Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Acoustic Ceiling Clouds and Baffles
…136 unchanged lines
## The installer shall have a minimum of three years of documented experience installing free-hanging acoustic ceiling systems of comparable scope and complexity.
−## Acoustic performance ratings shall be substantiated by test reports from an independent laboratory accredited for the applicable test method. {note}
+## Acoustic performance ratings shall be substantiated by test reports from an independent laboratory accredited for the applicable test method.
## Manufacturer product literature alone is not acceptable substantiation for fire classification or acoustic performance; independent test reports are required. {note}
…13 unchanged lines
## A baffle exposes multiple faces to the room, so its absorption is a property of the whole object, not of a projected flat area. NRC is a per-square-foot metric valid only for flat panel surfaces; applying NRC to a baffle misstates its true absorption capacity and corrupts the room acoustic calculation. The sabin — one square foot of perfect absorber, named for Wallace Sabine — is the correct unit for object-based elements. {note}
−## Specifying a minimum NRC without also specifying coverage percentage or total sabins is insufficient. An under-populated field of high-NRC panels will not meet the acoustic goal; the specification shall therefore require an acoustic calculation demonstrating the target reverberation time or absorption. {note}
+## Specifying a minimum NRC without also specifying coverage percentage or total sabins is insufficient. An under-populated field of high-NRC panels will not meet the acoustic goal; the specification shall therefore require an acoustic calculation demonstrating the target reverberation time or absorption.
## Thicker elements absorb more low-frequency energy below 500 Hz. Where low-frequency control drives the design, increasing panel or baffle thickness is more effective than adding thin high-NRC area. {note}
…82 unchanged lines
### The element substrate material shall be selected to satisfy the acoustic, weight, moisture, cleanability, and appearance requirements of each space.
−### Substrate selection is the primary material decision and trades off against several properties at once. Mineral fiber offers strong absorption and Class A fire performance at higher weight; fiberglass is lighter with high absorption; polyester fiber is the lightest and most moisture-resistant and is favored in hospitality and education; open-cell foam is light and formable but often requires a coating for Class A; fabric-wrapped rigid board provides the highest absorption and the most refined finish. {note}
−
```datasheet
label: Substrate Material
…8 unchanged lines
```
+### Substrate selection is the primary material decision and trades off against several properties at once. Mineral fiber offers strong absorption and Class A fire performance at higher weight; fiberglass is lighter with high absorption; polyester fiber is the lightest and most moisture-resistant and is favored in hospitality and education; open-cell foam is light and formable but often requires a coating for Class A; fabric-wrapped rigid board provides the highest absorption and the most refined finish. {note}
+
### The element nominal thickness shall be specified:
…27 unchanged lines
### The element orientation and geometry shall be specified for each treated area.
−### Geometry is both an acoustic and an architectural decision. Horizontal floating clouds present a downward-facing absorptive plane and read as a discontinuous ceiling; vertical baffles and blades present absorptive faces to lateral sound paths and read as a rhythmic louvered field; shaped or custom canopies serve feature spaces. The chosen geometry drives the suspension method and the sprinkler coordination strategy. {note}
−
```datasheet
label: Element Geometry
…7 unchanged lines
```
+### Geometry is both an acoustic and an architectural decision. Horizontal floating clouds present a downward-facing absorptive plane and read as a discontinuous ceiling; vertical baffles and blades present absorptive faces to lateral sound paths and read as a rhythmic louvered field; shaped or custom canopies serve feature spaces. The chosen geometry drives the suspension method and the sprinkler coordination strategy. {note}
+
### The standard module size shall be specified for rectangular clouds:
…23 unchanged lines
```
−### Custom CNC-cut or fabric-wrapped shapes shall be scheduled with adequate procurement float, as these elements typically carry a 6 to 12 week lead time and ordering them as a standard bid item without schedule allowance causes delivery delays. {note}
+### Custom CNC-cut or fabric-wrapped shapes shall be scheduled with adequate procurement float, as these elements typically carry a 6 to 12 week lead time and ordering them as a standard bid item without schedule allowance causes delivery delays.
