In general the heavier a concrete masonry wall is the more effectively it will block sound transmission.
Stc concrete block wall.
Insulation will noticeably improve the stc rating of an assembly.
Installing insula tion within a wall or floor ceiling cavity will improve the stc rating by about 4 6 db which is clearly noticeable1.
Concrete blocks or solid partitions can be employed to separate boiler rooms air conditioning units work areas or noisy public areas such as stairwells corridors or lobbies from adjacent living areas.
For example a thick concrete wall will block more sound than a thin gypsum 2x4 wall.
Stc hollow with insulation 52 53 56 59 corefoam masonry foam insulationis an excellent product for improving thermal and acoustic properties of walls constructed with concrete masonry units cmu.
The stc of a wall is determined by comparing sound transmission loss stl values at various frequencies to a standard contour.
Staggered or double stud walls are higher rated than single stud walls.
The calculation in tms 0302 is based on a best fit relationship between concrete masonry wall weight and stc based on a wide range of test results.
Stc 20 50 234w eqn.
1 contains procedures for determining stc values of concrete masonry walls.
Resilient channel can improve the stc rating of an assembly.
However the additional weight added complexity of construction and poor thermal insulation tend to limit masonry wall partitions as a viable sound isolation solution in many building construction projects.
Metal stud walls perform better than wood stud walls.
The sound transmission class stc rating provides an indication of how effectively a given wall prevents sound transmission across a range of frequencies.
According to the standard stc can be determined by field or laboratory testing in ac cordance with standard test methods or by calculation.
When the mass of a barrier is doubled the isolation quality or stc rating increases by approximately 5 db which is clearly noticeable.
Due to increased mass poured concrete and concrete blocks typically achieve higher stc values in the mid stc 40s to the mid stc 50s than equally thick framed walls.
Mass is commonly added to existing walls by adding additional layers of gypsum.
Determining sound transmission class stc for concrete masonry sound transmission class stc provides an estimate of the acoustic performance of a wall in certain common airborne sound insulation applications.