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What is IIC and STC rate for flooring system?

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Sound insulation products, such as underlayment, are commonly used in apartments, hospitals, schools, hotels, office buildings and customers who want quieter floors.  Sound insulation materials for impact sound insulation are designed to absorb and attenuate the sound generated by footsteps, falling objects, etc. on the floor surface.  Sound control standards were developed to regulate the amount of noise allowed to penetrate ordinary walls and floors within a home and to compare product quality. Under the current sound rating system, the higher the number, the better the sound suppression quality. In other words; As the number of ratings increased, the room grew quieter.  Large luxury apartment associations and municipalities usually follow * international building Codes or General Building Codes when setting sound control standards.  Many hotels now require sound control levels in the upper 50 or lower 60 range. Local municipalities can have different rating requirements. Impact complaints are common in floor-to-ceiling assemblies that meet the minimum 50 dB IIC requirement.

(IIC) Impact Isolation Rating *ASTM E492/E989 and (STC) Sound Transmission Rating ASTM E336/E413 are both sound tested through the entire floor/ceiling assembly from the upper living area to the lower living area.

The IIC test is for impact noise such as footsteps, moving furniture, things falling on the floor, etc. STC tests are for airborne sounds such as sound or music.  IIC and STC tests are conducted in a sound laboratory.

It is important to understand that IIC and STC tests are not for individual components of floor assemblies, but for the entire floor/ceiling structure, from the floor covering material surface of the upper unit to the ceiling of the lower unit.  Each IIC or STC test report published has a detailed description of the floor/ceiling components used in that test.  For engineered wood flooring installations, the outcome depends on the type of material used in the construction of the building and the substratum chosen for the application.

Test Standard

ASTM E492 Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine

ASTM E413 Standard Test Method for Classification for Rating Sound Insulation

How are the ratings calculated?

Both tests involve an apparatus in an upper chamber and a measuring system in the lower chamber. The frequencies are calculated by decibel measurements and ratings are calculated by a very complex mathematical formula. The higher the number, the higher the resistance – the better.


Post time: Nov-04-2021