## Edge and Finish Treatment {toc}
### The element edge treatment shall be specified for each element type.
−### Raw-cut mineral fiber and fiberglass edges are fragile and chip at corners during handling and installation. Omitting a specified edge detail leads to damaged elements and field-reported finish deficiencies; the edge treatment is therefore a required selection, not an afterthought. {note}
−
```datasheet
label: Edge Treatment
…7 unchanged lines
```
+### Raw-cut mineral fiber and fiberglass edges are fragile and chip at corners during handling and installation. Omitting a specified edge detail leads to damaged elements and field-reported finish deficiencies; the edge treatment is therefore a required selection, not an afterthought. {note}
+
### The element color shall be specified.
…10 unchanged lines
```
−### Custom colors and finishes deviate from standard white or off-white and alter lighting calculations; where a custom color is specified, the reflected-ceiling lighting design shall be coordinated to the actual LRV. {note}
+### Custom colors and finishes deviate from standard white or off-white and alter lighting calculations; where a custom color is specified, the reflected-ceiling lighting design shall be coordinated to the actual LRV.
# Suspension System {toc}
…5 unchanged lines
## The suspension system type shall be selected based on deck type, element weight, geometry, and seismic category.
−## Suspension method follows from the structure and the element. Aircraft-cable-and-eyebolt systems suit light clouds and baffles on most decks; carrier rail or track suits continuous baffle runs; rigid rod suits fixed-drop installations; a custom fabricated frame suits heavy or shaped canopies. The seismic category then determines whether standard hangers or engineered positive attachment is required. {note}
−
```datasheet
label: Suspension System Type
…7 unchanged lines
```
+## Suspension method follows from the structure and the element. Aircraft-cable-and-eyebolt systems suit light clouds and baffles on most decks; carrier rail or track suits continuous baffle runs; rigid rod suits fixed-drop installations; a custom fabricated frame suits heavy or shaped canopies. The seismic category then determines whether standard hangers or engineered positive attachment is required. {note}
+
## Suspension hardware shall be rated for a minimum of 1.5 times the element dead load.
…12 unchanged lines
## The suspension drop and structural attachment points are layout information that cannot be reduced to a single field value; their locations shall be coordinated and shown [[drawing: cloud and baffle suspension point layout]].
−## Lightweight polyester baffles can be dislodged or set swinging by supply-air jets from nearby diffusers. Where a baffle is within the throw of a diffuser, a lower attachment point shall be provided and the diffuser type and throw direction coordinated with the HVAC engineer. {note}
+## Lightweight polyester baffles can be dislodged or set swinging by supply-air jets from nearby diffusers. Where a baffle is within the throw of a diffuser, a lower attachment point shall be provided and the diffuser type and throw direction coordinated with the HVAC engineer.
# Sprinkler Coordination {toc}
…58 unchanged lines
## Element layout shall be coordinated with sprinklers, lighting, HVAC diffusers, and other overhead infrastructure before fabrication.
−## Integrated-LED cloud and canopy products require electrical rough-in that matches the element layout exactly. If the element layout is finalized after electrical rough-in, conduit and circuit locations must be relocated at significant cost; the cloud layout and the lighting rough-in shall be coordinated together. Luminaire and trim specification itself remains with the electrical division. {note}
+## Integrated-LED cloud and canopy products require electrical rough-in that matches the element layout exactly. If the element layout is finalized after electrical rough-in, conduit and circuit locations must be relocated at significant cost; the cloud layout and the lighting rough-in shall be coordinated together. Luminaire and trim specification itself remains with the electrical division.
−## HVAC diffuser discharge patterns shall be coordinated with baffle locations and attachment so that supply-air throw does not dislodge or destabilize lightweight elements. {note}
+## HVAC diffuser discharge patterns shall be coordinated with baffle locations and attachment so that supply-air throw does not dislodge or destabilize lightweight elements.
## The overhead coordination items requiring layout resolution shall be shown [[drawing: reflected ceiling plan with cloud, baffle, sprinkler, lighting, and diffuser coordination]].
…69 unchanged lines
unit: '% of installed'
```