Stc decibel reduction. The test results are available upon request.
Stc decibel reduction For an interior wall that is made of 3 5/8″ metal studs with one layer of 5/8″ gypsum board on both sides, the STC rating is about 38–40. Mar 6, 2018 · Keep reading for a basic run-down on the workings of the currently used STC system for the next time one of your buildings requires a test. e. While there is no completely soundproof window, the Sep 8, 2023 · Sound transmission class is a measurement of how well a solid building material attenuates airborne noise. read more STC is decibels (dB) reduction in noise a material/ partition can provide. Ref: (see ASTM International Classification E413 and Aug 21, 2023 · That is where NRC (Noise Reduction Coefficient) and STC (Sound Transmission Class) come to the table. STC ratings measure how much sound is being blocked, while decibels (dB) measure the volume of the sound. 3. A. Simply put, it measures how much sound a wall, for instance, will block from getting through the other side. STC and OITC are standards that measure sound attenuation. com 5500 77 Center Dr. FloorMat™ FanFold: FloorMat™ FanFold exceeds requirements for Uniform Building Codes with a 72-decibel IIC and a 67-decibel STC while improving R-Value. 98 (98% noise reduction). True B. info@greenfiber. A rating of 25 is no soundproofing, and 65 is complete soundproofing. The STC is a "one-number" average derived from sound attenuation values tested at sixteen standard frequencies from 125 Hz to 4000 Hz and indicate the product's sound barrier qualities. 3-08 Rev H 02/16 Superior Sound Control For glazing that is installed within a building interior, the Sound Transmission Class (STC) rating may be a more appropriate measure, as it describes the approximate decibel level reduction for the sound of human speech. What Is a Good OITC Rating for Windows? You can think of the STC rating as representing approximately how many decibels the partition can drop the noise. With an attic or rafter space at least 6” deep and with a ceiling below, the roof shall consist of Jul 23, 2023 · Sound Transmission Class (STC) In the United States, a common way of comparing sound insulation in buildings is using a measurement called STC (Sound Transmission Class), which describes how well or badly sound waves (broadly in the range of normal human voices, 125–4000 Hz) travel through ceilings and walls. With either scale (the OITC scale for exterior glazing or the STC Jan 20, 2022 · The factors that contribute to calculating the STC rating of a surface are: Decibels: This acoustic measurement calculates a noise’s volume — the higher the decibel level, the louder the noise. 501 re 306 396. I don't want to do all this work and spend all this money if I'm still going to have loud noises I can hear. May 6, 2024 · Acoustical design plays a major role in helping people feel comfortable and relaxed at work, school and home. Explore our STC-rated assemblies and learn how SONOpan can help you achieve optimal sound control for any environment. ˚is is an integer rating how well a building partition reduces airborne sound. Mecart’s standard acoustic products are labelled STC-35, STC-45 and STC-52. Jan 18, 2024 · If you look for best possible noise reduction, you should check our soundproofing acoustic panels. components. However, a 10 dB reduction is perceived as being half as loud. b. Enhancing the sound transmission class of a partition can be achieved through various methods, including the addition of mass and an increase in overall thickness. A good level of isolation for walls and ceilings is STC 50 plus. This means that increasing a wall’s STC rating from 33 to 53 (20 dB) results in a 75% reduction in perceived sound and increasing to an STC 63 (30 dB) results in a 88% reduction in perceived sound transferring through the wall! Dec 30, 2022 · The ISO Sound Reduction Index (SRI) is applied outside the United States. Feb 19, 2022 · In most other countries, the Sound Reduction index is used (SRI). STC ratings for concrete masonry walls are determined using Standard Method for Determining the Sound Transmission Class Rating for Masonry Walls, TMS 0302 (ref. . The same process is used to determine STC ratings for doors. Feb 16, 2024 · If the room that is producing the sound is at a decibel level of 80 db and the adjacent quiet room needs to be at 40 db, all you need is an STC rating of 40-50 to achieve a balance. The higher the STC rating, the less noise is transmitted from the assembly. We’ll also explore how Altispace Acoustic Shapes, Blades, and Fins can contribute to acoustics with their impressive NRC rating of 0. This is a United States standard scale: the higher the number, the better that material can reduce sound by reducing the frequency and decibels. Increasing the mass of a partition B. 2 Sound transmission loss (TL) is a standardised measure of the noise reduction in decibels for specific frequency ranges. 