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Acoustical Data - Impact Insulation Class (IIC)

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SEE ATTACHMENT BELOW FOR IIC TEST RESULTS

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Understanding Acoustical Terms


Building materials and furnishings can affect the acoustics of a building in three ways:
  • Sound Absorption: They can absorb sound, lowering background noise levels and reducing reverberation within a room.
  • Airborne Sound Transmission: They can serve as acoustical insulation and reduce transmission of airborne sounds, such as voices, between rooms.
  • Impact Sound Transmission: They can serve as impact sound insulation and reduce the transmission of impact sound, such as footsteps, from one room to another below or adjacent to it.
 Resilient flooring is acoustically significant only in the area of impact sound transmission. However, it is important to have some understanding of generally accepted acoustical terms when talking with architects, specifiers, designers, builders and developers.


Sound Absorption

The installation of resilient flooring will add virtually no sound absorption to a room. Sufficient sound absorption can only be supplied by other room finishes (walls and ceilings) and furnishings (drapes, furniture, etc.).

The Noise Reduction Coefficient (NRC) is the rating of sound striking the material that is absorbed rather than reflected away by the material. NRC's range from .00 (no absorption) to 1.00 (100% absorption). Resilient flooring has an NRC of approximately 0.03 to 0.05; carpet (1/8” pile) is 0.10 to .15. The NRC of commercial acoustical ceiling is usually well in excess of .50.

Airborne Sound Transmission

Resilient flooring and carpet cannot significantly influence the transmission of airborne sounds, such as voices, between rooms. The determining factor is the basic construction of the building in question.

The Sound Transmission Class (STC) is the rating of airborne sound transmission. The STC of a floor/ceiling (or wall) structure is a measure of the decibel difference between the airborne sound energy striking one side of the structure and the sound energy radiated into a receiving room on the other side. Typical floor/ceiling structure STC values range from 25 to 35 for lightweight single family residential construction to upwards of 50 to 60 for commercial construction.

Impact Sound Transmission

The choice of floor covering can have a significant effect on the amount of impact sound transmitted from a room above to a room below. As in the case of airborne sound transmission, the total floor/ceiling structure strongly influences the impact sound transmission, the floor covering is also important. This is because the impact sound is generated by a shoe or other object impacting directly on the floor covering. The floor surfacing material can help cushion the impact and therefore reduce its effect on the sound transmitted to not only the rooms below, but also through the structural floor to adjacent rooms on the same floor.

The impact sound insulation properties of a floor/ceiling structure (including the flooring) are usually tested by measuring the transmitted sound in a room below while a standard "hammer machine" bangs on the floor above. The results of the test are rated in terms of the Impact Insulation Class (IIC). IIC values can range from as low as 25 for lightweight residential construction with no floor covering to over 65 for commercial construction with carpet. More typical values fall between 35 and 55. For multi-family structures, some codes require an IIC of 50 or more when tested in the laboratory (or 45 or more when tested in the field). Resilient flooring containing a foamed layer yields a higher (better) IIC rating than one without it.

IIC Values and Our Floors

Recently, we have received inquiries from builders and architects about impact noise ratings of resilient flooring over suspended concrete slabs and over lightweight concrete-capped wooden subfloors in multi-story residential buildings. Complaints of sound being transmitted from kitchens and bathrooms to spaces below in high-priced apartments and condominiums are increasing.

The following conclusions are drawn from laboratory testing over lightweight structures and from tests with a 6" thick concrete slab structural floor.
  1. Most resilient flooring that does not incorporate a cushioning structure and/or a felt backing will not significantly contribute to meeting or exceeding the requirements of an IIC 45 or 50 rating.
  2. Minor styling or structural differences have no significant effect on flooring IIC ratings.
  3. No currently available Armstrong commercial vinyl floor meets or exceeds an IIC requirement of 45 when tested on a standard 6" thick concrete floor/ceiling system.
  4. Among current Armstrong products installed with normal methods (no special underlayments), residential flooring with a foam interlayer, laminates with a foam underlayment or acoustical fabric, and linoleum consistently yields superior IIC rating performance (IIC 50 or greater) on concrete-capped wooden floors.
Typical Ranges of Resilient Flooring Laboratory IIC
Acoustical Ratings on Common Floor/Ceiling Constructions
 
Resilient Floor Covering
Category Or Other Floor Covering
Approximate IIC Rating on 6" Thick Concrete  Slab Floor (150 lbs/cu ft)Approximate IIC Rating On Lightweight Concrete-Capped Wood Floor
None (bare)2943 to 47
Vinyl with no backing or cushion
Vinyl Composition Tile
BioBased Tile
Medintone
Medley
Medintech
Royal
Natural Creations
Parallel
Natural Living
Natural Personality

LUXE
Luxe with FasTak
Natural Creations with I-Set
Alterna
Vivero Good 
Vivero Better
Vivero Best
Less than 45

