Acoustic Insulation

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−---

−title: Acoustic Insulation

−category: Architectural

−toc_depth: 3

−description: >

− When to use: Sound-absorbing insulation installed within partition cavities, ceiling plenums, and floor/ceiling assemblies to attenuate airborne sound transmission between interior spaces in commercial, institutional, healthcare, hospitality, multi-family residential, and educational buildings. Covers unfaced mineral fiber (stone wool and slag wool), unfaced glass fiber batts and blankets, and mineral wool board used as cavity infill. Addresses material selection, density and thickness, integration with the host wall, ceiling, or floor assembly to achieve tested STC ratings, fire and smoke characteristics, noncombustibility, attachment in plenum and floor applications, and field verification of acoustic performance.

− Not intended for: Thermal-only insulation in building envelope assemblies (see [[sync/building-thermal-insulation]]); duct liner and duct wrap (see [[sync/hvac-ductwork]]); exterior acoustical wall panels, sound-absorbing ceiling tiles, or freestanding acoustic baffles; sound masking electronic systems; vibration isolation pads and seismic isolation; below-slab impact insulation for floor-floor IIC ratings as a standalone product (coordinate with floor assembly standard); firestopping at penetrations through rated assemblies (see [[sync/firestopping]]); and acoustic seals at door and frame perimeters (see [[sync/doors-frames-and-hardware]]).

−---

−

−# Scope {toc}

−

−## This standard governs the selection, specification, and installation of sound-absorbing insulation installed within concealed cavities of interior partitions, suspended ceiling plenums, and floor/ceiling assemblies for the purpose of attenuating airborne sound transmission between adjacent spaces. {note}

−## The materials covered are unfaced mineral fiber blanket and batt (stone wool and slag wool), unfaced glass fiber blanket and batt, and mineral fiber board, in the densities and thicknesses commonly used as cavity infill in commercial construction. {note}

−

−## Acoustic insulation is one component of an acoustic assembly. {note}

−## The sound transmission class (STC) of a partition or floor/ceiling is the property of the entire system — the gypsum board layers, the framing, the cavity insulation, the perimeter sealing, and any decoupling elements such as resilient channel, all combine to produce the tested rating. {note}

−

−## The Contractor shall install the insulation type, density, and thickness specified in the referenced tested assembly without substitution.

−

−## The Contractor shall coordinate the cavity infill with [[sync/gypsum-board-assemblies]] for partitions and with the applicable floor and ceiling specifications.

−

−## Substituting a different insulation density, thickness, or material than the one in the tested assembly can change the STC by several points and may push a partition below the design intent. {note}

−

−## Acoustic insulation in a stud cavity contributes to STC primarily by damping the cavity resonance: filling the cavity with porous, fibrous insulation introduces flow resistance that absorbs standing-wave energy, broadening and lowering the resonance and improving transmission loss across most of the speech frequency range. {note}

−

−## The acoustic mechanism is friction in the fiber matrix, not mass, which is why a 2.5 pcf and a 6.0 pcf stone wool batt produce nearly the same STC contribution in a typical stud-wall cavity; in most stud-wall and ceiling-plenum applications the density at which incremental improvement falls off is between 2.5 and 3.5 pcf. {note}

−

−## The Contractor shall coordinate with [[sync/gypsum-board-assemblies]] for the partition design number that drives material, density, and thickness selection.

−

−## The Contractor shall coordinate with [[sync/firestopping]] for penetration-firestopping where acoustic insulation occurs in fire-resistance-rated assemblies.

−

−## Where a single insulation product is intended to serve both thermal and acoustic purposes within the building envelope, the requirements of [[sync/building-thermal-insulation]] shall govern.

−

−## The Contractor shall coordinate with [[sync/doors-frames-and-hardware]] for acoustic seals and gasketing at door and frame perimeters in acoustically rated partitions, because door-frame leakage is the dominant flanking path in most rated rooms.

−

−# Referenced Standards {toc}

−

−## Materials and installation shall comply with the latest edition of each of the following standards adopted by the Authority Having Jurisdiction.

−

−| Standard | Title |

−|----------|-------|

−| ASTM C665 | Standard Specification for Mineral-Fiber Blanket Thermal Insulation for Light Frame Construction and Manufactured Housing (Type I unfaced applicable) |

−| ASTM C612 | Standard Specification for Mineral Fiber Block and Board Thermal Insulation |

−| ASTM C553 | Standard Specification for Mineral Fiber Blanket Thermal Insulation for Commercial and Industrial Applications |

−| ASTM C518 | Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus |

−| ASTM C411 | Standard Test Method for Hot-Surface Performance of High-Temperature Thermal Insulation |

−| ASTM C795 | Standard Specification for Thermal Insulation for Use in Contact with Austenitic Stainless Steel |

−| ASTM C1338 | Standard Test Method for Determining Fungi Resistance of Insulation Materials and Facings |

−| ASTM E84 | Standard Test Method for Surface Burning Characteristics of Building Materials |

−| ASTM E90 | Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements |

−| ASTM E413 | Classification for Rating Sound Insulation |

−| ASTM E1414 | Standard Test Method for Airborne Sound Attenuation Between Rooms Sharing a Common Ceiling Plenum |

−| ASTM E336 | Standard Test Method for Measurement of Airborne Sound Attenuation Between Rooms in Buildings |

−| ASTM E1332 | Standard Classification for Rating Outdoor-Indoor Sound Attenuation |

−| ASTM E136 | Standard Test Method for Assessing Combustibility of Materials Using a Vertical Tube Furnace at 750 °C |

−| IBC | International Building Code (current edition adopted by jurisdiction) |

−| NFPA 101 | Life Safety Code (corridor and separation wall acoustic and fire requirements) |

−| UL Fire Resistance Directory | UL Fire-Resistance Rated Systems |

−

−## Where the contract documents, the adopted building code, or a referenced standard impose conflicting requirements, the more stringent shall govern unless the Architect of Record directs otherwise in writing.

−

−# Submittals {toc}

−

−## Action Submittals {toc}

−

−### The Contractor shall submit the following for the Architect's review before procurement and installation:

−

−- Product data for each acoustic insulation type, including material composition (stone wool, slag wool, or glass fiber), nominal density, thickness range, dimensional tolerances, and applicable ASTM product designation

−- ASTM E84 surface burning test report for each insulation product, showing flame spread index (FSI) and smoke developed index (SDI)

−- ASTM E136 noncombustibility classification where required by the project's construction type or by the applicable fire-resistance design number

−- Third-party laboratory test reports per ASTM E90 demonstrating the STC contribution of the proposed insulation in assemblies matching the project's tested partition designs, where the cavity-fill material is the specific insulation product proposed

−- Identification of the specific UL or GA-600 design number under which the insulation will be used, cross-referenced to each acoustically and fire-rated partition type designation

−- Manufacturer's installation instructions, including friction-fit retention guidance, recommendations for plenum and floor cavity attachment, and any limitations on cavity orientation

−- Sample of each insulation product proposed, minimum 12 inches × 12 inches, for verification of density, facing (if any), and dimensional consistency

−

−```datasheet

−label: Action Submittals Required

−type: checkbox

−options:

− - "Product data for each acoustic insulation type"

− - "ASTM E84 surface burning test report"

− - "ASTM E136 noncombustibility classification (where required)"

− - "ASTM E90 laboratory STC test reports for cited assemblies"

− - "Fire-resistance design number cross-reference schedule"

− - "Manufacturer installation instructions"

− - "Product samples"

−default: "Product data for each acoustic insulation type"

−```

−

−### The Contractor shall submit the action submittal items listed above for the Architect's review before procurement and installation.

−

−### Installation of acoustic insulation in any rated assembly shall not begin until the corresponding submittals have been reviewed and returned.

−

−## Closeout Submittals {toc}

−

−### The Contractor shall provide the following at project closeout:

−

−- Certificate of compliance signed by the Contractor stating that all acoustic insulation was installed in conformance with the approved submittals, manufacturer's instructions, and this standard

−- Field test reports for STC or noise isolation class (NIC) verification testing where specified

−- Warranty documentation for products carrying a manufacturer warranty

−

−```datasheet

−label: Closeout Submittals Required

−type: checkbox

−options:

− - "Certificate of compliance signed by the Contractor"

− - "Field test reports for STC or NIC verification (where specified)"

− - "Warranty documentation for products carrying a manufacturer warranty"

−default: [Certificate of compliance signed by the Contractor, Field test reports for STC or NIC verification (where specified), Warranty documentation for products carrying a manufacturer warranty]

−```

−

−### The Contractor shall provide the closeout submittal items listed above at project closeout.

−

−# Quality Assurance {toc}

−

−## Installer Qualifications {toc}

−

−### Insulation contributes meaningfully to STC only when it fills the cavity continuously and without compression. {note}

−

−### Acoustic insulation shall be installed by workers experienced in commercial cavity-insulation work and familiar with the requirements of tested acoustic and fire-resistance design numbers.

−

−### Installers shall be trained in the splitting, fitting, and friction-fit techniques that achieve complete cavity coverage around wiring, blocking, electrical boxes, and other obstructions.

−

−## Pre-Installation Coordination {toc}

−

−### Before acoustic insulation installation begins in rated assemblies, the Contractor shall confirm with the Architect that the insulation type, density, and thickness match the specific tested assembly design number referenced on the drawings.

−

−### Substitution of a lighter density, a different fiber type, or a thinner product than the tested configuration shall not be made without written approval.

−

−### The Contractor shall coordinate the insulation work with the framing, electrical rough-in, plumbing, and other trades whose cavity penetrations will be in place before the cavity is closed.

−

−### Insulation installed before all in-cavity work is complete is invariably disturbed and shall be inspected after final rough-in.

−

−## Field Inspection of Rated Assemblies {toc}

−

−### Acoustic insulation in fire-resistance-rated or acoustically rated assemblies shall be available for inspection by the Authority Having Jurisdiction and the Owner's representative before the second face of the partition is closed with gypsum board.

−

−### The Contractor shall not close any rated assembly cavity until the cavity insulation has been inspected and released, or until written permission to proceed has been issued.

−

−### Pre-Closing Inspection of Cavity Insulation {toc}

−

−```datasheet

−label: Pre-Closing Inspection of Cavity Insulation

−type: radio

−options:

− - "Required for all rated assemblies"

− - "Required for STC 50 and higher assemblies only"

− - "Not required (non-rated assemblies)"

−default: "Required for all rated assemblies"

−```

−

−## Listing and Labeling {toc}

−

−### All acoustic insulation products shall bear the manufacturer's label identifying the product name, the applicable ASTM standard, the type or class designation, and the nominal density.

−

−### Labels shall remain on bundles delivered to site and on at least one batt from each opened bundle until installation is complete.

−

−### Unlabeled or unidentifiable insulation shall be rejected.

−

−# Environmental and Service Conditions {toc}

−

−## Temperature and Humidity at Installation {toc}

−

−### Acoustic insulation may be installed at any temperature within the manufacturer's stated range and is not affected by ambient humidity in the same way that joint compound or adhesive products are.

−

−### Insulation shall not be installed against wet substrates or in cavities subject to active water intrusion.

−

−### Mineral fiber and glass fiber that becomes saturated loses dimensional stability and shall be removed and replaced.