5). Suite 100, Charlotte, NC 28217 PM-6. So, a higher STC number means more sound blocked. A 70dB noise with a STC20 product would yield about a 50dB end result- or a perceived reduction of 75%. ft. The ratio of the sound energy striking the wall to the transmitted sound energy, expressed in decibels (dB), is called the transmission loss (TL). For example, if an 80 dB sound on one side of a wall/floor/ceiling is reduced to 50 dB on the other side, that partition is said to have an STC of 30” STC is the most common sound reduction measurement in use. 9 test for at least one week. Dec 18, 2023 · The STC rating provides a rough indication of the decibel reduction of noise achievable by a partition, particularly in relation to speech sounds. Frequency. For example, an STC rating of 50 means that the partition reduces sound by 50 dB. For example, a 20 dB sound is ten times more intense than a 10 dB sound. The STC rating for a basic wood structure floor/ceiling is STC 40-43. The STC rating figures reflect the decibel reduction in noise that a partition can provide. Price R-STC Silencers provide noise reduction performance meeting STC 40, 45, 50, and 55 ratings as required. Simply put, it measures how much sound a wall, for instance, will block from getting through to the other side. Sep 27, 2024 · STC ratings are determined through a series of tests that involve measuring the decibel reduction of sound as it passes through a material. A higher sound transmission class rating indicates more effective sound insulation than a lower number. The sound transmission class (STC) rating provides an indication of how effectively a given wall prevents sound transmission across a range of frequencies. The two concepts are related but not identical; acoustic absorbers can both have a high STC rating and reduce decibels. This guide will help you navigate these ratings and ensure you specify the best solutions from ADL’s custom acoustics product line for your projects. Explore noise reducing windows and doors from Pella. The NRC how much sound intensity they block. Our STC-rated wall assemblies and ceiling assemblies are designed to provide excellent sound attenuation and noise reduction, but the best results are achieved by combining different materials. While STC is specified in some regulations and guidelines, there is no direct correlation between STC and the noise reduction achieved with most exterior sources. STC rating goes from 25 – 65. 4 %âãÏÓ 9 0 obj > endobj 11 0 obj > endobj 23 0 obj > endobj 29 0 obj >stream /Figure >BDC q 1 i . The higher the STC rating, the better it will reduce noise. It might sound a bit confusing, but it is actually quite simple - STC ratings are used to determine how many different types of materials can reduce sound waves coming from different sound frequencies. Feb 18, 2022 · In most other countries, the Sound Reduction index is used (SRI). The STC value approximates the decibel reduction provided by that particular partition. ) based on its ability to reduce sound coming through it. Need-to-Know Abbreviations: STC – Sound Transmission Class; Hz – Hertz; dB – Decibel; TL – Transmission Loss; For more advanced concepts, consider looking at our Soundproofing Case Studies or Study with Quizlet and memorize flashcards containing terms like The more elastic a substance, the better it is able to conduct sound waves. Sound frequency is measured in Hertz (Hz) and determines the pitch of the STC ratings are used for windows, doors, walls and most building materials. STC is a measure of how much noise reduction a product renders. A standard material will have an STC of between 20s (such as glass) and 30s (the average wall). OITC correlates well with the noise reduction achieved. Consider these common sound thresholds: 10 dB: Sound is now audible; 35 dB: Whisper volume Overview. The STC is adequate for assessing discomfort caused by speech sounds, not music or equipment noise since these sources include more low-frequency energy than speech. These products have been around long and are easy to use and effective. These tests are usually conducted across a range of frequencies to provide a comprehensive understanding of the material’s soundproofing capabilities. Construction materials companies use a rating system called Sound Transmission Class levels, or STC, to determine how effective a product is at blocking noise or creating transmission loss. In order to better conceptualize