Acoustiblok, a registered trademark of Acoustiblok Inc., is a barium free mass loaded construction membrane material which increases the sound attenuation properties of conventional wall and floor/ceiling designs. Acoustiblok material is also used as a component in noise abatement systems. It was introduced in 1999 and is manufactured in the United States.
Acoustiblok is a 1/8" thick mass loaded vinyl sound isolation material (16 or 32 ounces per square foot) that is barium free, used in architectural acoustics and other noise control applications. Acoustiblok is a dense but very flexible material, which controls sound energy by blocking airborne sound transmission, and dissipating acoustical energy by changing acoustical energy into a trace amount of heat through viscoelastic friction in response to sound waves. Sixteen ounce Acoustiblok is 0.1" (2.5 mm) thick, and weighs 1 lb/ft2 (4.9 kg/m2).
In common with all passive sound attenuation technologies, Acoustiblok material is more effective at controlling high frequency sound than low frequency sound, due to the higher energy of lower frequency sound waves. NVLAP certified laboratory tests by Riverbank Acoustical Laboratories, show that a single layer of 16 oz Acoustiblok reduces transmitted sound by 19 dB at 100 Hz, and 38 dB at 5 kHz. This report describes testing the Acoustiblok only, and not in an actual wall; construction assemblies with Acoustiblok give much higher sound attenuation.
The ability of a partition to block transmission of airborne sound is typically described by a single number rating, Sound Transmission Class (STC). Test procedures and the formula for calculation of STC values are defined in ASTM Standards E90-02 and E413-87. Sixteen ounce Acoustiblok material has an STC of 26.
The overall sound blocking capacity of a partition with Acoustiblok added cannot be calculated by simply adding 26 to the STC rating of a partition as found in reference sources, due to mechanical and acoustical variations in different partition wall and floor/ceiling designs, as well as the fact that STC is a logarithmic calculation and therefore cannot simply be summed. The most reliable comparative indicator of Acoustiblok's performance in practical application is laboratory measurement of the acoustical performance of test partitions. Field-measured sound isolation can vary considerably from lab measurements in any sound isolation protocol. This is generally due to installer error and flanking sound pathways, not as a result of the material failure in the field.
Adding one layer of Acoustiblok to a standard metal stud gypsum board interior wall, increases its STC to 53, which exceeds that of a 12" poured concrete slab, STC 51. STC is calculated using a range of frequencies similar to the human voice; attenuation in higher and lower ranges should be estimated from the Sound Transmission Loss graphs provided with standard STC reports.
Double steel stud partition walls, faced with single layers of drywall and containing fiberglass insulation and Acoustiblok, can achieve an STC of 66, sufficient to control the direct transmission component of high-frequency home cinema and industrial machinery noise.
Acoustiblok material is typically installed in partition walls and floor/ceiling assemblies during new construction or remodel/renovation work. The materials and techniques used in partitions incorporating Acoustiblok are determined by the minimum requirements for sound attenuation (STC), fire resistance (1 or 2 hour rated partition), and other application specific considerations (see UL Classification below). Acoustical test reports from NVLAP certified independent laboratories are available to specifiers, for a variety of commonly used partition designs with Acoustiblok added. Construction materials and techniques used in applications must conform closely to those used in tests, to obtain similar results.
Indirect transmission of sound through the frame, slab, windows, or other components of buildings, known as flanking paths, must also be addressed in cases where powerful noise sources and/or requirements for unusually quiet spaces exist. In these cases, there are no "quick fix" single product solutions; the structural design must be reviewed by a competent Acoustician, or an Architect or Engineer familiar with architectural acoustics. In these cases, Acoustiblok may be specified as an organic component of an integrated acoustical package.
Acoustiblok is qualified for use in commercial and institutional construction by its UL Classification file. under, Fire Tests of Building Construction and Materials. This Classification includes use in wall designs of the U300, U400, and V400 series, and floor-ceiling constructions of the L500 series, as specified in ANSI/UL 263 Fire Resistance Ratings. Ratings of 1 and 2 hours can be obtained, depending on specific partition design.
- http://acoustiblok.com/PDF/RAL-TL03-085.pdf RAL-TL03-085
- http://acoustiblok.com/PDF/RAL-TL04-050.pdf RAL-TL04-050
- Architectural Acoustics, M. David Egan, McGraw Hill 1988, pg 179
- http://acoustiblok.com/PDF/CNRC_B3431.3.pdf CNRC report B3431.3
- Architectural Acoustics, M.David Egan
- UL Classification file
- http://ulstandardsinfonet.ul.com/scopes/0263.html UL Standard 263
- ANSI/UL 263 Fire Resistance Ratings