufacturer's published rough opening dimension; oversized or undersized openings shall not be patched with sealant or shims to fit the device.
−
−### The duct collar behind the device shall be sealed to the duct system and to the ceiling penetration to prevent plenum air bypass.
−
−## Duct Connection at Device {toc}
−
−### Devices shall be connected to the duct system by a sheet-metal collar of the same neck dimension as the device.
−
−### The connection between the duct collar and the device neck shall be made with a band clamp, sheet-metal screws, or a flanged interface, and shall be sealed in accordance with the seal class for the duct system per [[sync/hvac-ductwork]].
−
−### Flexible duct connections to devices shall conform to the flexible duct provisions of [[sync/hvac-ductwork]] for support, bend radius, and length.
−
−### Device-to-Duct Connection Method {toc}
−
−```datasheet
−label: Device-to-Duct Connection Method
−type: radio
−options:
− - "Sheet-metal collar with band clamp, sealed per duct seal class"
− - "Direct flange connection to rigid duct, sealed at flange"
− - "Flexible duct to collar, draw-band and tape per [[sync/hvac-ductwork]]"
−default: "Flexible duct to collar, draw-band and tape per [[sync/hvac-ductwork]]"
−```
−
−## Sealing of Plenum and Frame Interface {toc}
−
−### Where supply devices are installed in ceiling plenums used as return air plenums, the device frame shall be sealed to the ceiling surface to prevent supply air from short-circuiting around the frame and into the return plenum.
−
−### Where devices are installed in non-plenum (ducted) ceilings, the frame seal is primarily for visual continuity and acoustic continuity, preventing visible gaps and flanking sound paths around the device. {note}
−
−## Cleanliness and Protection {toc}
−
−### Devices shall be kept in protective packaging until the ceiling system is installed and the room is substantially complete.
−
−### Devices installed before ceiling completion shall be protected from drywall dust, paint overspray, plaster splash, and physical damage.
−
−### Devices contaminated with construction debris on the visible face shall be cleaned with manufacturer-approved methods; abrasive cleaning or cleaning with solvents that damage the powder-coat finish is not acceptable.
−
−### Where damage from construction activity cannot be repaired to match the surrounding devices, the damaged device shall be replaced at the responsible party's expense.
−
−## Removable Core Orientation {toc}
−
−### Diffusers with removable cores and adjustable patterns shall be installed with the pattern set to the design configuration shown on the mechanical drawings, and the pattern setting shall be re-verified during TAB.
−
−### Where the pattern is changed during TAB to improve room air distribution, the as-built device schedule shall record the final pattern setting for each device.
−
−## Adjustable Devices — Field Setting {toc}
−
−### Field-adjustable devices (those with adjustable pattern controllers, integral OBDs, or removable cores) shall be set during the TAB process by the TAB contractor in coordination with the system commissioning agent.
−
−### The OBD position, pattern controller position, and core orientation shall be recorded on the TAB report for each device.
−
−# Testing and Balancing {toc}
−
−## TAB Coordination {toc}
−
−### The TAB contractor shall measure and report supply, return, and exhaust airflow at each device, in accordance with [[sync/testing-adjusting-and-balancing]].
−
−### Balancing shall be performed with the cleaning of the system complete, the design filter media installed, and all devices in their final installed condition.
−
−### The TAB contractor shall set device OBDs and adjustable patterns as part of the balancing procedure and shall record final settings.
−
−### TAB Airflow Tolerance {toc}
−
−```datasheet
−label: TAB Airflow Tolerance at Device
−type: radio
−options:
− - "±10% of design (standard commercial)"
− - "±5% of design (critical applications — laboratory, healthcare, cleanroom)"
−default: "±10% of design (standard commercial)"
−```
−
−## Field NC Verification {toc}
−
−### Field NC verification at devices is generally not required for commercial projects unless the published manufacturer's performance data are unavailable or the design team has reason to believe that field conditions deviate significantly from the published assumptions. {note}
−
−### Where field NC verification is specified, the TAB or acoustic consultant shall measure A-weighted or octave-band sound pressure at the listener position with the system at design airflow, and shall compute NC by the standard tangent method.
−
−### Field NC Verification Selection {toc}
−
−```datasheet
−label: Field NC Verification
−type: radio
−options:
− - "Not required (rely on manufacturer's published NC at design airflow)"
− - "Required — measure at sensitive listener positions in occupied space"
− - "Required — measure at all rooms where NC ≤ 30 specified"
−default: "Not required (rely on manufacturer's published NC at design airflow)"
−```
−
−## Air Pattern Verification {toc}
−
−### For high-aspect-ratio rooms, rooms with non-standard geometries, and rooms with critical comfort requirements (executive offices, conference rooms, healthcare patient rooms), the TAB contractor or commissioning agent shall verify the supply air pattern by smoke test or by hot-wire anemometer traverse.
−
−### Devices with adjustable pattern controllers shall be adjusted to deliver the specified pattern.
−
−### Devices with fixed patterns that fail to deliver the design pattern shall be replaced at no cost to the Owner.
−
−## Smudging Inspection {toc}
−
−### After a minimum of 90 days of continuous operation, the ceiling surface around each ceiling-mounted supply diffuser shall be inspected for smudge patterns.
−
−### Smudging is the deposition of airborne dust on the ceiling surface where the supply jet entrains room air past the diffuser face; the smudge pattern indicates the actual discharge direction and can reveal pattern controllers that have shifted from their set position, devices with damaged face panels, and dust loading that exceeds the design assumptions for the room. {note}
−
−### Heavy smudging that disfigures the ceiling shall be cleaned and the cause investigated; in most cases the cause is excessive room dust loading rather than a device defect.
−
−# Delivery, Storage, and Handling {toc}
−
−## Devices shall be delivered to the site in the manufacturer's original protective packaging, with each device tagged with the project mark or device tag.
−
−## Storage shall be in a clean, dry, and weather-protected area.
−
−## Devices shall not be stacked in a manner that deforms the face panel or damages the frame.
−
−## Removable cores and adjustable internal components shall remain in the device package until immediately before installation to protect the painted finish from scuffs.
−
−## Where devices are delivered before the building is dried-in or before the ceiling system is ready, the Contractor shall maintain the devices in protected storage and shall not install devices in unprotected areas.
−
−## Installation in spaces exposed to construction dust, painting, or wet work shall be deferred until the surrounding work is complete.
−
−# Identification {toc}
−
−## Each device installed shall correspond to the tag indicated on the mechanical drawings and air outlet schedule.
−
−## Where the field-installed device is a substitution from the basis-of-design product, the as-built device schedule shall reflect the substitution.
−
−## Identification of devices in the ceiling for the Owner's facility staff shall be by the air outlet schedule, the as-built mechanical drawings, and the BAS device tagging conventions, not by labels on the visible device face; visible labels on diffusers and grilles are not acceptable for architectural reasons.
−
−# Warranty {toc}
−
−## The Contractor shall warrant the air distribution devices and their installation, including frame fit, face finish, integral dampers, and damper operability, for a period from the date of substantial completion as specified below.
−
−## Warranty shall cover finish defects (peeling, blistering, color shift), structural defects (warping, frame separation), damper failures, and any visible installation deficiency (misalignment, gap with surrounding ceiling, smudging caused by device defect).