−

−### Drying wet insulation in place is not acceptable, because residual moisture in the fiber matrix supports microbial growth and the insulation typically does not return to its installed dimension. {note}

−

−## Service Conditions {toc}

−

−### Acoustic cavity insulation is intended for installation in dry, conditioned interior spaces. {note}

−### Use of these products in cavities subject to repeated wetting, condensation, or freeze-thaw cycling is outside the scope of this standard. {note}

−

−### Where the building envelope assembly is also the host for acoustic insulation, vapor management shall follow [[sync/building-thermal-insulation]] and the higher-density mineral wool products typical of envelope use shall be specified.

−

−## Fungi Resistance {toc}

−

−### Mineral fiber and glass fiber insulation are inherently inorganic and do not provide food for fungal growth; however, contamination of the fiber surface by dust, organic debris, or moisture can support growth on the surface, so maintaining a dry, clean cavity is the primary defense. {note}

−

−### Acoustic insulation products specified for use in healthcare, food-service, and other moisture-sensitive occupancies shall be tested for fungi resistance per ASTM C1338 and shall not support fungal growth under the test conditions.

−

−### Fungi Resistance Documentation {toc}

−

−```datasheet

−label: Fungi Resistance Documentation

−type: radio

−options:

− - "ASTM C1338 test report required"

− - "Manufacturer certification of inorganic composition acceptable"

− - "Not required"

−default: "Manufacturer certification of inorganic composition acceptable"

−```

−

−# General Material Requirements {toc}

−

−## All acoustic insulation shall be new, dry, undamaged, and free of compression set, oil, dust, or other contamination at time of installation.

−

−## Bundles that have been wetted, crushed in transit, or stored improperly shall be inspected and replaced where the fiber matrix has been disturbed.

−

−## Insulation shall be stored indoors in a dry, climate-controlled location, off the ground, and protected from weather, mechanical damage, and UV exposure until immediately before installation.

−

−## Plastic shipping wrap shall remain in place until the bundle is brought to its point of installation.

−

−# Stone Wool (Mineral Wool, Rock Wool) {toc}

−

−## Stone wool insulation is manufactured by melting basalt or other igneous rock together with a binder and spinning the molten material into fine fibers. {note}

−## The resulting product is inorganic, noncombustible, dimensionally stable at elevated temperature, and naturally water-shedding rather than water-absorbing. {note}

−

−## Stone wool batt and blanket for cavity-infill acoustic use shall conform to ASTM C665 (Type I, unfaced) where used in light-frame stud cavities, or to ASTM C553 for industrial and commercial blanket applications.

−

−## Mineral wool board (semi-rigid and rigid) shall conform to ASTM C612.

−

−## Stone wool is the default acoustic cavity-fill material for commercial gypsum-board partition assemblies in this standard because of its effective acoustic absorption at modest densities, noncombustibility per ASTM E136, friction-fit retention in vertical cavities, dimensional stability, and resistance to settling. {note}

−

−## Stone wool batts are dimensionally stiffer than glass fiber and hold their shape in tall partition cavities, masonry cavity walls, and ceiling-plenum applications where glass fiber would sag or compress over time. {note}

−

−# Slag Wool {toc}

−

−## Slag wool is manufactured from blast furnace slag using the same melt-and-spin process as stone wool. {note}

−## The fiber properties, density range, and acoustic performance are similar to stone wool, and slag wool products in the U.S. market are typically marketed under the broader "mineral wool" designation alongside stone wool. {note}

−

−## Slag wool shall conform to the same ASTM C665, C553, or C612 designations that apply to stone wool products and may be used wherever stone wool is specified, unless the contract documents specifically require stone wool.

−

−## Where the project specification or design number cites "mineral wool" without further qualification, either stone wool or slag wool meeting the cited ASTM standard is acceptable.

−

−# Glass Fiber (Fiberglass) {toc}

−

−## Glass fiber insulation is manufactured by melting silica sand and recycled glass and spinning the molten material into fine fibers, bound together with a binder resin. {note}

−## Glass fiber is the most economical acoustic cavity-fill material and is appropriate for the majority of non-rated and lower-STC commercial partitions. {note}

−

−## Unfaced glass fiber batt and blanket for cavity-infill acoustic use shall conform to ASTM C665 (Type I, unfaced) for light-frame construction or to ASTM C553 for commercial and industrial blanket.

−

−## Faced glass fiber products that include kraft or foil facings introduce combustible material and are not appropriate where ASTM E136 noncombustibility is required.

−

−## Glass fiber batts in low-density configurations (0.5 to 1.5 pcf) are less dimensionally stiff than mineral wool and may sag over time in tall vertical cavities or in plenum applications unless they are mechanically retained. {note}

−

−## Heavier-density glass fiber blanket products (2.0 pcf and above) approach mineral wool in dimensional stability and are appropriate for most commercial partition cavities. {note}

−

−## Material and Designation Selection {toc}

−

−```datasheet

−label: Acoustic Insulation Material

−type: radio

−options:

− - "Stone wool (basalt mineral wool)"

− - "Slag wool"

− - "Glass fiber (fiberglass)"

−default: "Stone wool (basalt mineral wool)"

−```

−

−```datasheet

−label: ASTM Product Designation

−type: radio

−options:

− - "ASTM C665 Type I (unfaced batt and blanket, light frame)"

− - "ASTM C553 (commercial/industrial blanket)"

− - "ASTM C612 (mineral fiber block and board)"

−drawing_ref: true

−default: "ASTM C665 Type I (unfaced batt and blanket, light frame)"

−```

−

−# Facing {toc}

−

−## Vapor-retarder facings (kraft, foil, or vinyl) interrupt the porous flow path that produces acoustic absorption, have a small but measurable effect on the cavity's transmission loss, and introduce combustible material into the cavity that is generally not compatible with the noncombustibility requirements of rated assemblies. {note}

−

−## Acoustic cavity-fill insulation in interior partitions, ceiling plenums, and floor cavities shall be unfaced.

−

−## Where vapor management is required by the assembly, the Contractor shall coordinate with [[sync/building-thermal-insulation]] for the placement of a separate vapor retarder layer and shall use an unfaced acoustic product for the cavity-fill function.

−

−## Insulation Facing {toc}

−

−```datasheet

−label: Insulation Facing

−type: radio

−options:

− - "Unfaced (standard for cavity acoustic use)"

− - "Foil-faced (only where vapor retarder integration is specifically required)"

− - "Kraft-faced (only where vapor retarder integration is specifically required)"

−default: "Unfaced (standard for cavity acoustic use)"

−```

−

−# Density and Thickness {toc}

−

−## Density Selection {toc}

−

−### For acoustic cavity-fill in stud-framed partitions, ceiling plenums, and floor/ceiling assemblies, the relationship between density and STC contribution flattens above approximately 2.5 pcf. {note}

−

−### The default density for general acoustic partition infill shall be 3.0 pcf stone wool, which provides the acoustic flow resistance required for full cavity damping without the cost and weight penalty of heavier products.

−

−### Lower densities (1.5 to 2.5 pcf) are acceptable for non-rated and moderately rated assemblies (up to STC 45) and are commonly used with glass fiber products.

−

−### Higher densities (4.0 to 6.0 pcf) shall be specified where the tested assembly design number requires that density, where the insulation also serves a fire-resistance protection role, or where the insulation will be exposed to elevated temperatures requiring documented performance per ASTM C411.

−

−### Nominal Density Selection {toc}

−

−```datasheet

−label: Nominal Density

−type: select

−unit: pcf

−options:

− - "1.5 pcf (glass fiber, non-rated and STC ≤ 40 partitions)"

− - "2.5 pcf (stone wool or glass fiber, STC up to 45)"

− - "3.0 pcf (stone wool, standard commercial partition default)"

− - "4.0 pcf (stone wool, fire-rated or higher-STC assemblies)"

− - "6.0 pcf (stone wool board, semi-rigid applications)"

−drawing_ref: true

−default: "3.0 pcf (stone wool, standard commercial partition default)"

−```

−

−## Thickness Selection {toc}

−

−### The default thickness of cavity-fill acoustic insulation shall be the full depth of the stud cavity, runner to runner.

−

−### Partial-fill insulation reduces the acoustic benefit, because the unfilled portion of the cavity continues to behave as an air spring and supports the resonance the insulation is intended to suppress. {note}

−

−### Additional thickness beyond the cavity depth provides no benefit and shall not be installed, because compressed insulation in a thinner cavity than its nominal dimension performs no better than insulation matched to the cavity depth and may deflect the framing or interfere with face-board attachment.

−

−### Cavity Fill and Thickness Selection {toc}

−

−```datasheet

−label: Cavity Fill Approach

−type: radio

−options:

− - "Full-depth fill (matches stud or joist depth) — default"

− - "Partial-fill (specific tested assembly only)"

−drawing_ref: true

−default: "Full-depth fill (matches stud or joist depth) — default"

−```

−

−```datasheet

−label: Nominal Thickness

−type: select

−unit: in

−options:

− - "1-1/2 in (2-1/2 in stud depth, partial use)"

− - "2-1/2 in (2-1/2 in stud cavity, full fill)"

− - "3-1/2 in (3-5/8 in stud cavity, full fill)"

− - "4 in (4 in stud cavity, full fill)"

− - "6 in (6 in stud cavity, full fill)"

−drawing_ref: "partition type schedule"

−default: "3-1/2 in (3-5/8 in stud cavity, full fill)"

−```

−

−# Acoustic Performance {toc}

−

−## Mechanism {toc}

−

−### The acoustic benefit of cavity insulation derives from porous absorption — the conversion of acoustic energy to heat as air oscillates through the fiber matrix. {note}

−### This mechanism is most effective in the speech-intelligibility frequency range (approximately 125 Hz to 4000 Hz) that drives the STC rating. {note}

−

−### The insulation does not add mass, does not stiffen the partition, and does not decouple the two face layers; those functions are performed by the gypsum board, the framing, and accessories such as resilient channel. {note}

−

−### In a typical single-stud gypsum-board partition with two layers of 5/8-inch board on each side and 3-1/2-inch stone wool fill, the cavity insulation contributes approximately 4 to 7 STC points compared to the same partition with an empty cavity. {note}

−

−## STC Contribution {toc}

−

−### A correctly executed full-cavity-fill of unfaced mineral fiber raises a typical commercial partition's STC by 4 to 7 points. {note}

−### The benefit is reduced where the insulation is partially compressed, partially missing, or sagging. {note}

−

−### Field surveys consistently identify incomplete cavity fill as the single most common cause of partitions that test below their design STC. {note}

−

−### Specified Partition Rating and Tested Assembly Reference {toc}

−

−```datasheet

−label: Specified Partition STC Rating

−type: select

−options:

− - "Not rated (no acoustic insulation required)"

− - "STC 40"

− - "STC 45"

− - "STC 50"

− - "STC 55"

− - "STC 60 or higher"

−drawing_ref: true

−default: "STC 45"

−```

−

−```datasheet

−label: Tested Assembly Reference

−type: radio

−options:

− - "GA-600 sound-rated design"

− - "UL classified design with acoustic data"

− - "Published independent laboratory ASTM E90 test report"

− - "Not applicable (non-rated assembly)"

−drawing_ref: true

−default: "GA-600 sound-rated design"

−```

−

−## Plenum and Ceiling-to-Ceiling Attenuation {toc}

−

−### Where partitions terminate at the suspended ceiling rather than extending to the structure above, sound passes over the partition through the shared ceiling plenum. {note}

−### The plenum-attenuation performance of the combined ceiling-and-partition is tested per ASTM E1414 and is reported as the ceiling attenuation class (CAC). {note}

−

−### Where the partition is intended to provide meaningful acoustic separation, the partition shall be extended to the structure above and the plenum-flanking path eliminated.