 
45 to 49

 
Vinyl with backing
Rejuvenations
Connection Corlon
Possibilities Petit Point
Vivero Good LockingIIC:49 (w Drop Ceiling)
STC: 62 (w Drop Ceiling)
NA
Rotovinyls
Initiator
Less than 4545 to 52
Rotovinyls
Abode
Duality Premium w/ D10
4550
Rotovinyls
CushionStep Good
CustionStep Better (51 over 6"concrete slab)
CushionStep Best (50 over 6"concrete slab)
FlexStep Good
50 to 5153 to 54
Rotovinyls
Commission Plus - Discontinued
StrataMax Good
StrataMax Better
StrataMax Best
46 to 4950 to 53
Laminates
7mm, 8mm and 12mm laminate over Quiet Comfort Premium Underlayment
7mm: 56
8mm: 54
12mm: 53
49 to 56
Laminates (see Structure J)
7mm, 8mm and 12mm laminate over S-1836 Quiet Comfort Premium Underlayment
67N/A
Linoleum
    2.5mm Linoleum
    3.2mm Linoleum
    50 to 5353 to 56
    Engineered Hardwood with Underlayment
    (S-1836 Quiet Comfort Premium Underlayment)
    53 to 5652 to 53
    Solid Parquet with Foam BackingIIC: 55
    STC: 51
    N/A
    Carpet, directly applied (for reference)Equal to or greater than 55Equal to or greater than 55
    Rigid Core VantageIIC: 48
    STC: 50
    IIC: 50
    STC: 58
    Luxe Plank w/ Rigid CoreIIC: 53
    STC: 49
    IIC: 50
    STC: 56
    IIC: 67 (w. Drop Ceiling)
    STC: 62  (w. Drop Ceiling)
    Rigid Core ElementsIIC: 51
    STC: 49
    IIC: 51
    STC: 56
    IIC: 64 w. drop ceiling
    STC: 63 w. drop ceiling
     
    LVT with
    S-1840 Quiet Comfort
    Luxury Flooring Underlayment
    LVT AdhesiveUnderlayment
    6" concrete
    with ceiling
    3/4" Gypsum, 3/4" OSB,
     2x10 lumber with ceiling
    Natural Personality
    Natural Living
    Parallel 12
    Troweled
    S-288
    Armstrong S-1840 Quiet Comfort Luxury Flooring Underlayment 
    installed
    with S-288
    IIC: 64
    STC: 62
    IIC: 53
    STC: 57
    IIC: 53
    STC: 57
    Alterna 
    Alterna Reserve
    Engineered Stone
    Troweled 
    S-288
    Armstrong S-1840 Quiet Comfort Luxury Flooring Underlayment 
    installed
    with S-288
    IIC: 67
    STC: n/a
    n/a
    Natural CreationsTroweled 
    S-288
    Armstrong S-1840 Quiet Comfort Luxury Flooring Underlayment installed
    with S-288
    IIC: 65
    STC: 62
    n/a
    Luxe Value with Lynx
    Luxe Good with Lynx
    NoneArmstrong S-1840 Quiet Comfort Luxury Flooring Underlayment installed
    with S-288
    IIC: 65
    STC: n/a
    n/a
    Luxe with FasTak
    Natural Creations with I-Set
    NoneArmstrong S-1840 Quiet Comfort Luxury Flooring Underlayment installed
    with S-288
    IIC: 66
    STC: n/a
    IIC: 49
    Vivero Good (Glue Down)
    Vivero Better (Glue Down)
    Troweled S-288Armstrong S-1840 Quiet Comfort Luxury Flooring Underlayment installed
    with S-288
    IIC: 65
    STC: 63
    n/a
    Vivero Best
    (Glue Down)
    Parallel 20
    Troweled S-288Armstrong S-1840 Quiet Comfort Luxury Flooring Underlayment installed
    with S-288
    IIC: 66
    STC: 62
    n/a
    Vivero Good (Locking/Floating)NoneArmstrong S-1840 Quiet Comfort Luxury Flooring Underlayment
    Floating
    IIC: 66
    STC: 62
    n/a
    Vivero Better (Locking/Floating)
    Vivero Best
    (Locking/Floating)
    NoneArmstrong S-1840 Quiet Comfort Luxury Flooring Underlayment FloatingIIC: 68
    STC: 62
    n/a
    Luxe Rigid CoreNoneArmstrong S-1840 Quiet Comfort Luxury Flooring Underlayment FloatingIIC: 66
    STC: 60
    n/a



    TEST METHOD


    Unless otherwise designated, the measurements reported below were made with all facilities and procedures in explicit conformity with the ASTM designations E 492 and E 989, as well as other pertinent standards.