−
−## Warranty Period {toc}
−
−```datasheet
−label: Air Distribution Device Warranty Period
−type: select
−options:
− - "1 year from substantial completion"
− - "2 years from substantial completion"
− - "5 years on finish only, 1 year on installation"
−default: "1 year from substantial completion"
−```
−
−### Finish warranty shall cover color-stability and adhesion for the period specified.
−
−### Sun-exposed devices (those receiving direct sunlight through perimeter glazing) shall be subject to manufacturer's UV-resistance specification, and finish failures attributable to UV exposure shall be addressed under the warranty if within the rated UV exposure limits.
−
−# Spare Parts {toc}
−
−## Spare Parts at Substantial Completion {toc}
−
−```datasheet
−label: Spare Parts at Substantial Completion
−type: checkbox
−options:
− - "One spare core of each removable-core diffuser model (where used)"
− - "One spare set of OBD operator keys/tools"
− - "Color-matched touch-up paint for each finish (4 oz minimum per finish)"
− - "Spare tamper-resistant fastener driver bits (for security/correctional applications)"
−default: "Color-matched touch-up paint for each finish (4 oz minimum per finish)"
−```
−
−### Spare cores and parts shall be delivered to the Owner in labeled containers identifying the device model, the project tag of the corresponding installed device, and the date of delivery.
−
−### Where the manufacturer's standard color is selected, color-matched touch-up paint is generally available from the manufacturer in small quantities; for custom colors, the touch-up paint shall be ordered with the original device order to ensure batch match between the installed devices and the touch-up supply.
+---
+title: HVAC Air Distribution Devices
+category: Mechanical / Air Distribution
+description: >
+ When to use: Room-side air distribution devices that terminate a ducted or plenum air system at the boundary of an occupied space - supply outlets (square and rectangular face, round face, linear slot, swirl, displacement, light-fixture-integrated), return and exhaust inlets, and transfer openings, together with the frames, cores, integral dampers, and finishes furnished as part of the device. Covers the performance criteria that govern occupant comfort and acoustic acceptability (throw at 50, 100, and 150 fpm terminal velocities, ADPI, occupied-zone air speed, occupied-space sound level), device materials for dry, wet, and corrosive service, exposed finishes, security and anti-ligature construction, installation and support, and field balancing and verification. Applies to new construction and to renovation where devices are connected to a distribution system.
+ Not intended for: Air terminal units and fan-powered boxes upstream of the device; duct construction, sealing, and leakage testing; air-handling unit casings, coils, and filter sections; system-wide testing, adjusting, and balancing procedure and report format; exterior intake and relief louvers set in the building envelope; kitchen exhaust hoods and grease-laden exhaust terminations; standalone fire, smoke, and combination fire/smoke damper assemblies; unidirectional-flow outlets and terminal HEPA housings serving cleanrooms and critical containment spaces; radiant ceiling panels and chilled beams.
+---
+
+# Scope {toc}
+
+## This standard covers the selection basis, performance criteria, materials, construction, finish, installation, and field verification of room-side air distribution devices - the outlets and inlets at which a ducted or plenum air system meets an occupied space. {note}
+
+## Devices covered are supply outlets of every common face configuration, return and exhaust inlets, and transfer openings between spaces, together with the frames, cores, integral dampers, equalizing grids, and finishes furnished as part of the device assembly. {note}
+
+## The following are outside the scope of this standard: {note}
+
+- Air terminal units, fan-powered boxes, and their controls upstream of the device, covered by [[sync/air-terminal-units]]
+- Duct construction, sealing, hangers, and leakage testing, covered by [[sync/hvac-ductwork]]
+- Air-handling unit casings, coils, and filter sections, covered by [[sync/air-handling-units]]
+- System-wide testing, adjusting, and balancing procedure and report format, covered by [[sync/testing-adjusting-and-balancing]]
+- Exterior intake and relief louvers set in the building envelope
+- Kitchen exhaust hoods and grease-laden exhaust terminations
+- Fire dampers, smoke dampers, and combination fire and smoke dampers furnished as standalone assemblies rather than integral to a device
+- Unidirectional-flow outlets and terminal HEPA filter housings serving cleanrooms and critical containment spaces
+- Radiant ceiling panels and chilled beams, whose primary thermal exchange is not by air delivery
+
+## Aerodynamic and sound performance cited for any device under this standard shall be derived from testing in accordance with ANSI/ASHRAE 70.
+
+## Occupied-space sound levels attributed to air distribution devices shall be estimated in accordance with ANSI/AHRI 885.
+
+## Air diffusion performance in the occupied zone shall be evaluated by the Air Diffusion Performance Index method of the ASHRAE Handbook - Fundamentals, Space Air Diffusion chapter.
+
+# Referenced Standards {toc}
+
+## Equipment, materials, and installation 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 |
+|----------|-------|
+| ANSI/ASHRAE 70 | Method of Testing the Performance of Air Outlets and Air Inlets |
+| ANSI/ASHRAE 113 | Method of Testing for Room Air Diffusion |
+| ANSI/ASHRAE 55 | Thermal Environmental Conditions for Human Occupancy |
+| ANSI/ASHRAE 62.1 | Ventilation and Acceptable Indoor Air Quality |
+| ASHRAE Handbook - Fundamentals | Space Air Diffusion chapter (ADPI, throw, terminal velocity, characteristic room length) |
+| ANSI/AHRI 885 | Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminals and Air Outlets |
+| ANSI/ASA S12.2 | Criteria for Evaluating Room Noise |
+| NFPA 90A | Standard for the Installation of Air-Conditioning and Ventilating Systems |
+| ASTM E84 | Standard Test Method for Surface Burning Characteristics of Building Materials |
+| ASTM A653 | Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process |
+| ASTM A1008 | Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength Low-Alloy and High-Strength Low-Alloy with Improved Formability |
+| ASTM A240 | Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications |
+| ASTM B209 | Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate |
+| ASTM B221 | Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes |
+| ASTM B244 | Standard Test Method for Measurement of Thickness of Anodic Coatings on Aluminum by Eddy-Current Method |
+| ASTM D3359 | Standard Test Methods for Rating Adhesion by Tape Test |
+| UL 555 | Fire Dampers |
+| UL 555S | Smoke Dampers |
+| ICC A117.1 | Accessible and Usable Buildings and Facilities |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for the Engineer of Record's review and return before any device covered by the submittal is procured:
+
+- Manufacturer product data for each device type, covering face configuration, face and neck dimensions, frame style, base material, finish, core type, and integral accessories
+- Rated performance data for each scheduled device at its scheduled airflow, reporting throw to the 50, 100, and 150 fpm terminal velocities, total pressure at the neck, and radiated sound power, each identified as derived from ANSI/ASHRAE 70 testing
+- Occupied-space sound level estimate for each scheduled device prepared per ANSI/AHRI 885, stating the room correction values used
+- Air Diffusion Performance Index calculation for each typical space type, showing the outlet selected, its position, its scheduled airflow, the characteristic room length used, and the resulting index
+- Finish sample in the specified color for each combination of base material and finish supplied
+- Frame cross-section detail for every ceiling and wall construction into which devices are installed, showing the interface with the finished surface
+- Device schedule keyed to the mechanical drawings, listing tag, device type, face size, neck size, scheduled airflow, frame style, finish, and integral damper
+- Independent support detail for each device whose installed weight exceeds 20 lb
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Product data for each device type"
+ - "Rated performance data at scheduled airflow"
+ - "Occupied-space sound level estimate per AHRI 885"
+ - "ADPI calculation for each typical space type"
+ - "Finish sample for each material and finish combination"
+ - "Frame cross-section detail for each ceiling and wall type"
+ - "Device schedule keyed to the mechanical drawings"
+ - "Independent support detail for devices over 20 lb"
+default:
+ - "Product data for each device type"
+ - "Rated performance data at scheduled airflow"
+ - "Occupied-space sound level estimate per AHRI 885"
+ - "ADPI calculation for each typical space type"
+ - "Finish sample for each material and finish combination"
+ - "Frame cross-section detail for each ceiling and wall type"
+ - "Device schedule keyed to the mechanical drawings"
+```
+
+### No device shall be released for fabrication or procurement until the submittal covering it has been reviewed and returned.