STC ratings beyond the basics described above, it’s important to have a working understanding of decibels, transmission loss, and frequency. The Sound Transmission Class (STC) rating measures a window's ability to reduce airborne sound. Apr 4, 2023 · Natura’s professional grade successor, Natura Elite™, offers 70-decibel IIC, 65-decibel STC and 21-decibel ΔIIC ratings. Decibels (dB) Decibels are the units used to measure the intensity of sound. Call for your Noise Reduction Solution, 1-800-513-9425! The noise reduction coefficient (NRC) is associated with the material’s capacity to absorb noise and is frequently rated on a scale of 1 to 10, whereas the sound transmission class (STC) is associated with the blocking capability of any substance, particularly isolating material used as a separation, and evaluated on a scale of 100. com www. When installed on studs or joists, Trusscore Wall & Ceiling Board has an estimated STC value of 30 to 35 (i. Skylights shall conform to an STC rating of at least 28 2. To the sion Class (or STC) in the U. Address: 6301 N Florida Ave Tampa, FL 33604 STC Sound Control offers Noise Control Products that help meet code requirements while maintaining privacy in Apartments. With noise pollution cited by the World Health Organization as one of the leading environmental causes of health problems such as high blood pressure, increased stress and poor sleep, it has never been more important to understand the alphabet soup that makes up acoustical ratings. Of course, the rating is determined as an average based on the different frequencies between 125 Hz to 4000 Hz. The higher the rating, the less noise penetration. Winners: There is no noticeable disparity between each of the rug pads’ STC ratings. Nov 25, 2022 · The difference between the sound level inside the window and the sound level outside the window, measured in decibels, is the STC rating. Fiberglass Installation Factor Impact on Sound Reduction; Density: 35-40 STC Rating: Typical Thickness: 3. While there are a lot of materials that have their own STC ratings, they can also combine in the form an STC rated wall or floor/ceiling assembly. 2. But as soundproofing needs evolve, Mute-X’s advanced solutions are even better. Here’s a table showing what each STC rating represents: Oct 10, 2024 · An example would be a 70dB noise with a STC30 product would yield about a 40dB end result – or a perceived reduction of about 85%. Decibels. Here’s a table showing what each STC rating represents: Legal Name: STC Architectural Products LLC Assumed Name: STC Sound Control 1200 Northland Ave. STC ratings are given as a whole number – higher is better. However, it should be noted that these are three distinct terms for measuring different aspects of acoustics by voice, decibels (dB), and material sound absorption. Mar 21, 2021 · It assesses how much a material can reduce airborne noise. ). section (Ceilings), shall have a laboratory sound transmission class (STC) rating of at least 39. STC is an attribute of a wall or floor-ceiling assembly that measures the made duct, specifically designed to meet the 25 decibel noise/sound attenuation requirement may be substituted for 20 gauge steel duct. In the USA, it is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations. Higher STC ratings mean better soundproofing. Buffalo, NY 14215 Telephone: 716-839-0900 E-mail: info@stcsoundcontrol. Sound Transmission Class (STC) The STC rating is a single number rating that indicates how well a building element attenuates airborne sound. 228. With either scale (the OITC scale for exterior glazing or the STC Jan 28, 2024 · STC stands for Sound Transmission Class and refers to how much sound is being stopped by a surface or a specific material. , it reduces 30 to 35 decibels of sound), which is similar to the sound blocking performance of single-layer drywall. For example, a whisper is 30 decibels while a rock concert can reach dangerous levels of up to 140 decibels. Sound Transmission Class or STC is an integer rating of how well a building partition attenuates airborne sound. Dec 20, 2022 · Sound Transmission Class (STC) STC (Sound Transmission Class) represents a material or product’s ability to block sound from travelling through a wall, ceiling, floor or other building assembly – in other words, to stop airborne noise transferring from place to place. STC stands for Sound Transmission Class and is a common sound measurement — find more details in “How to compare soundproofing” below. In comparing sound absorbing materials for noise Determine as best you can the amount of decibel (noise) reduction you wish to achieve for your application. Sep 10, 2023 · Indow can reach an STC of 45 