−

−### Where the partition terminates at the ceiling, the plenum portion shall receive a sound-isolating treatment specified on the drawings, which may include batts laid over adjacent ceiling tiles on each side of the partition, or a plenum barrier extending from the top of the partition to the deck above.

−

−### Partition Termination and Plenum Treatment {toc}

−

−```datasheet

−label: Partition Termination

−type: radio

−options:

− - "Deck-to-deck (partition extends to structure)"

− - "Ceiling height (terminates at suspended ceiling)"

− - "Ceiling height with plenum barrier above"

−drawing_ref: true

−default: "Deck-to-deck (partition extends to structure)"

−```

−

−```datasheet

−label: Plenum Acoustic Treatment (if partition terminates at ceiling)

−type: radio

−options:

− - "Batt insulation laid over adjacent tiles each side of partition"

− - "Continuous plenum barrier from top of partition to deck"

− - "None (no special treatment)"

− - "Not applicable (deck-to-deck partition)"

−drawing_ref: true

−default: "Not applicable (deck-to-deck partition)"

−```

−

−# Fire and Smoke Performance {toc}

−

−## General Fire Requirements {toc}

−

−### Acoustic insulation installed in fire-resistance-rated partition or ceiling assemblies shall be the type, density, and thickness specified in the tested design.

−

−### Substituting a different product can invalidate the rating. {note}

−

−### Mineral wool products are commonly required in higher-hour rated assemblies because their dimensional stability at elevated temperature contributes to the assembly's continued performance during a fire test; glass fiber products are acceptable in many lower-hour rated assemblies and in non-rated partitions. {note}

−

−## Surface Burning {toc}

−

−### Unfaced mineral wool and unfaced glass fiber typically achieve a Class A classification (FSI ≤ 25, SDI ≤ 50) without difficulty because the inorganic fiber does not propagate flame across its surface. {note}

−

−### Acoustic insulation shall be tested per ASTM E84 for surface burning characteristics.

−

−### Class A classification is the default and is required for all interior cavity-fill applications regulated by the IBC.

−

−### ASTM E84 Surface Burning Classification {toc}

−

−```datasheet

−label: ASTM E84 Surface Burning Classification

−type: radio

−options:

− - "Class A — FSI ≤ 25, SDI ≤ 50 (required)"

− - "Class B — FSI 26–75 (not acceptable for cavity-fill in rated assemblies)"

− - "Not applicable (product not exposed to interior)"

−default: "Class A — FSI ≤ 25, SDI ≤ 50 (required)"

−```

−

−## Noncombustibility {toc}

−

−### Stone wool, slag wool, and unfaced glass fiber typically meet ASTM E136 because the inorganic fiber and any small fraction of organic binder are below the combustibility thresholds in the test. {note}

−

−### Where the project's construction type or the cited fire-resistance design requires noncombustible materials, the acoustic insulation shall be classified noncombustible per ASTM E136.

−

−### Faced products (kraft or foil facings) contain organic material, do not meet ASTM E136, and shall not be substituted where noncombustibility is required.

−

−### ASTM E136 Noncombustibility Requirement {toc}

−

−```datasheet

−label: ASTM E136 Noncombustibility Required

−type: radio

−options:

− - "Required (IBC Type I or II construction, or rated design requires)"

− - "Not required"

−drawing_ref: true

−default: "Required (IBC Type I or II construction, or rated design requires)"

−```

−

−## Hot Surface and Continuous Service Temperature {toc}

−

−### Mineral wool products are typically rated for continuous service temperatures of 1200 °F or higher; glass fiber products are typically rated for 350 °F. {note}

−### In ordinary partition cavities at room temperature, ASTM C411 documentation is not required. {note}

−

−### Where acoustic insulation will be in contact with surfaces operating above ambient temperature — for example, adjacent to recessed light fixtures, behind chimneys or flues, or in service-temperature applications — its performance shall be evaluated per ASTM C411.

−

−## Contact with Stainless Steel {toc}

−

−### This requirement is rare in cavity-fill acoustic applications but shall be addressed if specified.

−

−### Where insulation will be in direct contact with austenitic stainless steel, the product shall comply with ASTM C795 to limit leachable chlorides, fluorides, sodium, and silicates that could cause stress corrosion cracking of the stainless steel.

−

−# Accessories {toc}

−

−## Retention in Vertical Cavities {toc}

−

−### Mineral wool and stiff-blanket glass fiber batts in vertical stud cavities shall be retained by friction fit, with the batt width sized 1/2 to 1 inch wider than the stud spacing so the batt compresses slightly into the cavity and is held by friction against the stud faces.

−

−### In tall partitions (over 12 feet), in cavities exposed to vibration, or where settlement of softer glass fiber products is a concern, supplemental retention shall be provided.

−

−### Stud Cavity Retention Method {toc}

−

−```datasheet

−label: Stud Cavity Retention Method

−type: radio

−options:

− - "Friction fit (default for stone wool and stiff blanket products)"

− - "Friction fit + horizontal support strips at floor lines (tall cavities)"

− - "Insulation clips at cavity perimeter"

− - "Self-adhering insulation backing"

−drawing_ref: true

−default: "Friction fit (default for stone wool and stiff blanket products)"

−```

−

−## Retention in Ceiling and Floor Cavities {toc}

−

−### Insulation laid above suspended ceilings or installed within floor/ceiling joist cavities shall be retained against displacement and sag.

−

−### Insulation supports in floor/ceiling cavities shall be wire support rods, plastic mesh, or strapping installed at 18 inches on center maximum across the underside of the cavity.

−

−### Insulation laid above suspended ceiling tiles shall be sized to match the tile module so it bears on the grid rather than on the tile face.

−

−### Insulation that bears on the face of a thin tile may produce visible sag in the ceiling line over time. {note}

−

−### Floor/Ceiling Cavity Retention {toc}

−

−```datasheet

−label: Floor/Ceiling Cavity Retention

−type: radio

−options:

− - "Wire support rods at 18 in o.c. (standard for batts in floor joist cavities)"

− - "Plastic mesh or strapping at 18 in o.c."

− - "Self-adhering blanket"

− - "Not applicable"

−drawing_ref: true

−default: "Wire support rods at 18 in o.c. (standard for batts in floor joist cavities)"

−```

−

−## Mechanical Fasteners for Board Products {toc}

−

−### Mineral wool board installed within partition or ceiling cavities for high-performance acoustic applications shall be retained by mechanical impalement pins, adhesive, or wire ties as specified by the tested assembly.

−

−### Impalement pins shall be of length suitable to penetrate the board thickness and engage the substrate, and shall be capped with locking washers that hold the board against the substrate.

−

−### Mineral Wool Board Attachment {toc}

−

−```datasheet

−label: Mineral Wool Board Attachment

−type: radio

−options:

− - "Friction fit between studs (most common)"

− - "Impalement pins with locking washers"

− - "Adhesive applied to substrate"

− - "Wire ties through framing"

− - "Not applicable (batt or blanket product)"

−default: "Friction fit between studs (most common)"

−```

−

−# Installation {toc}

−

−## General Installation Requirements {toc}

−

−### Cavity-fill insulation is one of the most commonly compromised elements in partition construction because the work is concealed and feedback on its quality is slow. {note}

−

−### Acoustic insulation shall be installed after all rough-in work within the cavity is complete and inspected — including electrical conduit and boxes, plumbing, low-voltage cabling, in-wall bracing, and any required fire-blocking — and before the second face of the partition is closed with gypsum board.

−

−### The Contractor shall coordinate the timing of insulation installation so that no further trades require access to the cavity after insulation is in place.

−

−### Cavities that are reopened after insulation is installed shall be re-inspected and the insulation re-fitted.

−

−### The insulation shall fill the cavity continuously from runner to runner and from stud face to stud face without compression, gaps, or voids.

−

−### The Contractor shall treat the insulation work with the same care given to the visible face layers.

−

−## Splitting Around Obstructions {toc}

−

−### A batt simply folded behind a wire or compressed around an electrical box leaves a localized void that disproportionately reduces the partition's acoustic and fire performance. {note}

−

−### Wires, pipes, blocking, fire-stops, and electrical boxes within the cavity shall be accommodated by splitting the insulation so that both sides of the obstruction are filled.

−

−### The Contractor shall split each batt to the depth required to wrap the obstruction front and back, taking care to maintain full thickness on both sides.

−

−### Splitting of Insulation Around Cavity Obstructions {toc}

−

−```datasheet

−label: Splitting of Insulation Around Cavity Obstructions

−type: radio

−options:

− - "Required at all wires, pipes, blocking, fire-stops, and boxes"

− - "Discretionary"

−drawing_ref: true

−default: "Required at all wires, pipes, blocking, fire-stops, and boxes"

−```

−

−## Friction Fit and Sizing {toc}

−

−### Batts shall be sized 1/2 to 1 inch wider than the stud spacing so they compress slightly into the cavity and friction-fit between the studs.

−

−### Batts cut narrower than the cavity width shall not be force-fit by wedging; they shall be replaced with correctly sized batts.

−

−### Batts wider than 1 inch over the cavity width shall be trimmed, because excess width that buckles into the cavity creates internal voids and prevents the face board from sitting flush against the studs.

−

−### Batt Width Relative to Stud Spacing {toc}

−

−```datasheet

−label: Batt Width Relative to Stud Spacing

−type: radio

−options:

− - "Match stud spacing nominal width (16 in stud — 15 in batt; 24 in stud — 23 in batt)"

− - "Slightly oversized batt for tighter friction fit (per manufacturer's recommendation)"

−default: "Match stud spacing nominal width (16 in stud — 15 in batt; 24 in stud — 23 in batt)"

−```

−

−## Cutting and Fitting at Top and Bottom of Cavity {toc}

−

−### Folded batts at runners create local compression that reduces the effective cavity depth and provides poorer absorption than a flat-cut batt fitted snugly to the runner. {note}

−

−### Batts at the top and bottom of the cavity shall be cut to the cavity length and fitted without fold-over or compression.

−

−### The Contractor shall use a sharp utility knife or insulation knife to cut batts cleanly, because tearing batts produces a ragged edge that does not seat well against framing.

−

−## Around Doors, Windows, and Other Openings {toc}

−

−### Door and window openings are common sources of acoustic flanking, and any cavity space adjacent to such openings that is left uninsulated short-circuits the acoustic performance of the surrounding partition. {note}

−

−### Insulation shall extend into all cavity space adjacent to door and window rough openings, around blocking for grab bars or backing, and into furred-out spaces at columns and other irregular conditions.