+
+### Where the Contractor proposes a device from a manufacturer other than the one on which the design was based, the submittal shall include a side-by-side comparison of throw, total pressure, and sound power at the scheduled airflow for the proposed and the scheduled device.
+
+## Closeout Submittals {toc}
+
+### Before final acceptance of the air distribution system, the Contractor shall submit the following:
+
+- As-built device schedule recording every field substitution together with the review documentation for it
+- Operation and maintenance instructions for removable cores, pattern controllers, and integral dampers, including the procedure for restoring a setting disturbed during maintenance
+- Record of the final integral damper position, pattern controller position, and core orientation at each device
+- Balancing report extract listing the measured airflow at each device, coordinated with [[sync/testing-adjusting-and-balancing]]
+- Manufacturer warranty documentation covering material and finish
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "As-built device schedule recording field substitutions"
+ - "Operation and maintenance instructions for cores, controllers, and dampers"
+ - "Record of final damper, controller, and core settings at each device"
+ - "Balancing report extract listing measured airflow at each device"
+ - "Manufacturer warranty documentation for material and finish"
+default:
+ - "As-built device schedule recording field substitutions"
+ - "Operation and maintenance instructions for cores, controllers, and dampers"
+ - "Record of final damper, controller, and core settings at each device"
+ - "Balancing report extract listing measured airflow at each device"
+ - "Manufacturer warranty documentation for material and finish"
+```
+
+# Quality Assurance {toc}
+
+## Manufacturer Qualifications {toc}
+
+### Devices shall be produced by a manufacturer that has continuously produced air outlets and inlets for commercial service for not less than five years.
+
+### The manufacturer shall publish a catalog covering the full range of devices supplied to the project, including rated performance at each cataloged neck size.
+
+### The manufacturer shall maintain replacement cores, pattern controllers, and integral damper assemblies for the devices supplied for not less than ten years after the date of Substantial Completion.
+
+## Basis of Published Performance Data {toc}
+
+### Published aerodynamic performance shall be derived from testing in accordance with ANSI/ASHRAE 70, and the data sheet shall identify that standard as the basis.
+
+### Published sound power shall be derived from testing in accordance with ANSI/ASHRAE 70, and any occupied-space sound level shown shall identify the ANSI/AHRI 885 room correction values used to produce it.
+
+### A device whose published performance is not traceable to ANSI/ASHRAE 70 testing shall not be substituted for a scheduled device.
+
+### Sound power and occupied-space sound pressure are different quantities: sound power is a property of the device measured in a laboratory, while the level a listener experiences depends on room absorption, the number of devices, and the distance from the device to the listener. ANSI/AHRI 885 is the method that converts the first into an estimate of the second. {note}
+
+## Appearance Consistency Within a Visible Ceiling Area {toc}
+
+### Within any continuous ceiling area visible from a single vantage point, all devices of the same category shall be supplied by one manufacturer.
+
+### Face pattern, border profile, corner detail, and color tint vary between manufacturers by amounts that are invisible on a submittal sheet and obvious in an installed ceiling, which is why the single-source requirement is written per visible area rather than per project. {note}
+
+## Installed Device Mock-Up {toc}
+
+### The mock-up requirement for the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Installed Device Mock-Up
+type: radio
+options:
+ - "Not required"
+ - "One device of each type installed in the actual ceiling assembly with the specified finish"
+ - "One device of each type plus one complete ceiling bay including lighting and sprinkler devices"
+default: "Not required"
+```
+
+### Where a mock-up is required, the Contractor shall install it before releasing the balance of the device order, and the Architect and the Engineer of Record shall review it for finish match, frame fit, and alignment with the ceiling module.
+
+### Where the parties disagree whether an installed mock-up meets the finish match and frame fit requirements, the Architect shall make the initial determination.
+
+# Room Air Distribution Strategy {toc}
+
+## The strategy by which conditioned air is introduced into and removed from the occupied space determines which device families are usable, and it shall be as indicated in the datasheet.
+
+```datasheet
+label: Room Air Distribution Strategy
+type: select
+options:
+ - "Overhead mixing"
+ - "Displacement ventilation"
+ - "Underfloor air distribution"
+ - "Stratified ventilation in high-bay spaces"
+default: "Overhead mixing"
+```
+
+## In an overhead mixing system the supply jet is deliberately made energetic enough to entrain and mix the whole room volume, so comfort is governed by throw and by the residual velocity that reaches the occupied zone. {note}
+
+## In a displacement or underfloor system the supply air is introduced at low velocity near the floor and rises by buoyancy as it collects heat from occupants and equipment, so comfort is governed by the temperature and velocity of the air at ankle level and by the vertical temperature gradient. {note}
+
+## Where ceilings are tall, cooling loads are moderate, and the floor-to-return path is unobstructed by full-height partitions, a displacement outlet delivers ventilation air to the breathing zone before it has mixed with room air, and it does so at a lower supply-to-room temperature difference than an overhead system requires. {note}
+
+## Where displacement ventilation is selected and the space sensible cooling load exceeds 30 Btu/h/ft² of floor area, the Engineer of Record shall document the supply air temperature and the resulting floor-level air temperature and speed at the design load.
+
+## Where displacement or underfloor distribution is selected, return and relief openings shall be located at or near the ceiling so the buoyant plume is not short-circuited back into the supply path.
+
+# Throw, Terminal Velocity, and Occupied-Zone Air Motion {toc}
+
+## Throw is the distance from a supply outlet to the point at which the jet has decayed to a stated terminal velocity, and it is the single characteristic that most directly determines whether a room mixes or stagnates. {note}
+
+## Three terminal velocities are published for most supply outlets, and each answers a different question: the 150 fpm distance indicates how far the jet stays attached to the ceiling and washes a perimeter surface, the 100 fpm distance indicates the practical reach of the jet across the room, and the 50 fpm distance indicates how far residual motion carries before it falls into the occupied zone. {note}
+
+## The terminal velocity at which throw is scheduled and verified shall be as indicated in the datasheet.
+
+```datasheet
+label: Terminal Velocity Basis for Scheduled Throw
+type: range
+unit: fpm
+min: 50
+max: 150
+setpoints: [50, 100, 150]
+default: 100
+```
+
+## For overhead mixing systems, the scheduled throw of each supply outlet shall place the jet boundary at the stated terminal velocity within one outlet spacing of the perimeter wall or of the boundary of the opposing outlet, measured at the ceiling plane.