    STRUCTURE A - Flooring on 1-1/2" thick Gyp-Crete over 15# building felt on 5/8" plywood subfloor atop 2 x 10 wood joists on 16" centers with R-11 fiberglass insulation between, and one layer of 5/8" drywall ceiling hung from resilient metal channels fastened to the underside of the joists. (Typical California Floor)

    STRUCTURE B - Flooring on 3/4" thick Gyp-Crete on 3/4" plywood subfloor atop 9-1/2" deep "I" joists on 24" centers with R-11 fiberglass insulation between, and one layer  of 5/8" drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    STRUCTURE C - Flooring 3/4" thick Gyp-Crete on 3/4" plywood subfloor atop 9-1/2" deep "I" joists on 24" centers with R-11 fiberglass insulation between, and two layers of 1/2" drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    STRUCTURE D - Flooring on 1" thick Gyp-Crete on 3/4" plywood subfloor covered with Acousti-mat II underlayment atop 9-1/2" deep "I" joists on 24" centers with R-11 fiberglass insulation between, and two layers of 1/2" drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    STRUCTURE F - Flooring on 1-1/2" thick Gyp-Crete on 3/4" plywood subfloor atop 9-1/2" deep "I" joists on 24" centers with R-11 fiberglass insulation between, and two layers of 1/2" drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    STRUCTURE G - Flooring on 3/4" plywood subfloor atop 9-1/2" deep "I" joists on 24" centers with R-11 fiberglass insulation between, and two layers of 1/2" drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    Structure H - 6" Concrete slab subfloor

    Structure I - Flooring on 1” thick Gyp-Crete on 3/4” plywood subfloor covered with ¼” thick Acousti-mat II underlayment atop 18” open web wood joists on 24” centers with R-11 fiberglass insulation between, and one layer of 5/8” Type X drywall ceiling hung from resilient metal channels fastened to the underside of the joists.

    Structure J: 6 inch concrete slab with single layer of 5/8” Type X Gypsum Board on drywall grid system with 3-1/2 “ Fiberglass Sound Insulation








     
     
    Additional Information
     
    Floor CoveringDescriptionAdhesiveUnderlaymentSubstrateCeilingIICSTCDelta-IICYearTesting FacilityReport #sTest Date
    Biobased Tile- Striations12" x 24" (3.2mm)S-525None6" concreteNo335362015Architectural Testing Inc.F1725.01-113-11-R0/F1726-01C12/21/2015
    Biobased Tile- Striations12" x 24" (3.2mm)S-525None6" concrete
    with ceiling
    No5063n/a2015Architectural Testing Inc.F1725.08-113-11-R112/21/2015
    Linoleum Granette Tile12"x24" (2.5mm)S-780None6" concreteNo345482015Architectural Testing Inc.F1725.02-113-11-R0/F1726-01B12/21/2015
    Linoleum Granette Tile12"x24" (2.5mm)S-781None6" concrete
    with ceiling
    Yes4963n/a2015Architectural Testing Inc.F1725.09-113-11-R112/21/2015
    Adobe SheetSheet (0.5mm)Trowelable S-288 AdhesiveNone6" concreteNo3953122015Architectural Testing Inc.F1725.06-113-11-R0/F1726-01E12/21/2015
    Adobe SheetSheet (0.5mm)S-289None6" concrete
    with ceiling
    Yes5663n/a2015Architectural Testing Inc.F1725.07-113-11-R112/21/2015
    Natural Creations Earth Cuts 24"x24" (3.2 mm)Trowelable S-288 AdhesiveNone6" concreteNo3854112015Architectural Testing Inc.F1725.04-113-11-R0/F1726-01A12/21/2015
    Natural Creations Earth Cuts 24"x24" (3.2 mm)Trowelable S-288 AdhesiveNone6" concrete
    with ceiling
    Yes5163n/a2015Architectural Testing Inc.F1725.11-113-11-R112/21/2015
    Luxe with FasTak,
    Natural Creations with I-Set
    6” x 48” x .160" (4mm)NoneNone6" concrete
    with ceiling
    Yes53No Testedn/a2013Architectural Testing Inc.D3428.08-113-11-R012/13/2013
    Luxe with Rigid Core Technology48"x7"  (8.1 mm)Loose laidNone6" concreteNo  182017Architectural Testing Inc.G8312.022017
    Natural Personality 2 Trowelable S-288 AdhesiveNone6" concreteNo  32017Architectural Testing Inc.G9312.042017
    Pryzm48"x7" 
    (8.1 mm)
    Loose laidNone6" concreteNo  182017Architectural Testing IncG8312.052017
    Rigid Core Elements with pad5 mmLoose laidNone6" concreteNo  212017Architectural Testing IncG9312.012017
    User-added image
    Noise Reduction Coefficient (ASTM C-423)
    Test Lab: Architectural Testing, Inc.
    ProductOctave Band Sound Absorption Coefficients
    125250500100020004000NRC
    Armstrong Linoleum Tile0.010.010.000.020.070.090.05
    Armstrong Adobe Sheet0.010.000.030.060.050.060.05
    Additional Information
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