−

−## Plenum Insulation {toc}

−

−### Where the project requires plenum acoustic treatment above suspended ceilings, batt insulation shall be laid over the ceiling tiles on both sides of the partition for a width of at least 4 feet on each side, or extended fully across the room as indicated on the drawings.

−

−### Insulation laid over tiles shall be sized so it bears on the suspension grid rather than on the tile face, because insulation bearing on the face of a thin tile produces visible sag that the Owner will reject.

−

−### Batts shall be cut around recessed light fixtures and other in-plenum equipment to maintain manufacturer-required clearances.

−

−### Plenum Batt Width {toc}

−

−```datasheet

−label: Plenum Batt — Width Each Side of Partition

−type: select

−unit: ft

−options:

− - "4 ft each side (standard)"

− - "6 ft each side"

− - "Full ceiling area"

−drawing_ref: "plenum acoustic treatment plan"

−default: "4 ft each side (standard)"

−```

−

−## Floor and Ceiling Cavity Insulation {toc}

−

−### The IIC and STC performance of a floor/ceiling assembly is similarly sensitive to cavity-fill completeness. {note}

−

−### In wood- or steel-joisted floor/ceiling cavities, batts shall be installed friction-fit between joists and retained by wire support rods, plastic mesh, or strapping at 18 inches on center to prevent sag.

−

−### The full joist depth shall be filled where the assembly is intended to provide acoustic separation between floors.

−

−### Mechanical equipment, recessed lighting, and other in-cavity items shall be split around with the same care as in stud cavities.

−

−# Continuity and Perimeter Treatment {toc}

−

−## Top of Partition {toc}

−

−### The top of the partition is among the most frequently compromised conditions in acoustic and fire-rated work. {note}

−

−### Where the partition extends deck-to-deck, the insulation shall fill the cavity continuously from the floor runner to the deck above, without leaving an unfilled space at the head-of-wall joint.

−

−### Where the partition includes a deflection head detail, the insulation shall be cut to allow the slip track movement while still fully filling the cavity below the deflection range, or a compressible insulation shall be used at the head joint as specified by the tested assembly.

−

−### Where the partition terminates at the suspended ceiling, the cavity above the ceiling line shall be insulated, plenum-barriered, or both, as specified by the drawings.

−

−### A partition that terminates at the ceiling without plenum treatment provides only the limited acoustic separation that the suspended ceiling alone provides, typically much lower than the partition's nominal STC. {note}

−

−## Penetrations and Firestopping {toc}

−

−### Cavity-fill insulation, even fully installed, does not provide the rated stopping performance required at a penetration; the firestopping system is required in addition to the cavity insulation. {note}

−

−### Acoustic insulation is not a substitute for firestopping at penetrations through rated assemblies.

−

−### Penetrations — for conduit, piping, ductwork, cable trays, and other building services — shall be firestopped in accordance with [[sync/firestopping]] and with the rated penetration designs cited on the drawings.

−

−### ASTM C919 acoustic sealant shall be applied around all penetrations and at all perimeter conditions of acoustically rated partitions, coordinated with [[sync/gypsum-board-assemblies]].

−

−## Acoustic Sealant Coordination {toc}

−

−### Acoustic insulation in the cavity provides no STC benefit if perimeter air paths around the gypsum board face leak sound around the assembly. {note}

−### Cavity-fill insulation and perimeter acoustic sealant are mutually dependent; either alone is insufficient. {note}

−

−### The Contractor shall coordinate insulation installation with the application of acoustic sealant at floor runners, top runners, perimeter conditions at adjacent walls and columns, and at all penetrations.

−

−# Coordination with Penetrations and Firestopping {toc}

−

−## Back-to-back electrical boxes are an acoustic flanking path that no amount of cavity insulation will mitigate. {note}

−

−## Where rated assemblies contain penetrations — for conduit, sleeves, pipe, ductwork, electrical boxes, and cable trays — the firestopping system at each penetration shall be selected from the applicable UL or GA-listed penetration firestop designs for the assembly.

−

−## Acoustic cavity-fill insulation shall be installed continuously up to and around the penetration, with care taken to avoid disturbing the firestop assembly.

−

−## The firestopping installer shall coordinate timing with the insulation installer; where firestop must be re-applied after cavity insulation is in place, the insulation shall be reinstated to its installed condition before the cavity is closed.

−

−## The gypsum-board specification (see [[sync/gypsum-board-assemblies]]) shall be enforced to require offset of back-to-back boxes by 24 inches minimum and the use of acoustic putty pads or listed acoustic box covers in high-STC partitions.

−

−# Mock-Ups {toc}

−

−## Where field testing is also specified, the mock-up may serve as the test specimen for field STC verification per ASTM E336 before production partition work proceeds, allowing any deficiencies to be corrected at a single representative location rather than across the entire project.

−

−## Where the project includes high-STC rated assemblies (STC 55 or higher), critical-listening rooms, or other acoustically demanding spaces, a mock-up of each rated partition type may be required by the contract documents.

−

−## The mock-up shall include the framing, cavity insulation as specified, both face layers of gypsum board, all accessories, and perimeter sealing, so that the complete assembly can be reviewed by the Architect and the acoustic consultant before production work begins.

−

−## Mock-Up Requirement {toc}

−

−```datasheet

−label: Mock-Up Required

−type: radio

−options:

− - "Yes — one mock-up per high-STC partition type (STC 55+)"

− - "Yes — one mock-up of each rated partition type"

− - "No"

−default: "No"

−```

−

−# Field Testing {toc}

−

−## STC Field Verification {toc}

−

−### Field acoustic testing per ASTM E336 measures the apparent sound transmission class (ASTC) or the noise isolation class (NIC) of an installed partition or assembly, accounting for flanking paths and construction variations that laboratory tests do not capture. {note}

−### Field-tested values typically run 3 to 5 STC points below the laboratory rating of the same assembly. {note}

−

−### Where field testing is specified, the acceptance criterion shall be expressed as a minimum field-measured ASTC or NIC, not as the laboratory STC value, because requiring the laboratory STC in the field is generally unachievable and creates dispute conditions.

−

−### Field Acoustic Testing and Acceptance {toc}

−

−```datasheet

−label: Field Acoustic Testing Required

−type: radio

−options:

− - "Yes — ASTM E336 measurement by independent accredited testing agency"

− - "Yes — owner-furnished testing"

− - "No"

−drawing_ref: true

−default: "No"

−```

−

−```datasheet

−label: Field Acoustic Acceptance Criterion

−type: select

−options:

− - "ASTC ≥ STC – 5 (typical specification)"

− - "ASTC ≥ STC – 3 (tight specification, high-performance work)"

− - "NIC ≥ specified noise isolation class"

−drawing_ref: "acoustic acceptance criteria schedule"

−default: "ASTC ≥ STC – 5 (typical specification)"

−```

−

−## Testing Conditions {toc}

−

−### Field testing shall be performed by an independent accredited acoustic testing agency with experience in commercial construction field measurements.

−

−### Tests shall be conducted after all penetrations, perimeter sealing, doors, and adjacent finishes are complete; testing before finishes are complete will produce results that do not reflect final assembly performance and shall not be used as the basis for acceptance.

−

−### The testing agency shall provide a test report for each tested assembly including the source and receive room volumes, the measurement method (ASTM E336 procedure), the third-octave-band transmission loss data, the calculated ASTC or NIC, the acceptance criterion, the pass/fail determination, and any corrective action recommended for failed assemblies.

−

−## Corrective Action for Failed Tests {toc}

−

−### The most common causes of a failed field test are incomplete cavity fill, perimeter leakage, back-to-back electrical boxes, or door-frame leakage. {note}

−

−### Where a field-tested partition does not meet the acceptance criterion, the Contractor shall investigate the cause and shall implement corrective measures before re-test.

−

−### The Contractor shall not adjust the acceptance criterion or argue that the laboratory STC is satisfied by an inferior field measurement; the contract specifies the field performance and the field performance shall be achieved.

−

−# Delivery, Storage, and Handling {toc}

−

−## Acoustic insulation shall be delivered to the project in the manufacturer's original packaging with all labels and markings intact.

−

−## Bundles shall be stored indoors in a dry, climate-controlled location, off the ground on pallets or sleepers, and protected from rain, condensation, mechanical damage, and direct sun.

−

−## Plastic shipping wrap shall remain on bundles until they are brought to the point of installation; opened bundles shall be installed promptly or returned to enclosed storage.

−

−## Bundles that have been wetted shall be inspected.

−

−## Mineral wool products that have been briefly wetted may be dried and used if no fiber-matrix deformation is evident, but bundles showing crushing, compression set, or mold growth shall be rejected.

−

−## Glass fiber products that have been wetted shall be rejected, because the binder softens and the batt loses dimensional stability.

−

−## Insulation shall not be exposed to direct UV for prolonged periods, because the binder in some glass fiber products is UV-sensitive.

−

−## Temporary storage outdoors under tarp is acceptable only for short durations and only with full protection from precipitation; long-term outdoor storage shall not be used.

−

−# Warranty {toc}

−

−## Manufacturer's Warranty {toc}

−

−### Acoustic insulation products shall be warranted by the manufacturer against defects in materials and workmanship for a minimum period of one year from the date of delivery.

−

−### Mineral wool board products and engineered acoustic batts carrying extended manufacturer warranties shall be warranted for the period stated by the manufacturer.

−

−## Installer's Warranty {toc}

−

−### Workmanship defects include, but are not limited to, missing cavity fill, sagged or settled batts, compressed batts in undersized cavities, and unfilled spaces around blocking, boxes, or penetrations that compromise the rated performance of the assembly. {note}

−

−### The Contractor shall warrant the acoustic insulation installation — including cavity fill completeness, retention, and integration with the host assembly — against defective workmanship for the project warranty period.

−

−### Installation Warranty Period {toc}

−

−```datasheet

−label: Installation Warranty Period

−type: select

−options:

− - "1 year from substantial completion"

− - "2 years from substantial completion"

−default: "1 year from substantial completion"

−```

−

−## Conditions Voiding Warranty {toc}

−

−### The warranty is voided by subsequent water intrusion, modifications by others that disturb the cavity insulation, and removal or alteration of insulation during post-occupancy work that is not restored to the installed condition.

−

−### The Contractor shall document any conditions observed during installation that may affect the long-term performance of the insulation — evidence of water infiltration, inadequate climate control, or trades disturbing previously installed cavity insulation — and shall bring them to the Architect's attention before the cavity is closed.

+---

+title: Acoustic Insulation

+category: Architectural

+description: >

+ When to use: Sound-attenuation cavity fill installed in the concealed cavities of interior partitions, in floor-ceiling assemblies, and above suspended ceilings as plenum attenuation, where the purpose of the fill is to raise the airborne sound transmission loss of the host assembly. Covers mineral wool, glass fiber, polyester fiber, and cotton fiber batts, blankets, and boards in that service; the tested-assembly basis that governs what goes in each partition type; fiber family, facing, surface burning, and noncombustibility as project-wide policy; minimum density and fill thickness; retention in vertical and horizontal cavities; plenum attenuation blankets and plenum barriers; installation, inspection before concealment, mock-ups, and field acoustic testing.