+
+## Air speed within the occupied zone attributable to the supply outlets shall not exceed the limit indicated in the datasheet at the scheduled airflow, evaluated against the draft criteria of ANSI/ASHRAE 55.
+
+```datasheet
+label: Maximum Occupied-Zone Air Speed from Supply Outlets
+type: range
+unit: fpm
+min: 20
+max: 80
+setpoints: [20, 30, 40, 50, 60, 70, 80]
+default: 50
+```
+
+## Where the occupied zone is evaluated by field measurement rather than by calculation, air speed and air temperature shall be measured in accordance with ANSI/ASHRAE 113.
+
+## Selecting a supply outlet by neck size and airflow alone, without checking throw and sound at that airflow, is the most common origin of the draft and noise complaints that surface after occupancy. {note}
+
+# Air Diffusion Performance Index {toc}
+
+## The Air Diffusion Performance Index is the percentage of measurement points in the occupied zone at which the effective draft temperature - a combined measure of local air temperature deviation and local air speed - falls inside the comfort band. It reduces the interaction of throw, room geometry, and load to a single number that can be compared across outlet selections. {note}
+
+## Air diffusion performance shall be calculated for each typical space type in cooling mode, and the outlet type, quantity, position, and scheduled airflow shall be adjusted until the index meets the target indicated in the datasheet.
+
+```datasheet
+label: Air Diffusion Performance Index Target for Cooling Mode
+type: range
+unit: '%'
+min: 70
+max: 95
+setpoints: [70, 75, 80, 85, 90, 95]
+default: 80
+```
+
+## An index of 80 is the value ASHRAE research identified as satisfying most occupants of a space with uniform activity and clothing levels, which is why it serves as the reference point rather than as a ceiling. {note}
+
+## Where the space sensible cooling load exceeds 30 Btu/h/ft² of floor area, the ratio of throw to characteristic room length shall be selected from the ASHRAE Handbook - Fundamentals tables for the outlet type rather than by proportioning from a lower-load selection.
+
+## Where the target index exceeds 90, meeting it generally calls for more outlets than the scheduled airflow alone requires, or for pattern adjustment at each outlet, because the index becomes sensitive to small departures from the ideal throw ratio. {note}
+
+## The index is defined for cooling-mode operation and does not describe heating-mode distribution, which is governed instead by whether the warm jet penetrates to the occupied zone. {note}
+
+# Heating-Mode Supply Air Distribution {toc}
+
+## Supply air warmer than the room is buoyant, so it resists the downward component of a ceiling outlet's discharge and tends to remain as a stratified layer against the ceiling while the occupied zone stays cold. {note}
+
+## Where a ceiling supply outlet serves both heating and cooling, the Engineer of Record shall verify that the heating-mode jet reaches the occupied zone at the design heating supply temperature.
+
+## Where a ceiling supply outlet serves both heating and cooling in a space with a ceiling height above 12 ft, the outlet shall be furnished with a field-adjustable pattern controller, or heating-mode distribution shall be documented by a separate calculation.
+
+## Where the space is heated by a source other than the ceiling supply outlets, such as perimeter radiation or radiant panels, the outlets need only satisfy the cooling-mode criteria of this standard.
+
+# Device-Generated Sound {toc}
+
+## The occupied-space sound level attributable to each device at its scheduled airflow shall not exceed the limit indicated in the datasheet.
+
+```datasheet
+label: Maximum Device-Generated Sound Level in the Occupied Space (NC)
+type: range
+min: 15
+max: 55
+setpoints: [15, 20, 25, 30, 35, 40, 45, 50, 55]
+```
+
+## Where a lower sound limit is indicated for a specific space, that limit shall govern in that space.
+
+## Sound criteria vary by how the space is used, and the ranges commonly applied are: {note}
+
+- NC 25 to NC 30 for performance spaces, recording and broadcast rooms, and executive offices
+- NC 30 to NC 35 for private offices, classrooms, conference rooms, and patient rooms
+- NC 35 to NC 40 for open offices, libraries, retail sales areas, and restaurants
+- NC 40 to NC 45 for corridors, lobbies, and light industrial spaces
+- NC 45 to NC 50 for kitchens, gymnasiums, and mechanical and service areas
+
+## The method used to convert published device sound power into an occupied-space level shall be as indicated in the datasheet.
+
+```datasheet
+label: Occupied-Space Sound Level Estimating Method
+type: radio
+options:
+ - "Published device sound level using the AHRI 885 default room correction"
+ - "Project-specific AHRI 885 calculation by the Engineer of Record"
+default: "Published device sound level using the AHRI 885 default room correction"
+```
+
+## The default room correction embedded in published selection tables assumes a room of ordinary absorption with the listener a stated distance from the device, so it understates the level reached in a hard-surfaced, reverberant space such as an atrium, a lobby, or a natatorium. {note}
+
+## Where the project-specific estimating method is selected, the calculation shall use the room absorption, device quantity, and listener distance of the actual space, and shall be included in the action submittal.
+
+## Where an integral damper is throttled, it generates sound that the device's own rating does not include, so the sound estimate shall be made at the throttled position expected at final balance rather than at the wide-open position.
+
+## Sound criteria expressed as NC values shall be evaluated by the tangent method of ANSI/ASA S12.2 where field measurement is performed.
+
+# Airflow Resistance at the Device {toc}
+
+## The total pressure required to deliver the scheduled airflow through the device is the device's contribution to the system resistance the fan must overcome, and it shall not exceed the limit indicated in the datasheet at the scheduled airflow.
+
+```datasheet
+label: Maximum Device Total Pressure at Scheduled Airflow
+type: range
+unit: 'in. w.g.'
+min: 0.02
+max: 0.50
+setpoints: [0.02, 0.05, 0.075, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50]
+```
+
+## Device pressure, sound, and throw move together: forcing a given airflow through a smaller neck raises all three at once, so a limit set tight enough to protect fan energy also constrains how far the selection can be pushed for throw. {note}
+
+## The total pressure of each device at its scheduled airflow shall be included in the fan external static pressure calculation for the system it serves.
+
+## Where an integral damper is provided, the pressure used in the fan calculation shall be the pressure at the throttled position expected at final balance.
+
+# Supply Outlet Types {toc}
+
+## Square and Rectangular Face Outlets {toc}
+
+### A square or rectangular face outlet discharges a horizontal jet in one, two, three, or four directions across the ceiling, where it attaches to the ceiling surface and decays along the throw distance. {note}
+
+### The discharge pattern is fixed by the core installed in the outlet, and one-way, two-way, and three-way patterns are used where an adjacent wall or a neighboring outlet would otherwise be washed by the jet. {note}
+
+### The discharge pattern of each square and rectangular face outlet shall be selected so that no jet is directed at a wall closer than the throw to the scheduled terminal velocity, and so that opposing jets from adjacent outlets do not collide within the occupied zone.
+
+### Where a square or rectangular face outlet serves a space in heating mode with no other heat source, it shall be furnished with a pattern controller capable of a downward discharge.
+
+## Round Face Outlets {toc}
+
+### A round face outlet discharges radially through a full circle and produces a uniform horizontal throw in every direction, which suits an open area with no near wall on any side. {note}
+
+### A round face outlet shall not be located closer to a wall than its throw to the scheduled terminal velocity unless it is furnished with a sectored core that blanks the discharge toward the wall.