and costs $31 per sq. The Rw equivalent would be Rw 46 or 47 Maximize noise reduction in your home with effective soundproofing insulation options like fiberglass and mineral wool, achieving STC ratings up to 63. Here’s a table showing what each STC rating represents: May 22, 2022 · The noise reduction characteristics of different materials are measured on a scale called the Sound Transmission Class or STC levels. Although this is a rule of thumb, it helps give some intuition for what STC rating numbers mean. A good STC rating shows how well a building can attenuate sound. The Sound Transmission Class is always reported as a whole number. As previously explained, this means they have been tested in a laboratory for their sound transmission loss. 0024 greenfiber. See full list on acousticalsurfaces. The STC rating figure represents approximately the decibel reduction in noise that the assembly can provide. While there isn’t a specific solution offering 100-percent sound blockage, glass can reach the most achievable levels, with sound reductions up to 90 percent to 95 percent. Materials are tested in a lab against frequencies ranging from 125 Hz to 4000 Hz, and the resulting curve is used to calculate the rating. Acoustic metrics sound transmission class (STC) and noise reduction class (NRC) (defined below) have been specifically developed to quantify these properties. 4. It is the most common sound measurement system in North America – that Phone: 888-815-9691. Dec 4, 2024 · Les valeurs du STC sont généralement plus élevées d'environ trois à quatre décibels par rapport à celles de l'indice de réduction sonore pondéré (49 dB STC = 44 dB Rw). Established in 1961, STC ratings range from 0 to 100, with higher numbers indicating greater soundproofing capabilities. The STC rating reflects how much noise reduction is achieved, and it’s often presented in dB. Mar 23, 2017 · • SOUND TRANSMISSION CLASS (STC) –An integer rating of how well a building partition such as an interior wall, floor/ceiling, door, window, or exterior wall attenuates airborne sounds ranging between 125 and 4,000 Hz. Jun 4, 2024 · STC Rating vs. Based on the desired noise reduction, specify the STC or OITC that is required of the glazing system. The bigger the loss intensity, the better the material at noise reduction, thus a higher STC rating. greenfiber. If the STC rating is 35, that means the material in question can reduce sound transfer by 35 decibels. By taking the transmission loss values and testing them at 18 of the most common frequencies (between 125 Hz-4000Hz), a curve is created, which is then compared Apr 6, 2023 · 1. Jun 4, 2024 · With regard to wood soundproofing, the STC reduction of any given wood type is a rough estimation of the net decibel noise reduction it will provide if you use it in a partition. Certains experts préfèrent toutefois l'indice de réduction sonore pondéré car il est synchronisé avec l'échelle des décibels. STC ratings are the ONLY way to accurately compare various noise reduction products. 5″ (R-13) to 6″ (R-19) Air Gap Size: 1-2 inches optimal PDF-1. com STC Sound Control makes acoustical products for architecture that minimize the annoyance and aggravation related to noise…. “An STC rating roughly equals the decibel (dB) reduction in noise volume a wall or partition can provide. False, Ways to isolate sound include all but which of the following: A. d. A window with an STC upgrade combines glass panes with mismatched thicknesses. S. Sound Transmission Class (STC) The STC is a value used to rate how effective different materials or combinations of materials are at improving the sound transmission loss (TL) in decibels (dB). Oct 21, 2013 · The STC rating figure very roughly reflects the decibel reduction in noise that a partition can provide - Wikipedia 10/21/2013 . NWTL140828-03 STC 40 Assembly Components Finish material 1/ Noise reduction (NR) Sound Transmission Class (STC) Impact Isolation Class (IIC) Transmission Loss (TL) - correct answer (T/F) Elevators can be designed as passenger or freight elevators or a combination of the two. What is sound transmission class (STC)? STC is a measure of how well a wall or building partition reduces sound from traveling through the building. com Jun 15, 2024 · The Sound Transmission Class rating system is the most common sound reduction measurement and offers a standardized method for measuring the sound reduction capabilities of building partitions. Is the 4-point increase worth an extra $70? Probably not, unless you’re dealing with particularly loud and annoying noise pollution. The STC is given as an integer rating and can compare rug pads to find out how soundproof they are. Sound Transmission