+ Not intended for: Thermal insulation in the building envelope and the vapor retarder, air barrier, and energy code obligations that go with it (see [[sync/building-thermal-insulation]]); the gypsum board partition itself, its framing, resilient channels, perimeter acoustic sealant, and electrical box treatment (see [[sync/gypsum-board-assemblies]]); duct liner and duct wrap (see [[sync/hvac-ductwork]]); pipe and equipment insulation (see [[sync/mechanical-insulation]]); firestopping of penetrations and head-of-wall joints in rated assemblies (see [[sync/firestopping]]); the ceiling attenuation class of a suspended ceiling system (see [[sync/suspended-acoustical-ceilings]]); exposed sound-absorbing finishes (see [[sync/acoustic-wall-panels]] and [[sync/acoustic-ceiling-clouds-and-baffles]]); acoustic door seals and gasketing (see [[sync/doors-frames-and-hardware]]); underlayments and resilient layers that raise the impact insulation class of a floor; vibration isolation of equipment; and electronic sound masking.

+---

+# Scope {toc}

+## This standard governs the selection, fire and smoke properties, density, thickness, retention, installation, and verification of sound-attenuation insulation placed inside interior partition cavities, inside floor-ceiling assemblies, and above suspended ceilings for the purpose of reducing airborne sound transmission between spaces. {note}

+## The fill covered here is one component of a tested assembly. The sound transmission class of a partition or a floor-ceiling assembly is a property of the whole system, in which the board layers, the framing and its spacing, the cavity depth, the decoupling accessories, the perimeter seal, and the cavity fill each contribute, and the tested assembly that a project cites fixes all of them together. {note}

+## Cavity fill raises transmission loss by damping the air in the cavity rather than by adding mass. Air oscillating through a porous fiber matrix loses energy to friction, which suppresses the mass-air-mass resonance of a double-leaf partition and absorbs the standing waves that would otherwise couple the two faces through the cavity. {note}

+## Because the fill works by airflow resistance and not by weight, its contribution rises steeply from an empty cavity to a lightly filled one and then flattens; beyond the density at which the flow resistance of the fill exceeds what the cavity needs, added density buys stiffness and fire performance rather than sound transmission class. {note}

+## The following are governed elsewhere and are outside this standard: {note}

+- the gypsum board partition, its framing, resilient channels, multi-layer board schedules, perimeter acoustic sealant, and the offset and treatment of electrical boxes, which are governed by [[sync/gypsum-board-assemblies]]

+- thermal insulation in the building envelope, including any vapor retarder the envelope needs, which is governed by [[sync/building-thermal-insulation]]

+- firestopping of penetrations and of the head-of-wall joint in fire-resistance-rated assemblies, which is governed by [[sync/firestopping]]

+- the ceiling attenuation class of a suspended ceiling system, which is governed by [[sync/suspended-acoustical-ceilings]]

+- exposed sound-absorbing wall and ceiling finishes, which are governed by [[sync/acoustic-wall-panels]] and [[sync/acoustic-ceiling-clouds-and-baffles]]

+- acoustic seals at door and frame perimeters, which are governed by [[sync/doors-frames-and-hardware]]

+- duct liner, duct wrap, and pipe insulation, which are governed by [[sync/hvac-ductwork]] and [[sync/mechanical-insulation]]

+- the wood or cold-formed steel framing that forms the cavities, which is governed by [[sync/wood-framing]] and [[sync/cold-formed-metal-framing]]

+## The partition types that receive acoustic cavity fill shall be as indicated on [[drawing: the partition schedule]].

+## The floor-ceiling assemblies that receive acoustic cavity fill shall be as indicated on [[drawing: the floor and ceiling assembly schedule]].

+## Where one product serves both the acoustic function under this standard and the thermal function of the building envelope, the thermal resistance, vapor retarder, and air barrier requirements of [[sync/building-thermal-insulation]] shall govern the product, and this standard shall govern its acoustic density, thickness, fit, and retention.

+## The Contractor shall coordinate the cavity fill with the partition work under [[sync/gypsum-board-assemblies]], so that the fill, the framing, the board layers, and the perimeter seal are the components the cited tested assembly requires.

+# Referenced Standards {toc}

+## Materials, testing, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited in the Contract Documents.

+## Where the contract documents, the adopted building code, or a referenced standard impose conflicting requirements, the more stringent requirement shall govern unless the Architect of Record directs otherwise in writing.

+| Standard | Title |

+|----------|-------|

+| ASTM C665 | Mineral-Fiber Blanket Thermal Insulation for Light Frame Construction and Manufactured Housing |

+| ASTM C553 | Mineral Fiber Blanket Thermal Insulation for Commercial and Industrial Applications |

+| ASTM C612 | Mineral Fiber Block and Board Thermal Insulation |

+| ASTM C1320 | Installation of Mineral Fiber Batt and Blanket Thermal Insulation for Light Frame Construction |

+| ASTM C522 | Airflow Resistance of Acoustical Materials |

+| ASTM C518 | Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus |

+| ASTM C1338 | Determining Fungi Resistance of Insulation Materials and Facings |

+| ASTM E84 | Surface Burning Characteristics of Building Materials |

+| UL 723 | Surface Burning Characteristics of Building Materials |

+| ASTM E136 | Behavior of Materials in a Vertical Tube Furnace at 750°C |

+| ASTM E119 | Fire Tests of Building Construction and Materials |

+| UL 263 | Fire Tests of Building Construction and Materials |

+| ASTM E90 | Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements |

+| ASTM E413 | Classification for Rating Sound Insulation |

+| ASTM E336 | Measurement of Airborne Sound Attenuation Between Rooms in Buildings |

+| ASTM E1414 | Airborne Sound Attenuation Between Rooms Sharing a Common Ceiling Plenum |

+| ASTM E492 | Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine |

+| ASTM E989 | Classification for Determination of Impact Insulation Class |

+| ASTM E1007 | Field Measurement of Tapping-Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures |

+| ASTM E96 | Water Vapor Transmission of Materials |

+| GA-600 | Fire Resistance and Sound Control Design Manual |

+| UL Fire Resistance Directory | Fire-Resistance-Rated Systems and Products |

+| ICC IBC | International Building Code |

+| ICC IMC | International Mechanical Code |

+| NFPA 90A | Installation of Air-Conditioning and Ventilating Systems |

+# Submittals {toc}

+## Action Submittals {toc}

+### The Contractor shall submit the following for review before acoustic insulation is procured:

+- product data for each product, stating the fiber family, the product form, the product standard and type designation, the nominal density, the thicknesses and widths furnished, the facing if any, and the airflow resistance per ASTM C522 where the manufacturer publishes it

+- surface burning test reports per ASTM E84 or UL 723 for each product, and for the faced product as installed where a facing is furnished

+- noncombustibility test reports per ASTM E136 for each product required to be noncombustible

+- fungi resistance test reports per ASTM C1338 where the datasheet requires them

+- a schedule listing every partition type and floor-ceiling assembly that receives fill, the tested assembly cited for it, and the product, density, and thickness proposed for it

+- laboratory test reports per ASTM E90, ASTM E492, or ASTM E1414 supporting each cited tested assembly that is not a published design

+- manufacturer's installation instructions, including the batt widths designated for each framing spacing and framing material, and the published limits on cavity height without supplemental retention

+- product data for retention devices, support wires, netting, impaling pins, and adhesives

+- a sample of each product, not less than 12 in. by 12 in., in the thickness and density proposed

+```datasheet

+label: Action Submittals Required

+type: checkbox

+options:

+ - "Product data for each acoustic insulation product"

+ - "Surface burning test reports per ASTM E84 or UL 723"

+ - "Noncombustibility test reports per ASTM E136"

+ - "Fungi resistance test reports per ASTM C1338"

+ - "Schedule of assemblies, tested assembly citations, and proposed products"

+ - "Laboratory acoustic test reports supporting cited assemblies"

+ - "Manufacturer's installation instructions"

+ - "Retention device and adhesive product data"

+ - "Product samples"

+default:

+ - "Product data for each acoustic insulation product"

+ - "Surface burning test reports per ASTM E84 or UL 723"

+ - "Schedule of assemblies, tested assembly citations, and proposed products"

+ - "Manufacturer's installation instructions"

+```

+### Acoustic insulation shall not be installed in any assembly until the submittals covering the products in that assembly have been reviewed and returned.

+### The Contractor shall submit a written request before procuring any product that differs in fiber family, density, thickness, or facing from the reviewed submittal, and the request shall identify each tested assembly the change affects.

+## Closeout Submittals {toc}

+### The Contractor shall submit the following before the assemblies containing acoustic insulation are accepted:

+- a signed certificate stating that the installed insulation conforms to the reviewed submittals, the cited tested assemblies, the manufacturer's published instructions, and this standard

+- inspection records for each area inspected before concealment, identifying the date, the inspecting party, the assemblies inspected, and the disposition of any deficiency

+- field acoustic test reports where field testing is required

+- mock-up review records where mock-ups are required

+- manufacturer warranty documents for each product that carries a written material warranty

+```datasheet

+label: Closeout Submittals Required

+type: checkbox

+options:

+ - "Signed certificate of conformance"

+ - "Inspection records before concealment"

+ - "Field acoustic test reports"

+ - "Mock-up review records"

+ - "Manufacturer warranty documents"

+default:

+ - "Signed certificate of conformance"

+ - "Inspection records before concealment"

+```

+# Quality Assurance {toc}

+## Installer Qualifications {toc}

+### Acoustic insulation shall be installed by personnel experienced in cavity insulation for commercial partition and floor-ceiling construction.

+### The installing foreman shall have installed cavity fill in acoustically rated or fire-resistance-rated assemblies on not fewer than three completed projects.

+### Cavity fill is concealed within days of installation and its shortcomings surface months later as a room that fails a field test or a tenant complaint, so the skill that matters is the discipline of splitting, fitting, and filling around every obstruction rather than any special tooling. {note}

+## Preinstallation Coordination {toc}

+### Before the first cavity is filled, the Contractor shall confirm against the reviewed schedule that the product, density, and thickness on hand for each partition type and floor-ceiling assembly match the tested assembly cited for it.

+### The Contractor shall coordinate the sequence of cavity fill with the framing, electrical, plumbing, fire protection, and low-voltage trades so that in-cavity rough-in is complete before the fill is placed.

+### Where a trade must reopen a filled cavity, the Contractor shall reinstate the fill to its inspected condition before the cavity is closed.

+## Inspection Before Concealment {toc}

+### The assemblies whose cavity fill is inspected before the closing face is applied shall be as indicated in the datasheet.

+```datasheet

+label: Cavity Fill Inspection Before Concealment

+type: select

+options:

+ - "Every cavity that receives fill"

+ - "Fire-resistance-rated and acoustically rated assemblies"

+ - "Fire-resistance-rated assemblies"

+ - "A representative sample of each partition type"

+ - "None beyond the inspections the adopted code requires"

+default: "Fire-resistance-rated and acoustically rated assemblies"

+```

+### The Contractor shall give the inspecting party not less than two working days' notice before the closing face of an assembly selected for inspection is applied.

+### The Contractor shall not apply the closing face of an assembly selected for inspection until the fill has been inspected and released, or until the inspecting party has waived the inspection in writing.