+
+## Linear Slot Outlets {toc}
+
+### A linear slot outlet discharges through one or more narrow continuous slots and produces a long, thin jet, which suits washing a glazed perimeter, articulating the edge of a soffit, and running in line with linear light fixtures in an exposed ceiling. {note}
+
+### The number of slots changes the trade between reach and sound at a fixed airflow: adding slots at the same total airflow lowers the discharge velocity through each, which reduces generated sound and shortens throw, while removing slots does the reverse. {note}
+
+### Inactive lengths within a continuous linear slot run shall be blanked off internally by the manufacturer so that the exposed slot appears continuous while air is discharged only along the active length.
+
+### Sections joined to form a continuous linear slot run shall be aligned with concealed splines or alignment pins so that no offset between adjacent sections is visible along the run.
+
+### End conditions at the extremities of a continuous linear slot run shall be coordinated with the Architect before fabrication.
+
+### Where a linear slot outlet serves a space in both heating and cooling modes, it shall be furnished with a pattern controller that biases the jet horizontally in cooling and downward in heating.
+
+## Swirl Outlets {toc}
+
+### A swirl outlet imparts rotation to the discharge, which induces room air into the jet at a high rate and collapses the temperature difference within a short distance of the outlet. {note}
+
+### Where ceilings are high enough that a horizontal-discharge outlet would over-throw the space, or where the supply-to-room temperature difference is large, the rapid induction of a swirl outlet brings the jet close to room temperature before it descends into the occupied zone. {note}
+
+### Where swirl outlets are used with a variable-air-volume system, the selection shall be verified at the minimum scheduled airflow as well as at the maximum, because the induction that makes the outlet work falls off with discharge velocity.
+
+## Displacement Outlets {toc}
+
+### A displacement outlet has a large free area and discharges at a face velocity low enough that the supply air spreads across the floor as a shallow layer rather than as a jet. {note}
+
+### Displacement outlets shall be located so that no seated occupant is within the near-floor spreading zone published by the manufacturer for the scheduled airflow.
+
+### Displacement outlets shall be protected from impact where they are floor-mounted in circulation paths, by a bollard, a recess, or a reinforced face section.
+
+### Furniture, full-height partitions, and stored material placed against a displacement outlet defeat the floor-level spreading the outlet depends on, so the clear zone in front of the outlet is a coordination item with the furniture layout rather than a property of the device. {note}
+
+## Light-Fixture-Integrated Outlets {toc}
+
+### A light-fixture-integrated outlet combines a luminaire body and a slot outlet in one ceiling unit, discharging along the long edges of the fixture from a duct collar at its back. {note}
+
+### The Contractor shall confirm at submittal that the integrated outlet is compatible with the luminaire supplied under the electrical scope, including the lamp or driver compartment, the ceiling module, and the sequence in which each trade installs its portion.
+
+### The scheduled airflow at a light-fixture-integrated outlet shall be verified against the outlet's rated sound at that airflow, because the slot free area available within a luminaire body is smaller than that of a comparable standalone slot outlet.
+
+# Return and Exhaust Inlets {toc}
+
+## An inlet draws air from a region close to its face rather than from across the room, so its location has far less effect on room air motion than a supply outlet's does. Its consequential failure mode is short-circuiting - drawing supply air back before it has served the occupied zone. {note}
+
+## Return and exhaust inlets shall be located so that supply air is not drawn directly from a supply outlet into an inlet without passing through the occupied zone.
+
+## The core style of return and exhaust inlets shall be as indicated in the datasheet.
+
+```datasheet
+label: Return and Exhaust Inlet Core Style
+type: radio
+options:
+ - "Eggcrate core, 1/2 in. × 1/2 in. cell"
+ - "Eggcrate core, 1/2 in. × 1 in. cell"
+ - "Fixed horizontal blade louver"
+ - "Fixed 45° deflection blade louver"
+ - "Perforated face with concealed back-pan"
+ - "Perforated face matching the supply outlet face pattern"
+default: "Eggcrate core, 1/2 in. × 1/2 in. cell"
+```
+
+## The net face velocity through a return or exhaust inlet at its scheduled airflow shall not exceed the limit indicated in the datasheet.
+
+```datasheet
+label: Maximum Net Face Velocity at Return and Exhaust Inlets
+type: range
+unit: fpm
+min: 200
+max: 800
+setpoints: [200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800]
+default: 500
+```
+
+## Net face velocity is computed on free area rather than on nominal face area, and the two differ by a factor that depends on the core style, so an inlet sized on nominal area alone runs faster and louder than intended. {note}
+
+## Where an inlet is within the acoustically sensitive area of a space with a sound limit of NC 30 or lower, the face velocity shall be selected at the lower end of the permitted range so that the inlet does not become the governing sound source.
+
+## Where an exhaust duct conveys moisture, fumes, or condensate that would corrode a dissimilar metal at the connection, the inlet shall be of the same material as the duct it serves.
+
+# Transfer Openings Between Spaces {toc}
+
+## A transfer opening moves air between two adjacent spaces without dedicated ductwork, most often relieving supply air from a private space into a corridor or plenum that serves as the return path. {note}
+
+## An untreated transfer opening carries speech as readily as it carries air, so a direct louver between a private space and a corridor removes the acoustic separation the partition was built to provide. An acoustically treated transfer assembly interposes a lined, baffled plenum between the two faces, which absorbs speech-frequency sound while leaving a low-resistance airflow path. {note}
+
+## Transfer openings between a space with a speech-privacy requirement and an adjoining space shall be acoustically treated assemblies.
+
+## A transfer opening shall not penetrate a fire-rated or smoke-rated assembly unless a damper listed to UL 555 or UL 555S, as applicable to the rating, is installed in the penetration.
+
+## The Contractor shall confirm the rating of every assembly through which a transfer opening passes before cutting the opening.
+
+## Transfer openings shall not be installed in an assembly enclosing an exit stair, an exit passageway, or an elevator hoistway.
+
+# Device Materials for Service Environments {toc}
+
+## Devices in Dry Interior Spaces {toc}
+
+### The base material of devices serving dry interior spaces shall be as indicated in the datasheet.
+
+```datasheet
+label: Device Material for Dry Interior Spaces
+type: select
+options:
+ - "Steel sheet"
+ - "Extruded or formed aluminum"
+ - "Type 304 stainless steel"
+ - "Type 316 stainless steel"
+default: manufacturer
+```
+
+### Steel, aluminum, and stainless steel all perform indefinitely in a dry conditioned interior, and manufacturers build different device families in different base metals, which is why the material for ordinary interior service can be left to the manufacturer's standard offering for the device type selected. {note}
+
+### Where the datasheet leaves the material for dry interior spaces to the manufacturer, the manufacturer shall state the base metal supplied for each device type in the action submittal.
+
+### Steel devices shall be zinc-coated to ASTM A653 or cold-rolled to ASTM A1008 with a corrosion-inhibiting primer applied before the finish coat.
+
+### Aluminum devices shall be sheet to ASTM B209 or extruded profile to ASTM B221.
+
+### Stainless steel devices shall be sheet to ASTM A240 in the type indicated in the datasheet.
+
+## Devices in Wet and High-Humidity Spaces {toc}
+
+### The base material of devices serving showers, locker rooms, natatoriums, commercial kitchens, laundries, and comparable spaces shall be as indicated in the datasheet.
