Sound attenuation can affect two different types of treatment: The sound attenuation index rw is used to measure the ability of a material or product to reduce noise outside a room. It is therefore an acoustic insulation, which should not be confused with acoustic treatment. More precisely, this coefficient makes it possible to evaluate the performance of a wall separating two rooms or two buildings. Thus, the value of the complete sound attenuation of a glazing is calculated according to the following formula: Rw(C;Ctr). The sound attenuation rw is an index calculated according to a method to which we will return, used in certain specialties of acoustics. For acoustic treatment, the alpha-Sabine coefficient is used. Similarly, it will not deal with the reverberation time, but with the increase in decibels. However, like the alpha-Sabine coefficient, it calculates this decibel frequency gain (db) as a function of frequencies. Measured in the laboratory, these improvement indices of the sound attenuation indices Rw+C and Rw+Ctr represent the difference between the indices of a lined wall and an unlined wall versus pink noise and street noise. They are expressed in dB. Unique value of the sound attenuation index obtained by comparing the values of the attenuation index of the frequency band with the reference values (expressed in dB) It is a value measured in the laboratory that expresses the acoustic performance during the transmission of a product or a constructive system. This measurement is carried out without lateral transfers.

The conventional expression is R. This measurement makes it possible to compare the performance of different materials, products or building systems. R is given by the relation R = L1 – L2 + 10 log (S/A), where: – L1 and L2 are the sound pressure levels of the transmitting and receiving spaces (diffuse field), – S is the surface of the partition, – A is the equivalent absorption surface of the receiving room, – R is expressed in dB for a frequency or frequency band. Rw (C; Ctr), expressed in decibels, is calculated from the curve of R as a function of frequency. In recent years, gypsum board manufacturers have started to offer light drywall: normal weight gypsum has a nominal density of 43pcf and light drywall has a nominal density of 36pcf. This doesn`t have much impact on the STC rating, although lightweight gypsum can significantly affect the low-frequency performance of a bulkhead compared to regular gypsum. Ready to hear the difference? Contact one of our highly qualified acoustic specialists or fill out a free room analysis form to find the best acoustic solution for you! NRC`s ratings range from 0 to 1. An NRC of 0 means that the product does not absorb sound. An NRC of 1 means that the product absorbs all sound. The higher the NRC, the better the product sucks up the sound Capillary rise refers to the migration of water into the walls of a building from the basement. Its rate of evaporation depends on the ambient temperature and the humidity level of the air. The humidity present in the floor increases in the thickness of the low floor and / or peripheral walls and can reach all the walls of the dwelling, eventually leading to the deterioration of the building.

It is therefore necessary to provide waterproofing systems from the construction stage in order to avoid the phenomenon of capillary rise (waterproofing of basements, crawl spaces, rehabilitation by peripheral drainage). The calculation to convert Rw to Dw must take into account the following: Like the NRC and SAA coefficients, the rw index also has an indicator that calculates the average of the acquired database. We no longer focus frequency by frequency, but average over the entire frequency spectrum. This is called the weighted attenuation index of Rw. Therefore, it is important to perform these calculations correctly wall by wall and pay close attention to construction details in order to achieve a successful and cost-effective design. For example, a gain in decibels can be achieved for some frequencies and a loss for others.