+### Where the parties disagree whether a cavity is completely filled, the Architect of Record shall make the initial determination.

+### A cavity that is closed without a required inspection shall be reopened at the Contractor's expense to the extent the inspecting party requires to verify the fill.

+## Product Labeling {toc}

+### Each product shall be labeled by the manufacturer with the product name, the fiber family, the product standard and type designation, the nominal density, the thickness, and the surface burning classification.

+### Labels shall remain on delivered bundles until the bundle is opened at its point of installation.

+### Insulation that cannot be identified to a reviewed submittal shall be removed from the site.

+## Fungi Resistance {toc}

+### Mineral fiber and glass fiber are inorganic and do not themselves feed fungal growth, but dust, organic debris, and the organic binder on the fiber surface can support growth where the fill stays wet, so a dry cavity is the primary defense and the test evidence is a secondary one. {note}

+### The evidence of fungi resistance furnished for each product shall be as indicated in the datasheet.

+```datasheet

+label: Fungi Resistance Evidence

+type: radio

+options:

+ - "ASTM C1338 test report showing no growth"

+ - "Manufacturer's written statement of inorganic composition"

+ - "Not required"

+```

+# Environmental and Service Conditions {toc}

+## Acoustic cavity fill under this standard is intended for dry, conditioned interior cavities and plenums, and the products it covers are not selected for repeated wetting, condensation, or freeze-thaw exposure. {note}

+## Insulation shall not be installed against a wet substrate or in a cavity with an active water source until the source is corrected and the substrate is dry.

+## Insulation that has become saturated shall be removed and replaced rather than dried in place.

+## A batt that has been saturated rarely returns to its installed thickness, and residual moisture in the fiber matrix supports growth on the surface, so drying in place trades a visible defect for a concealed one. {note}

+## Fill in contact with a recessed luminaire, a flue, a chimney, or another heat-producing item shall be held clear of it by the distance the item's listing requires.

+## Where an interior partition is also part of the building envelope, the vapor retarder and air barrier of that assembly shall be provided under [[sync/building-thermal-insulation]] rather than by the acoustic fill or its facing.

+# Tested Assembly Basis {toc}

+## Sound-rated and fire-rated assemblies are built to a tested design, and the cavity fill is one of the components the design fixes. The fill named in a tested assembly is not a suggestion: a lighter density, a thinner batt, a different fiber family, or a facing the test did not include changes the assembly into one that was not tested. {note}

+## The tested assembly governing each partition type that receives cavity fill shall be as indicated on [[drawing: the partition schedule]].

+## The sound transmission class required of each partition type shall be as indicated on [[drawing: the partition schedule]].

+## The tested assembly governing each floor-ceiling assembly that receives cavity fill shall be as indicated on [[drawing: the floor and ceiling assembly schedule]].

+## The fire-resistance design governing each rated assembly that receives cavity fill shall be as indicated on [[drawing: the partition and floor-ceiling assembly schedules]].

+## The sources of tested assembly data accepted on the project shall be as indicated in the datasheet.

+```datasheet

+label: Accepted Sources of Tested Assembly Data

+type: checkbox

+options:

+ - "GA-600 sound-rated designs"

+ - "UL fire-resistance designs carrying published acoustic ratings"

+ - "ASTM E90 or ASTM E492 reports from an independent accredited laboratory"

+ - "Manufacturer-sponsored ASTM E90 or ASTM E492 reports from an accredited laboratory"

+ - "Published research-institute test catalogs"

+default:

+ - "GA-600 sound-rated designs"

+ - "UL fire-resistance designs carrying published acoustic ratings"

+ - "ASTM E90 or ASTM E492 reports from an independent accredited laboratory"

+```

+## Where a cited fire-resistance design lists the cavity insulation as optional, the fill shall be installed to the density and thickness the acoustic assembly requires, and the fire-resistance design shall be confirmed to permit that fill in that thickness before the cavity is closed.

+## Many fire-resistance designs list batts as optional, some limit their thickness or fiber family, and a few were tested without any fill, because insulation that holds heat against the fire-side board can shorten the time to failure; the acoustic requirement and the fire requirement therefore have to be checked against the same design rather than assumed compatible. {note}

+## The Contractor shall not substitute a product of a different fiber family, lesser density, lesser thickness, or different facing for the one a cited tested assembly names without the Architect of Record's written acceptance.

+## Where the schedule cites no tested assembly for a partition type that receives fill, the fill shall be the material, minimum density, and thickness recorded in the datasheet for partitions.

+# Cavity Fill Material {toc}

+## Fiber Family by Application {toc}

+### The fiber family and product form used in partition cavities shall be as indicated in the datasheet.

+```datasheet

+label: Partition Cavity Fill Material

+type: select

+options:

+ - "Stone wool batt"

+ - "Slag wool batt"

+ - "Mineral wool batt, stone or slag"

+ - "Glass fiber batt"

+ - "Mineral wool board"

+ - "Glass fiber board"

+ - "Polyester fiber batt"

+ - "Cotton fiber batt"

+```

+### The fiber family and product form used in floor-ceiling cavities shall be as indicated in the datasheet.

+```datasheet

+label: Floor-Ceiling Cavity Fill Material

+type: select

+options:

+ - "Stone wool batt"

+ - "Slag wool batt"

+ - "Mineral wool batt, stone or slag"

+ - "Glass fiber batt"

+ - "Mineral wool board"

+ - "Glass fiber board"

+ - "Polyester fiber batt"

+ - "Cotton fiber batt"

+```

+### No fiber family is the norm across projects, so neither field asserts a default: the choice turns on whether the cited assemblies name a family, whether noncombustibility is required, the cavity heights involved, and the cost the project bears for the stiffer product. {note}

+### Stone wool is spun from molten basalt or similar rock, slag wool from molten blast furnace slag, and the two are sold together in the United States under the mineral wool designation with the same product standards, the same density range, and closely similar acoustic performance; a fire-resistance design that names mineral wool is satisfied by either. {note}

+### Where a cited assembly names stone wool specifically, or the datasheet records stone wool, slag wool shall not be substituted for it.

+### Mineral wool holds its dimensions at the temperatures reached in a fire test and is stiff enough to stand in a tall cavity without support, which is why fire-resistance designs that require fill usually name it and why it is the family used where a partition cavity is taller than the height at which glass fiber batts sag. {note}

+### Glass fiber batts of the density sold for sound attenuation have airflow resistance in the range that damps a stud cavity, so at equal thickness their contribution to sound transmission class is close to that of mineral wool, and at equal thickness they generally cost less and weigh less; the difference between the families shows up in stiffness, temperature performance, and noncombustibility rather than in transmission loss. {note}

+### Polyester fiber and cotton fiber batts are organic products that reach the surface burning limits of this standard through a treatment rather than through the fiber, and they do not qualify as noncombustible; where the datasheet records either, the surface burning test report shall cover the product in the density and thickness supplied. {note}

+### Where the datasheet records a polyester fiber or cotton fiber product, it shall not be installed in an assembly whose cited tested assembly names mineral fiber, and it shall not be installed where the datasheet requires noncombustibility.

+## Product Standards by Form {toc}

+### Mineral wool and glass fiber batts for light-frame cavities shall conform to ASTM C665.

+### Mineral wool and glass fiber blankets for commercial and industrial cavities and for plenum attenuation shall conform to ASTM C553.

+### Mineral wool and glass fiber board shall conform to ASTM C612.

+### An ASTM C665 batt is classified by facing, an ASTM C553 blanket by service temperature and density, and an ASTM C612 board by density and temperature limit, so the type designation the submittal cites is settled by the form and density selected rather than by a separate decision. {note}

+### Polyester fiber and cotton fiber batts shall be furnished with third-party test reports for thermal resistance per ASTM C518, surface burning per ASTM E84 or UL 723, and fungi resistance per ASTM C1338 in the density and thickness supplied.

+## Noncombustibility {toc}

+### Whether the cavity fill is required to be noncombustible per ASTM E136 shall be as indicated in the datasheet.

+```datasheet

+label: Noncombustibility per ASTM E136

+type: select

+derived: "the fire-resistance designs cited on the assembly schedules and the material limitations the adopted building code places on the building's type of construction"

+options:

+ - "Required for all cavity fill"

+ - "Required where the cited fire-resistance design names mineral wool or noncombustible fill"

+ - "Not required"

+default: derived

+```

+### Unfaced mineral wool and unfaced glass fiber pass ASTM E136 because the inorganic fiber and the small binder fraction stay below the test's mass loss and temperature rise limits; a kraft, foil, or scrim facing is a combustible layer that the faced product cannot carry through the test. {note}

+### The adopted building code permits combustible insulation, other than foam plastic, in buildings of noncombustible construction where the insulation's flame spread index does not exceed 25, so type of construction alone does not make noncombustibility mandatory; the fire-resistance design cited for the assembly is what usually does. {note}

+### Where noncombustibility is required, a faced product, a polyester fiber product, or a cotton fiber product shall not be installed in that assembly.

+## Surface Burning {toc}

+### Surface burning characteristics shall be determined per ASTM E84 or UL 723 on the product in the thickness and density supplied.

+### The surface burning limits the cavity fill shall meet shall be as indicated in the datasheet.

+```datasheet

+label: Surface Burning Limits for Cavity Fill

+type: radio

+options:

+ - "Flame spread index 25 or less and smoke-developed index 50 or less"

+ - "Flame spread index 25 or less and smoke-developed index 450 or less"

+default: "Flame spread index 25 or less and smoke-developed index 50 or less"

+```

+### The adopted building code sets a flame spread index of 25 and a smoke-developed index of 450 as the limit for insulation concealed in a building of any construction type, while insulation exposed within a plenum is held to a smoke-developed index of 50 under the adopted mechanical code and NFPA 90A; unfaced mineral fiber meets the plenum limit as manufactured, which is why the tighter limit is the one most projects record for all of the fill. {note}

+### Fill installed exposed within a plenum shall have a flame spread index of 25 or less and a smoke-developed index of 50 or less regardless of the datasheet selection.

+### Where a faced product is installed with its facing exposed within a plenum, the faced product as installed shall meet the plenum limit.

+## Facing {toc}

+### The facing on cavity fill shall be as indicated in the datasheet.

+```datasheet

+label: Insulation Facing

+type: radio

+options:

+ - "Unfaced"

+ - "Kraft-faced"

+ - "Foil-faced"

+ - "FSK-faced"

+default: "Unfaced"

+```

+### A facing on the cavity fill has a small effect on transmission loss, because the porous fill behind it still damps the cavity, but the facing is a combustible membrane, it is the component that fails the noncombustibility test, and it is a vapor retarder placed on whichever side of the cavity the batt happens to face; unfaced fill has none of these consequences, which is why it is the norm for the acoustic function. {note}

+### Where the datasheet records a faced product, the facing shall be placed on the side of the cavity that the vapor control design of the assembly requires, as coordinated under [[sync/building-thermal-insulation]].

+### Where the facing is intended to serve as the vapor retarder of the assembly, its permeance determined per ASTM E96 shall satisfy the vapor retarder class the adopted building code requires for [[parameter: climate-zone]].

+### A kraft or foil facing shall not be left exposed in an occupied space or in a concealed space in which the adopted building code requires the exposed surface to carry a surface burning classification the faced product does not hold.