+
+```datasheet
+label: Device Material for Wet and High-Humidity Spaces
+type: select
+options:
+ - "Extruded or formed aluminum"
+ - "Type 304 stainless steel"
+ - "Type 316 stainless steel"
+ - "Powder-coated steel sheet with sealed edges"
+```
+
+### A painted steel device in a sustained-moisture environment corrodes first at sheared edges and at fastener penetrations, where the coating is thinnest or broken, and the visible face can stay presentable for several years while the frame behind it is already failing. {note}
+
+### Where a natatorium or any space treated with chlorine-based or bromine-based water chemistry is served, devices shall be Type 316 stainless steel and all exposed fasteners shall be of the same alloy.
+
+## Devices in Corrosive Exhaust Service {toc}
+
+### The base material of devices serving laboratory exhaust, chemical storage, battery rooms, and comparable corrosive environments shall be as indicated in the datasheet.
+
+```datasheet
+label: Device Material for Corrosive Exhaust Service
+type: select
+options:
+ - "Type 316 stainless steel"
+ - "Type 304 stainless steel"
+ - "Extruded or formed aluminum"
+ - "Epoxy-coated steel sheet"
+ - "Molded fiberglass-reinforced polyester"
+ - "Polypropylene or PVC"
+```
+
+### Aluminum resists many corrosive atmospheres but is attacked by both strongly alkaline and chloride-bearing solutions, so it holds up in an environment whose specific chemistry has been checked against it and not as a general substitute for stainless steel. {note}
+
+### Devices of fiberglass-reinforced polyester, polypropylene, or PVC installed in a plenum or in a ceiling assembly regulated by NFPA 90A shall have a flame spread index not greater than 25 and a smoke developed index not greater than 50 when tested to ASTM E84.
+
+### The Engineer of Record shall confirm the exhaust stream chemistry against the manufacturer's chemical resistance data before the material selection is released for fabrication.
+
+## Sheet Thickness and Fabrication {toc}
+
+### Steel device faces shall be not lighter than 22 gauge and steel device frames not lighter than 20 gauge.
+
+### Aluminum device faces and frames shall be not less than 0.040 in. thick, and linear slot bodies and continuous frames shall be extruded profiles.
+
+### Stainless steel device faces shall be not lighter than 22 gauge and stainless steel frames not lighter than 20 gauge.
+
+### Where any face dimension of a device exceeds 24 in., the face and frame thickness shall be increased as required to hold the face flat within 1/16 in. across its span under the scheduled airflow.
+
+### Exposed surfaces shall be free of burrs, sharp edges, weld spatter, and visible weld seams.
+
+### Fasteners on exposed surfaces shall be flush with the face and finished to match it.
+
+### Concealed fasteners securing back-pans, collars, and internal components may be plated carbon steel except where the device material is stainless steel, in which case they shall be of the same alloy as the device.
+
+# Exposed Finishes {toc}
+
+## The exposed finish of devices shall be as indicated in the datasheet.
+
+```datasheet
+label: Exposed Finish
+type: select
+options:
+ - "Powder-coat white"
+ - "Powder-coat off-white"
+ - "Powder-coat black"
+ - "Powder-coat custom color to the Architect's selection"
+ - "Clear anodized"
+ - "Color anodized"
+ - "No. 4 satin stainless steel"
+ - "Mill finish"
+default: "Powder-coat white"
+```
+
+## A white or off-white powder coat is used on most ceiling devices because it disappears against the acoustical tile it sits in, and manufacturers hold their standard white close to the common tile whites for that reason. {note}
+
+## A mill finish leaves the base metal uncoated, so it carries no color match to the surrounding surface and shows fabrication marks and handling scuffs; it is used where the device face is not architecturally exposed. {note}
+
+## Powder coating shall be electrostatically applied and oven-cured over a cleaned and pretreated substrate.
+
+## Powder coat adhesion shall meet a classification of not less than 4B when tested to ASTM D3359.
+
+## Anodized finishes shall be applied only to aluminum devices, and the anodic coating thickness shall be not less than 0.7 mil verified to ASTM B244.
+
+## A No. 4 satin finish shall be applied only to stainless steel devices, and the graining direction shall be consistent across every device in a continuous visible area.
+
+## Where a custom color is selected, the manufacturer's color-match program shall be used and a production sample shall be submitted for the Architect's approval before the order is released.
+
+## Where devices in one visible area are supplied in more than one base material with the same specified color, the Contractor shall submit a sample of each material finished in that color, since the same coating over steel, aluminum, and stainless steel does not necessarily read as the same color.
+
+## Gaskets, sealing strips, and foam inserts within a device installed in a plenum or in a ceiling assembly regulated by NFPA 90A shall have a flame spread index not greater than 25 and a smoke developed index not greater than 50 when tested to ASTM E84.
+
+## The exposed border fastening method shall be as indicated in the datasheet.
+
+```datasheet
+label: Exposed Border Fastening
+type: radio
+options:
+ - "Exposed countersunk fasteners finished to match the face"
+ - "Concealed fasteners with a spring-latch or hinged face"
+default: "Exposed countersunk fasteners finished to match the face"
+```
+
+# Cores, Dampers, and Integral Accessories {toc}
+
+## Discharge Pattern Adjustment {toc}
+
+### The means by which the discharge pattern of supply outlets may be changed after installation shall be as indicated in the datasheet.
+
+```datasheet
+label: Discharge Pattern Adjustment at Supply Outlets
+type: select
+options:
+ - "Factory-fixed pattern determined by the outlet model"
+ - "Interchangeable removable core"
+ - "Field-adjustable pattern controller"
+ - "Interchangeable removable core with a field-adjustable pattern controller"
+```
+
+### A removable core lets the discharge direction be changed from below the ceiling without disturbing the device, the duct connection, or the ceiling tile, which matters most during balancing and in tenant fit-outs where the room layout changes after the ceiling is built. {note}
+
+### A removable core shall be retained by captive fasteners or a positive latch, and shall not rely on gravity or friction alone to stay seated.
+
+### A field-adjustable pattern controller shall hold its set position against the discharge velocity at the scheduled airflow without additional fastening.
+
+### The position of every adjustable core and pattern controller shall be set during balancing and recorded on the closeout record of settings.
+
+## Integral Volume Dampers {toc}
+
+### The integral volume damper provided at devices shall be as indicated in the datasheet.
+
+```datasheet
+label: Integral Volume Damper at the Device
+type: radio
+options:
+ - "Opposed-blade damper at each supply device"
+ - "Opposed-blade damper at each supply device and each return device"
+ - "Butterfly damper at each round-neck supply device"
+ - "No integral damper at the device"
+default: "Opposed-blade damper at each supply device"
+```
+
+### An integral damper throttles at the point where the air is about to enter the room, so the sound it generates is not attenuated by any duct run before it reaches the listener. A duct-mounted damper placed several diameters upstream generates comparable sound but delivers far less of it to the occupied space. {note}
+
+### Primary balancing of each branch shall be performed at duct-mounted volume dampers provided under [[sync/hvac-ductwork]].
+
+### Integral dampers at devices shall be used for final trim within 20% of the scheduled airflow and shall not be used to absorb a branch imbalance.
