Properties Of Wall Assemblies Fire Protection Data, Sound Data, And Energy Data For Masonry Walls

1) Fire Protection Data
2) Sound Data
3) Energy Data
4) Data Tables

2. Sound Data For Masonry Walls
(Noise Control)

2.1. Masonry structures are particularly well suited to the requirements of noise control in multi-family structures. Concrete block or brick wall assemblies provide a density of material with the noise reduction values needed to minimize tenant annoyance and comply with recognized standards. Sound transmission ratings are achieved with masonry construction for the reduction of the noise from freeways, rail movements, aircraft operations or nearby industrial activity. Sound rated masonry wall systems tested by application of standardized laboratory procedures are available to the architect for combating these exterior noise sources, as well as the undesirable sounds which may be experienced between dwelling units in multi-family construction.

2.2. Sound Transmission Control (Chapter 35 UBC)

Sec. 3501. (a) General. In Group R Occupancies, wall and floor-ceiling assemblies separating dwelling units or guest rooms from each other and from public space such as interior corridors and service areas shall provide airborne sound insulation for walls, and both airborne and impact sound insulation for floor-ceiling assemblies.

(b) Airborne Sound Insulation. All such separating walls and floor-ceiling assemblies shall provide an airborne sound insulation equal to that required to meet a Sound Transmission Class (STC) of 50 (45 if field tested) as defined in UBC Standard No. 35-1.

Penetrations or openings in construction assemblies for piping, electrical devices, recessed cabinets, bathtubs, soffits, or heating, ventilating or exhaust ducts shall be sealed, lined, insulated or otherwise treated to maintain the required ratings.

Entrance doors from interior corridors together with their perimeter seals shall have a laboratory-tested Sound Transmission Class (STC) rating of not less than 26 and such perimeter seals shall be maintained in good operating condition.

(c) Impact Sound Insulation. All separating floor-celling assemblies between separate units or guest rooms shall provide impact sound insulation equal to that required to meet an Impact Insulation Class (IIC) of 50 (45 if field tested) as defined in UBC Standard NO. 35-2. Floor coverings may be included in the assembly to obtain the required ratings and must be retained as a permanent part of the assembly and may be replaced only by other floor covering that provides the same sound insulation required above.

(d) Tested Assemblies. Field or laboratory tested wall or floor-ceiling designs having an STC or IIC of 50 or more as determined by UBC Standard No. 35-1, 35-2, or 35-3 may be used without additional field testing when, in the opinion of the building official, the tested design has not been compromised by flanking paths. Tests may be required by the building official when evidence of compromised separations is noted.

(e) Field Testing and Certification. Field testing, when required, shall be done under the supervision of a professional acoustician who shall be experienced in the field of acoustical testing and engineering and who shall forward certified test results to the building official that minimum sound insulation requirements stated above have been met.

(f) Airborne Sound Insulation Field Tests. When required, airborne sound insulation shall be determined according to the applicable Field Airborne Sound Transmission Loss Test procedures of UBC Standard No. 35-3. All Sound transmitted from the source room to the receiving room shall be considered to be transmitted through the test partition.

(g) Impact Sound Insulation Field Test. When required, impact sound insulation shall be determined in accordance with UBC Standard No.35-2.

Sec. 3502. Generic systems as listed in the Fire Resistance Design Manual, Tenth Edition, as published by the Gypsum Association may be accepted where a laboratory test indicates the requirements of Section 3501 are met by the system.

"Reproduced from the Uniform Building Code, with permission of the Publisher, the International Conference of Building Officials."

2.3. Sound absorption rating of finishes and furniture (NRC).

An estimate of the average sound absorption (average NRC) in a room may be obtained by multiplying the NRC value of each material in the room by its surface area, summing these (NRC x surface area) values and dividing this sum by the total surface area of the room.

The noise reduction provided by the sound absorption of furnishings within a room can be estimated by evaluating the average NRC.

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