+### Where the datasheet records a faced product and a cited tested assembly names unfaced fill, unfaced fill shall be installed in that assembly.

+# Density and Thickness {toc}

+## Minimum Density {toc}

+### The minimum nominal density of partition cavity fill shall be as indicated in the datasheet.

+```datasheet

+label: Partition Cavity Fill Minimum Nominal Density

+type: range

+unit: pcf

+options:

+ min: 0.5

+ max: 8

+ setpoints: [0.5, 0.7, 1, 1.5, 2, 2.5, 3, 4, 6, 8]

+```

+### The minimum nominal density of floor-ceiling cavity fill shall be as indicated in the datasheet.

+```datasheet

+label: Floor-Ceiling Cavity Fill Minimum Nominal Density

+type: range

+unit: pcf

+options:

+ min: 0.5

+ max: 8

+ setpoints: [0.5, 0.7, 1, 1.5, 2, 2.5, 3, 4, 6, 8]

+```

+### The density ladder spans both fiber families rather than one, so no value on it is the norm and neither field asserts a default. Glass fiber sound attenuation batts are sold between roughly 0.5 and 2.5 pcf, mineral wool batts between 2.5 and 4 pcf, and mineral wool board from 4 pcf up to 8 pcf; a minimum recorded at the low end of the ladder admits either family, and one recorded at 2.5 pcf or above effectively names mineral wool or the heavier glass fiber blankets. {note}

+### In a stud cavity, the contribution of the fill to sound transmission class levels off between roughly 2.5 and 3.5 pcf, and a 6 pcf board in the same cavity delivers close to the same rating as a 3 pcf batt; density above that plateau is bought for dimensional stability in tall cavities, for the fire-resistance design, or for a board product that has to stand on its own, not for transmission loss. {note}

+### Glass fiber batts below roughly 1.5 pcf sag in a vertical cavity taller than the height the manufacturer publishes for unsupported installation, and the void that opens at the top of the cavity costs more transmission loss than the lighter batt saved, so where a light-density product is recorded the retention provisions of this standard carry the weight of the acoustic result. {note}

+### Where a cited tested assembly names a density greater than the datasheet minimum, the density the assembly names shall be installed in that assembly.

+## Fill Thickness {toc}

+### The fill thickness for each partition type shall be as indicated in the datasheet.

+```datasheet

+label: Partition Cavity Fill Thickness

+type: range

+unit: in.

+drawing_ref: "the partition schedule"

+options:

+ min: 1

+ max: 8

+ setpoints: [1, 1.5, 2, 2.5, 3, 3.5, 4, 5.5, 6, 8]

+default: deferred

+```

+### The fill thickness for each floor-ceiling assembly shall be as indicated in the datasheet.

+```datasheet

+label: Floor-Ceiling Cavity Fill Thickness

+type: range

+unit: in.

+drawing_ref: "the floor and ceiling assembly schedule"

+options:

+ min: 1.5

+ max: 16

+ setpoints: [1.5, 2.5, 3.5, 5.5, 6, 8, 9.5, 10, 12, 14, 16]

+default: deferred

+```

+### Fill thickness follows the cavity of each assembly type, and a project with several stud depths and joist depths has several answers, which is why both thicknesses are recorded per assembly on the schedules rather than once for the project. {note}

+### Where the schedule states no fill thickness for a partition type that receives fill, the fill shall be the full depth of the cavity from runner to runner.

+### Where a cited tested assembly names a thickness less than the cavity depth, the thickness the assembly names shall be installed in that assembly unless the Architect of Record directs a greater thickness in writing.

+### A partly filled stud cavity leaves an air layer that still behaves as a spring between the two faces, so the transmission loss of a partial fill falls between an empty cavity and a full one; a partial fill in a floor-ceiling cavity is a different case, because the joist depth usually exceeds what the assembly needs and the tested assemblies for floors were commonly run with a batt thinner than the joist. {note}

+### Fill thicker than the cavity depth shall not be installed.

+### A batt compressed into a cavity shallower than its nominal thickness performs no better than a batt matched to the cavity, and the excess pushes the face board off the framing, opens the perimeter seal, and leaves the board fasteners without a flat bearing. {note}

+# Plenum Attenuation {toc}

+## Plenum Flanking {toc}

+### Where a partition stops at a suspended ceiling, sound crosses from one room to the next over the partition through the shared plenum, and the ceiling system on each side is the only barrier in that path; the rating of that path is the ceiling attenuation class measured per ASTM E1414, which belongs to the ceiling system and is governed by [[sync/suspended-acoustical-ceilings]]. {note}

+### A partition that stops at the ceiling delivers the transmission loss of the plenum path or of the partition, whichever is lower, so a high sound transmission class in the partition is wasted unless the plenum path is treated to a comparable level or the partition is carried to the structure. {note}

+### The partitions that receive plenum attenuation treatment shall be as indicated on [[drawing: the partition schedule]].

+## Plenum Treatment Selection {toc}

+### The plenum attenuation treatments employed on the project shall be as indicated in the datasheet.

+```datasheet

+label: Plenum Attenuation Treatments Employed

+type: checkbox

+options:

+ - "Blanket laid over the ceiling on each side of the partition"

+ - "Blanket laid over the full ceiling area of the rooms separated"

+ - "Mineral wool board plenum barrier from the partition head to the structure"

+ - "Composite plenum barrier with a limp-mass septum"

+ - "None"

+```

+### A blanket laid over the ceiling raises the attenuation of the plenum path by adding absorption above the tile, and it improves the path by a few points at a cost of nothing but material; a plenum barrier closes the path and can bring the plenum route up to the partition's own rating, at the cost of coordinating every duct, pipe, and cable tray that crosses it, each of which needs its own seal to keep the barrier from becoming a leak. {note}

+### The material of plenum attenuation blankets shall be as indicated in the datasheet.

+```datasheet

+label: Plenum Attenuation Blanket Material

+type: select

+options:

+ - "Stone wool blanket"

+ - "Slag wool blanket"

+ - "Mineral wool blanket, stone or slag"

+ - "Glass fiber blanket"

+ - "Polyester fiber blanket"

+```

+### The width of blanket laid on each side of the partition shall be as indicated in the datasheet.

+```datasheet

+label: Plenum Blanket Width Each Side of the Partition

+type: range

+unit: ft

+drawing_ref: "the partition type details"

+options:

+ min: 2

+ max: 12

+ setpoints: [2, 3, 4, 5, 6, 8, 10, 12]

+default: deferred

+```

+### The thickness of plenum attenuation blankets shall be as indicated in the datasheet.

+```datasheet

+label: Plenum Attenuation Blanket Thickness

+type: range

+unit: in.

+drawing_ref: "the partition type details"

+options:

+ min: 1.5

+ max: 6

+ setpoints: [1.5, 2, 2.5, 3, 3.5, 4, 5.5, 6]

+default: deferred

+```

+### Plenum blankets are exposed within the plenum and shall meet the plenum surface burning limit of this standard.

+## Plenum Blanket Placement {toc}

+### Blankets laid over a suspended ceiling shall be cut to the ceiling module and placed so that their weight bears on the suspension grid rather than on the face of the tile.

+### A blanket bearing on a thin lay-in tile bows the tile within weeks, and the sag it produces in the ceiling line is the defect the Owner sees first. {note}

+### Blankets shall be held clear of recessed luminaires, air devices, and other in-plenum equipment by the clearance each item's listing requires, and the gap shall be closed with a fitted piece rather than left open.

+### Blankets shall be butted tightly at every joint and shall not be stretched to cover an area larger than the blanket.

+### Where the ceiling suspension system carries a fire-resistance rating, blankets shall be installed only where the ceiling's fire-resistance design permits them.

+# Retention and Attachment {toc}

+## Partition Cavity Retention {toc}

+### Batts in vertical stud cavities shall be retained by friction between the stud faces, using batts of the width the manufacturer designates for the framing spacing and the framing material.

+### Batts for cold-formed steel studs are made wider than the batts for wood studs at the same spacing, because the steel stud flange and the wood stud face leave different clear widths; a wood-stud batt in a steel-stud cavity leaves a gap along one flange, which is a common cause of a partition that fails its field test. {note}

+### Field-cut batts shall be cut between 1/2 in. and 1 in. wider than the clear cavity width so that the batt bears against both framing faces.

+### A batt cut narrower than the cavity shall be replaced rather than wedged in place, and a batt cut more than 1 in. wider than the cavity shall be trimmed rather than buckled into the cavity.

+### Supplemental retention shall be provided in partition cavities taller than the height indicated in the datasheet.

+```datasheet

+label: Partition Height Above Which Supplemental Retention Is Required

+type: range

+unit: ft

+options:

+ min: 8

+ max: 30

+ setpoints: [8, 10, 12, 14, 16, 20, 24, 30]

+```

+### The method of supplemental retention in partition cavities shall be as indicated in the datasheet.

+```datasheet

+label: Supplemental Retention Method in Partition Cavities

+type: select

+options:

+ - "Support wires or straps across the cavity"

+ - "Impaling pins with retaining washers"

+ - "Insulation retention clips at the framing"

+ - "Adhesive to the face board"

+ - "Friction fit alone"

+```

+### The height at which a friction-fit batt begins to slip is a property of the product's stiffness and density rather than of the framing, so the manufacturer's published unsupported height for the product recorded in the datasheet is the number the threshold is checked against, and the retention field records the method used above it. {note}

+### Where the manufacturer's published unsupported height for the product installed is less than the datasheet threshold, the published height shall govern.

+### Supplemental retention shall not compress the fill below its nominal thickness and shall not penetrate the face board.

+## Floor-Ceiling Cavity Retention {toc}

+### Fill in floor-ceiling cavities shall be retained against sagging and displacement by the method indicated in the datasheet.

+```datasheet

+label: Floor-Ceiling Cavity Retention Method

+type: select

+options:

+ - "Wire insulation supports sprung between the joists"

+ - "Netting or mesh stapled to the joists"

+ - "Strapping across the joists"

+ - "Support on the ceiling membrane or resilient channel"

+ - "Friction fit alone"

+```

+### The spacing of supports in floor-ceiling cavities shall be as indicated in the datasheet.

+```datasheet

+label: Floor-Ceiling Support Spacing

+type: range

+unit: in.

+options:

+ min: 12

+ max: 48

+ setpoints: [12, 16, 18, 24, 32, 48]

+```

+### A batt that rests on the ceiling membrane loads a resilient channel and shorts it against the joist, so where the assembly relies on a resilient channel for its rating the fill shall be held up off the channel unless the cited tested assembly was run with the fill resting on it.

+### Supports shall hold the fill at the position within the cavity depth that the cited tested assembly shows, whether against the subfloor, against the ceiling, or suspended between.

+## Board Attachment {toc}

+### Where the datasheet records a board product, the board shall be attached by the method indicated in the datasheet.

+```datasheet

+label: Board Attachment Method

+type: select

+options:

+ - "Impaling pins with retaining washers"

+ - "Adhesive"

+ - "Friction fit between framing"

+ - "Wire ties through the framing"

+ - "Mechanical fasteners with washers"

+```

+### Impaling pins shall be long enough to pass through the board and engage the substrate, and the retaining washer shall hold the board against the substrate without crushing it.