+
+### Unless the datasheet selects a device without an integral damper, an integral damper shall not be installed as the only means of adjusting airflow on a branch serving more than one device.
+
+### The access provided to the integral damper operator shall be as indicated in the datasheet.
+
+```datasheet
+label: Integral Damper Operator Access
+type: radio
+options:
+ - "Adjustable through the device face"
+ - "Adjustable through the device neck with a key"
+ - "Not applicable where no integral damper is provided"
+default: "Adjustable through the device face"
+```
+
+## Equalizing Grids and Duct Take-Offs {toc}
+
+### An equalizing grid is a set of adjustable blades set in the device neck that redistributes an uneven approach velocity across the neck before the air reaches the face. {note}
+
+### An equalizing grid shall be provided at each supply device whose neck is served by less than three neck diameters of straight duct.
+
+### Without an equalizing grid, a device fed through a boot, a hard elbow, or a sharply bent flexible duct discharges more air on one side of the face than the other, which skews the pattern and shortens the throw on the starved side. {note}
+
+### Branch take-offs at the main duct shall be furnished and installed under [[sync/hvac-ductwork]], and the Contractor shall confirm before fabrication that no take-off fitting has been assumed to arrive with the device order.
+
+## Insulated Back-Pans and Condensation Control {toc}
+
+### The back-pan insulation provided at supply devices shall be as indicated in the datasheet.
+
+```datasheet
+label: Back-Pan Insulation at Supply Devices
+type: radio
+options:
+ - "Not required"
+ - "Factory-applied back-pan insulation at supply devices"
+ - "Field-applied back-pan insulation at supply devices"
+default: "Not required"
+```
+
+### A supply device carrying cold air through a humid ceiling plenum can drop the back-pan below the plenum dew point, and the resulting condensation runs down the neck and stains the ceiling tile from above before anything is visible on the face. {note}
+
+### Where the ceiling plenum is unconditioned, is open to outdoor air, or is in a space whose plenum dew point exceeds the design supply air temperature, supply device back-pans shall be insulated.
+
+### Insulation applied to a device back-pan shall be sealed at all edges and penetrations so that no insulation face is exposed to the airstream.
+
+## Security and Anti-Ligature Construction {toc}
+
+### Security and anti-ligature construction at devices shall be as indicated in the datasheet.
+
+```datasheet
+label: Security and Anti-Ligature Construction
+type: radio
+options:
+ - "Not required"
+ - "Anti-ligature construction for behavioral health areas"
+ - "Security construction for detention and holding areas"
+ - "Security construction with an integral fire or smoke damper"
+default: "Not required"
+```
+
+### Anti-ligature construction shall present no exposed edge, projection, gap, or fastener head capable of anchoring a cord or fabric, and all exposed edges shall be radiused or chamfered and all fasteners recessed below the face.
+
+### Security construction shall be of heavy-gauge steel or stainless steel with a perforation pattern that passes the scheduled airflow while preventing the passage of contraband.
+
+### Devices in security and anti-ligature construction shall be secured with fasteners whose drive tool is not sold through general retail distribution, and two drive tools per fastener type shall be turned over to the Owner at Substantial Completion.
+
+### Where a device in security construction also serves as a fire or smoke damper, the assembly shall be listed to UL 555 or UL 555S as applicable to the rating of the assembly it penetrates.
+
+### Security and anti-ligature devices shall be attached to structure or to solid backing, not to the ceiling suspension system.
+
+# Device Scheduling and Ceiling Coordination {toc}
+
+## Each device shall be furnished for the tag, device type, face size, neck size, scheduled airflow, frame style, finish, and integral damper listed in the air outlet schedule. [[drawing: the air outlet schedule]]
+
+## Device locations, orientation, and position within the ceiling module shall be as shown on the reflected ceiling plan. [[drawing: the reflected ceiling plan]]
+
+## Face size, neck size, and airflow are project-sized quantities established device by device during design; the template values in this standard are the criteria those sizes are chosen to satisfy, not the sizes themselves. {note}
+
+## The Contractor shall participate in overhead coordination for every ceiling area, resolving the positions of devices, luminaires, sprinkler heads, speakers, and detectors against one another before any ceiling suspension is installed.
+
+## Relocating a device after the ceiling grid is set to clear a conflict leaves it out of the module and visibly out of line with its neighbors, which is why the conflict has to be found on the coordination drawing rather than in the field. {note}
+
+## Where a conflict cannot be resolved without moving a device out of its scheduled position, the Contractor shall obtain the Engineer of Record's acceptance of the revised position before installing it.
+
+# Installation {toc}
+
+## Support of Devices in Suspended Ceilings {toc}
+
+### Each device installed in a suspended ceiling shall be independently supported from the building structure above.
+
+### The lay-in flange of a device shall locate the device within the ceiling module and shall not carry the weight of the device or of the duct connected to it.
+
+### Not less than two supports shall be provided from structure to the device frame at diagonally opposite corners.
+
+### Where the installed weight of a device including its connected duct exceeds 20 lb, supplementary support shall be provided in accordance with the manufacturer's published support detail.
+
+### Devices shall be installed plumb and square within the ceiling module, with the face flush with the surrounding ceiling surface within 1/16 in.
+
+## Devices in Hard-Surface Ceilings and Walls {toc}
+
+### Openings in gypsum board, plaster, wood, and masonry surfaces shall be cut to the manufacturer's published rough opening dimension.
+
+### An opening cut oversize shall be reframed and the surface repaired to match the adjacent finish, and shall not be closed with sealant, shims, or an oversized border.
+
+### Plaster frames shall be furnished by the device manufacturer and shall be set to the finished plaster elevation before plaster work begins.
+
+### The Contractor shall notify the plastering trade of each plaster frame location and elevation before the frames are set.
+
+### Wall-mounted devices in an accessible route shall be installed so that no part of the device projects into the route beyond the limit permitted by ICC A117.1.
+
+## Duct Connection at the Device {toc}
+
+### Each device shall be connected to the duct system through a sheet metal collar matching the device neck dimension.
+
+### The joint between the collar and the device neck shall be mechanically fastened by band clamp, screws, or flange, and shall be sealed to the seal class established for the duct system in [[sync/hvac-ductwork]].
+
+### Flexible duct connections at devices shall comply with the support, bend radius, and maximum length provisions of [[sync/hvac-ductwork]].
+
+### The last section of duct entering a device neck shall be straight and concentric with the neck for not less than one neck diameter, unless an equalizing grid is provided at that device.
+
+### A flexible duct compressed, kinked, or bent through a radius tighter than its rated minimum at the device connection loses a large fraction of the airflow the branch was sized to deliver, and no amount of balancing at the device recovers it. {note}
+
+## Sealing at the Device Frame {toc}
+
+### Where a supply device is installed in a ceiling whose plenum serves as a return air path, the device frame shall be sealed continuously to the ceiling surface.
+
+### An unsealed supply device frame in a return plenum lets conditioned supply air pass directly around the border into the return without ever entering the room, which appears at balancing as a device that cannot reach its scheduled airflow. {note}
+
+### Where a device is installed in a ducted-return ceiling, the frame shall be seated on a continuous gasket or sealant bead so that no gap is visible at the border and no flanking sound path is left around the device.
+
+## Protection During Construction {toc}
+
+### Devices shall remain in the manufacturer's packaging until the ceiling or wall surface in which they are installed is complete.
+
+### Devices installed before adjacent finishing work is complete shall be covered and protected from dust, paint overspray, plaster, and impact.
+
+### Devices soiled during construction shall be cleaned by a method the manufacturer approves for the finish supplied.
+
+### Abrasive cleaning and solvent cleaning that dulls, softens, or removes the specified finish shall not be used.
+
+### Where a device cannot be restored to match the adjacent devices in the same visible area, it shall be replaced at the expense of the party responsible for the damage.
+
+### Where the parties disagree whether a cleaned device matches the adjacent devices, the Architect shall make the initial determination.
+
+# Field Testing and Balancing {toc}
+
+## Airflow Balancing at Devices {toc}
+
+### The airflow at each device shall be measured and adjusted to the scheduled value within the tolerance indicated in the datasheet, applied as a plus-or-minus band about the scheduled airflow.
+
+```datasheet
+label: Air Balance Tolerance at Each Device
+type: range
+unit: '%'
+min: 5
+max: 20
+setpoints: [5, 10, 15, 20]
+default: 10
+```
+
+### Balancing shall be performed with the system clean, the design filter media installed, all ceiling tiles in place, and every device in its final installed condition.
+
+### The balancing contractor shall set each integral damper, pattern controller, and adjustable core, and shall record the final position of each.
+
+### Measured airflow, final damper position, and final pattern setting shall be reported for each device in accordance with [[sync/testing-adjusting-and-balancing]].
+
+### Where a device cannot be brought within tolerance by adjustment at the device and at its branch damper, the balancing contractor shall report the condition to the Engineer of Record rather than throttling the device further.
+
+## Verification of Discharge Pattern {toc}
+
+### In spaces with a non-rectangular plan, a ceiling height above 12 ft, or a stated comfort requirement, the discharge pattern at each supply outlet shall be verified by smoke visualization or by anemometer traverse after balancing is complete.
+
+### Devices with an adjustable pattern shall be reset as required to produce the pattern the design assumed.
+
+### A device with a factory-fixed pattern that does not produce the design pattern shall be replaced with a device of the correct pattern at no cost to the Owner.
+
+## Field Verification of Sound Levels {toc}
+
+### Field verification of device-generated sound shall be as indicated in the datasheet.
+
+```datasheet
+label: Field Verification of Device-Generated Sound
+type: radio
+options:
+ - "Not required"
+ - "Required in spaces with a sound limit of NC 30 or lower"
+ - "Required in a representative space of each space type"
+ - "Required in every space served by the system"
+default: "Not required"
+```
+
+### Where field verification is required, sound pressure shall be measured in octave bands at the listener position with the system operating at the scheduled airflow and with the space otherwise quiet, and the result shall be evaluated to ANSI/ASA S12.2.
+
+### Where a measured level exceeds the specified limit and the excess is attributable to the device or its installation, the Contractor shall correct the condition and shall bear the cost of re-measurement.
+
+### Where a measured level exceeds the specified limit and the excess is attributable to a sound source outside the scope of this standard, the Engineer of Record shall determine the responsible scope.
+
+## Ceiling Smudge Inspection {toc}
+
+### After not less than 90 days of system operation following occupancy, the ceiling surface around each ceiling-mounted supply outlet shall be inspected for smudging.
+
+### Smudging is airborne dust deposited on the ceiling where the supply jet entrains room air past the outlet face. The pattern it leaves is a record of the actual discharge direction, so it exposes a pattern controller that has shifted, a damaged face, and a room dust load higher than the design assumed. {note}
+
+### Where smudging is found, the Contractor shall clean the affected ceiling surface and shall report the discharge pattern the smudge indicates to the Engineer of Record.
+
+### Where the smudge pattern shows that a device is discharging other than as set at balancing, the device shall be reset and the cause corrected under the warranty.
+
+# Delivery, Storage, and Handling {toc}
+
+## Devices shall be delivered in the manufacturer's packaging with each unit marked with its project device tag.
+
+## Devices shall be stored indoors in a clean, dry, weather-protected space until installation.
+
+## Devices shall not be stacked in a manner that deforms a face panel or racks a frame.
+
+## Removable cores, pattern controllers, and loose accessories shall remain in their packaging until immediately before installation.
+
+## Where the building is not dried in or the ceiling is not ready to receive devices, the Contractor shall hold the devices in protected storage rather than installing them.
+
+# Device Identification {toc}
+
+## Each installed device shall correspond to the device tag shown in the air outlet schedule.
+
+## Where an installed device differs from the scheduled device, the as-built device schedule shall record the device actually installed.
+
+## Identification of devices for the Owner's maintenance staff shall be by the air outlet schedule and the as-built mechanical drawings.
+
+## Labels, tags, and markings applied to the exposed face of a device shall be removed before Substantial Completion.
+
+# Warranty {toc}
+
+## The Contractor shall warrant the devices and their installation, including frame fit, alignment, integral damper operation, and core retention, for the period indicated in the datasheet, beginning at the date of Substantial Completion.
+
+```datasheet
+label: Device and Installation Warranty Period
+type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 3, 5]
+default: 1
+```
+
+## The Contractor shall warrant the exposed finish against peeling, blistering, chalking, and color shift for the period indicated in the datasheet, beginning at the date of Substantial Completion.
+
+```datasheet
+label: Exposed Finish Warranty Period
+type: range
+unit: years
+min: 1
+max: 10
+setpoints: [1, 2, 3, 5, 10]
+default: 1
+```
+
+## Warranty coverage shall include the cost of removing and reinstalling the ceiling, wall, and duct work disturbed to reach a device being repaired or replaced, and the cost of repairing collateral damage caused by that work.
+
+## Where a device is repaired or replaced under warranty, the repaired or replacement device shall carry a fresh warranty of the full original period from the date of the repair, or the remainder of the original period, whichever ends later.
+
+## Finish failure on a device exposed to direct sunlight through glazing shall be covered where the exposure is within the limit the manufacturer publishes for the finish supplied.
+
+# Spare Parts {toc}
+
+## The Contractor shall deliver the following to the Owner at Substantial Completion:
+
+- One spare core for each removable-core outlet model installed
+- One spare pattern controller for each adjustable-pattern outlet model installed
+- Two operator keys or tools for each integral damper access type installed
+- Touch-up coating in each specified color, not less than 4 oz per color
+- Two drive tools for each security or anti-ligature fastener type installed
+
+```datasheet
+label: Spare Parts at Substantial Completion
+type: checkbox
+options:
+ - "One spare core for each removable-core outlet model"
+ - "One spare pattern controller for each adjustable-pattern outlet model"
+ - "Two operator keys or tools for each integral damper access type"
+ - "Touch-up coating in each specified color, 4 oz minimum"
+ - "Two drive tools for each security or anti-ligature fastener type"
+default:
+ - "One spare core for each removable-core outlet model"
+ - "One spare pattern controller for each adjustable-pattern outlet model"
+ - "Two operator keys or tools for each integral damper access type"
+ - "Touch-up coating in each specified color, 4 oz minimum"
+```
+
+## Spare parts shall be delivered in labeled containers identifying the device model, the device tags they serve, and the date of delivery.
+
+## Touch-up coating for a custom color shall be ordered with the original device order so that the touch-up supply and the installed devices come from the same coating batch.