+### Board attached to a masonry or concrete substrate behind furring shall be attached to the substrate rather than to the furring where the furring is a resilient member.

+# Installation {toc}

+## Sequence {toc}

+### Cavity fill shall be installed after all in-cavity rough-in, blocking, bracing, and fireblocking is complete and inspected, and before the closing face of the assembly is applied.

+### Batt and blanket installation in light-frame cavities shall follow ASTM C1320 except where this standard or the cited tested assembly is more stringent.

+### The Contractor shall schedule the fill so that no trade needs access to a filled cavity before it is closed.

+### Fill that is displaced, torn, or compressed by later work shall be reinstated before the cavity is closed.

+## Fit and Continuity {toc}

+### Fill shall be continuous from runner to runner and from framing face to framing face, without gaps, voids, folds, or compression.

+### Field surveys of partitions that fail their field test find incomplete fill more often than any other single cause, and the deficiency is almost always a batt folded behind an obstruction, a cavity left short at the top, or a narrow batt in a steel-stud cavity. {note}

+### Batts shall be cut to the cavity length with a knife and fitted flat against the runners without folding.

+### A batt folded over at the runner packs the fold to a fraction of its thickness and leaves the runner cavity on the other side of the fold empty, which is the same defect as a short batt with a compressed batt added to it. {note}

+### Batts shall be split to pass wires, pipes, conduit, blocking, and bracing so that full thickness is maintained on both sides of the obstruction.

+### Batts shall be cut to fit around electrical boxes and other in-cavity devices so that the fill bears against the box on every side and is not compressed behind it.

+### Fill shall extend into the cavity space beside door and window rough openings, behind blocking and backing, and into furred spaces at columns and other irregular conditions.

+### The cavity beside a door frame is the last cavity to be filled and the first to be missed, and because door-frame leakage already dominates the flanking of most rated rooms, an empty stud bay beside the frame adds a second path at the weakest point of the partition. {note}

+## Head of Partition {toc}

+### Where the partition extends to the structure, the fill shall extend to the underside of the structure without an unfilled space at the head.

+### Where the partition has a deflection head, the fill shall extend to the top of the fixed portion of the cavity, and the deflection space shall receive the compressible fill or the joint treatment the cited assembly requires.

+### Where the partition stops at a suspended ceiling, the fill shall extend to the top of the partition, and the plenum above shall be treated as recorded in this standard for that partition type.

+### Fill shall not be substituted for the head-of-wall joint system or for firestopping in a fire-resistance-rated assembly, which are governed by [[sync/firestopping]].

+## Coordination with Perimeter Seal and Penetrations {toc}

+### Cavity fill and the perimeter acoustic seal of the partition depend on each other, because fill damps the cavity and the seal closes the air paths around the faces, and a partition with either one alone tests well below its rating. {note}

+### The Contractor shall coordinate the timing of fill with the application of acoustic sealant at the runners, the perimeter, and the penetrations under [[sync/gypsum-board-assemblies]], so that the fill is in place before the closing face is sealed.

+### Fill shall be installed continuously up to each penetration and shall not disturb an installed firestop system.

+### Where a firestop system is installed after the fill, the Contractor shall reinstate the fill around the penetration before the cavity is closed.

+### Back-to-back electrical boxes in one stud bay pass sound through the partition regardless of the fill, and the box offset and the putty pads that close that path are governed by [[sync/gypsum-board-assemblies]]. {note}

+# Field Acoustic Testing {toc}

+## Testing Requirement {toc}

+### Field acoustic testing of completed assemblies shall be as indicated in the datasheet.

+```datasheet

+label: Field Acoustic Testing

+type: radio

+options:

+ - "Not required"

+ - "ASTM E336 testing by an independent agency retained by the Contractor"

+ - "ASTM E336 testing by an independent agency retained by the Owner"

+default: "Not required"

+```

+### The assemblies subject to field testing shall be as indicated in the datasheet.

+```datasheet

+label: Assemblies Subject to Field Testing

+type: checkbox

+options:

+ - "Each acoustically rated partition type"

+ - "Each partition type at or above the threshold sound transmission class"

+ - "Each acoustically rated partition type on each floor"

+ - "Each acoustically rated floor-ceiling assembly type"

+```

+### The laboratory sound transmission class at or above which a partition type is subject to field testing shall be as indicated in the datasheet.

+```datasheet

+label: Minimum Laboratory STC of Partition Types Subject to Field Testing

+type: range

+unit: STC

+options:

+ min: 40

+ max: 65

+ setpoints: [40, 45, 50, 55, 60, 65]

+```

+### Field testing verifies the whole assembly and its flanking paths, most of which are outside this standard, so the party that pays for the test and the party responsible for a failure are not always the same; the testing field records who retains the agency, and the corrective action article assigns the cost by cause. {note}

+## Field Ratings and Acceptance {toc}

+### The field ratings reported for tested assemblies shall be as indicated in the datasheet.

+```datasheet

+label: Field Ratings Reported

+type: checkbox

+options:

+ - "Apparent sound transmission class per ASTM E336"

+ - "Noise isolation class per ASTM E336"

+ - "Normalized noise isolation class per ASTM E336"

+ - "Apparent impact insulation class per ASTM E1007"

+default:

+ - "Apparent sound transmission class per ASTM E336"

+```

+### The permitted shortfall of the field rating below the laboratory rating of the cited assembly shall be as indicated in the datasheet.

+```datasheet

+label: Permitted Shortfall of the Field Rating Below the Laboratory Rating

+type: range

+unit: points

+options:

+ min: 0

+ max: 5

+ setpoints: [0, 1, 2, 3, 4, 5]

+default: 5

+```

+### A field measurement includes every flanking path the laboratory specimen did not have, so field ratings run several points below the laboratory rating of the same assembly; the adopted building code sets the minimum field rating for assemblies between dwelling and sleeping units five points below the laboratory minimum, and that allowance is the reason the default here is five. {note}

+### The acceptance criterion for each tested assembly shall be the laboratory rating of the cited assembly less the permitted shortfall, and the laboratory rating shall not itself be the field acceptance criterion.

+### Where a rating is required by the adopted building code, the field acceptance criterion shall not be less than the field rating the code requires.

+## Testing Conditions {toc}

+### Field tests shall be performed by an independent testing agency experienced in field measurement under ASTM E336 and, where impact tests are required, under ASTM E1007.

+### Tests shall be performed after the perimeter seal, the penetrations, the doors, and the adjacent finishes of the tested assembly are complete, and a test performed before that point shall not be the basis of acceptance.

+### The test report for each assembly shall record the source and receiving room volumes, the measurement procedure, the one-third-octave band data, the computed rating, the acceptance criterion, the result, and the corrective action recommended where the assembly failed.

+## Corrective Action {toc}

+### Where a tested assembly does not meet its acceptance criterion, the Contractor shall investigate the cause, correct it, and retest the assembly.

+### The most common causes of a failed field test are incomplete cavity fill, a broken perimeter seal, back-to-back or unsealed electrical boxes, an untreated plenum path, and door-frame leakage, and a diagnostic measurement that locates the path is usually cheaper than reopening the partition on a guess. {note}

+### The cost of investigation, correction, and retesting shall be borne by the Contractor where the cause lies in the work under this standard or under another standard in the Contractor's scope, and by the Owner where the cause lies in the design of the assembly or in a flanking path the contract documents did not address.

+### Where the parties disagree on the cause of a failed test, the Architect of Record shall make the initial determination.

+# Mock-Ups {toc}

+## The mock-up requirement for partition types shall be as indicated in the datasheet.

+```datasheet

+label: Mock-Up Requirement

+type: radio

+options:

+ - "Not required"

+ - "One mock-up of each acoustically rated partition type"

+ - "One mock-up of each partition type at or above the threshold sound transmission class"

+default: "Not required"

+```

+## The laboratory sound transmission class at or above which a partition type requires a mock-up shall be as indicated in the datasheet.

+```datasheet

+label: Minimum Laboratory STC of Partition Types Requiring a Mock-Up

+type: range

+unit: STC

+options:

+ min: 45

+ max: 65

+ setpoints: [45, 50, 55, 60, 65]

+```

+## A mock-up of a high-rating partition lets the fill, the perimeter seal, the box treatment, and the head condition be reviewed together at one location before the same details are repeated across a floor, and where field testing is also required a tested mock-up finds a systemic defect at one partition instead of at fifty. {note}

+## Each mock-up shall include the framing, the cavity fill, every board layer, the accessories, and the perimeter seal of the partition type it represents, built in a location and to a size the Architect of Record accepts.

+## The closing face of the mock-up shall not be applied until the fill has been reviewed.

+## Where field testing is required, the mock-up may be tested under this standard and, where it passes, may remain as part of the work.

+## A mock-up that does not represent the cited assembly or does not pass its review shall be corrected or rebuilt at the Contractor's expense before production partitions of that type are closed.

+# Delivery, Storage, and Handling {toc}

+## Insulation shall be delivered in the manufacturer's packaging with labels intact.

+## Bundles shall be stored indoors, off the floor, and protected from water, from crushing, and from sunlight.

+## Temporary storage outdoors shall be under cover on a raised platform, and bundles stored outdoors shall be brought under roof before the packaging is opened.

+## Mineral wool that has been wetted and shows no crushing, compression set, or growth may be dried and installed; mineral wool showing any of those conditions shall be rejected.

+## Glass fiber, polyester fiber, or cotton fiber batts that have been wetted shall be rejected.

+## Water softens the binder in a glass fiber batt and the batt does not recover its thickness on drying, while a mineral wool batt sheds water and holds its shape unless it was crushed while wet, which is why the two are treated differently on delivery. {note}

+## Bundles shall remain wrapped until they are brought to the point of installation, and a bundle opened at the end of a shift shall be returned to enclosed storage.

+## Compressed packaging shall be opened far enough ahead of installation for the batts to recover their nominal thickness.

+# Warranty {toc}

+## The Contractor shall warrant the acoustic insulation installation against defects in materials and workmanship, including incomplete fill, sagged or displaced fill, compressed fill, and unfilled space around obstructions, for the period indicated in the datasheet, measured from the date of substantial completion.

+```datasheet

+label: Installation Warranty Period

+type: range

+unit: years

+options:

+ min: 1

+ max: 5

+ setpoints: [1, 2, 3, 5]

+default: 1

+```

+## Where the contract documents state a longer warranty period than the datasheet, the longer period shall govern.

+## The Contractor's cost of a warranty correction shall include opening and closing the assembly, reinstating the fill, restoring any firestop system or perimeter seal disturbed, refinishing the face, and retesting where the assembly was field tested.

+## Work performed under this warranty shall itself be warranted for a full new term equal to the original period measured from the date the correction is completed, or for the remainder of the original period, whichever ends later.

+## The warranty shall not cover fill disturbed by others after acceptance, fill wetted by a water source that arose after acceptance, or fill removed during post-occupancy work and not reinstated.

+## Where the Contractor observes a condition during installation that will shorten the life of the fill, including water entry, an unconditioned interior, or another trade disturbing installed fill, the Contractor shall report it to the Architect of Record in writing before the affected cavity is closed.

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