Class (STCJ For significant noise reduction between two rooms, the wall (or floor) separating them must transmit only a small fraction of the sound energy that strikes it. In this guide, we’ll delve into the significance of these ratings. Oct 20, 2024 · What is the required Sound Transmission Class (STC) rating for the walls to achieve a sound reduction of 25 decibels? What is the calculated STC rating for a wall assembly consisting of two layers of 2-inch-thick fiberglass with an air space in between, and a total thickness of 8 inches? Nov 16, 2024 · Before selecting noise-reducing windows, it's important to understand how sound is measured and how different windows can affect noise levels inside your home. Sound Transmission Class Rating and Noise Reduction Coefficient are some soundproofing terms to recall. The higher a material’s STC rating, the more sound it blocks. It’s called an STC upgrade. STC – Sound Transmission Class. Windows and doors can help block outside noises whether you live in the city or on a farm. For glazing that is installed within a building interior, the Sound Transmission Class (STC) rating may be a more appropriate measure, as it describes the approximate decibel level reduction for the sound of human speech. Feb 25, 2022 · In most other countries, the Sound Reduction index is used (SRI). The STC rating reflects the decibel reduction of noise that a partition can provide (1 STC is equivalent to 1dB reduction), where a higher number, or rating, equals better results, or overall attenuation. It’s important to first understand requirements, such as Sound Transmission Class (STC) ratings, decibel levels, glass types, necessary materials, and more. STC or sound transmission class is defined as the level of reduction of sound transmission from outside noise sources to the building interior. STC Precepts. 800. The acoustical terms used in this Digest such as decibels (abbreviated dB), were discussed in detail in Canadian Building Digest 236. This type of assembly is much easier and less expensive to build than an STC-70 wall. The STC ratings allow accurate 'apple to apple' comparisons. Most of the time, an assembly’s OITC rating is lower than an STC rating. The sound transmission class rating approximates the decibels of noise reduction that a partition may give. Determine the noise reduction that is required of the glazing system. com. Whether you’re setting up a recording studio, improving your home’s acoustics, or soundproofing industrial spaces, a soundproof blanket is often the go-to solution for noise reduction. This sound rating increases to STC 42-45 with steel studs. An Impact Insulation Class (IIC) rating indicates the indicates the indicates the indicates the block sound impact and measures resistance to resistance transmission of impact noise objects dropped on the floor, etc. Feb 19, 2024 · The STC rating is based on how many decibels can be reduced through a material. Dec 3, 2022 · In most other countries, the Sound Reduction index is used (SRI). Sep 17, 2018 · What we mean when we say STC-35, STC-45 and STC-52. Isolating air space within a During testing for STC & OITC, the sounds used are different, STC tests between 125 to 4000 Hz and uses interior noises such as talking, television, or typing, OITC tests between 80 to 4000 Hz and uses sounds like train whistles, street noise, or air traffic. Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates airborne sound. When using this rating, the number is considered. This airborne sound reduction efficiency is expressed as Sound Transmission Class (STC). • Standard double-pane glass = STC-32 • Thick laminated glass = STC-39 • Limits the allowable glazed areas • For B, C or D, determine exterior noise using ANSI/ASA S12. Noise Reduction Coefficient (NRC) Oct 18, 2023 · An outdoor-indoor transmission class rating chart is used to understand the decibel scale and its relation to OITC ratings. Feb 3, 2025 · Noise reduction has a rating in terms of the Sound Transmission Class (STC). This implies that the higher the number, the better the material's ability to reduce the sound by causing a reduction in both the decibels and the frequency. The test results are available upon request. A standard wall will have an STC rating of 35-45. 751 614 -426. DECIBELS: A decibel (dB) is simply a measurement of how loud a noise is. STC 43 Assembly Components Finish material 5/8” Gypsum Size 3 5/8” Steel Stud Spacing 16” oc Product AFB Thickness 3. OITC (Outdoor-Indoor Transmission Class) is a more modern and “real world” test that includes sounds on the lower end of the spectrum, from 80 to 4000 Hz. For example, a wall with an STC rating of 50 is better at blocking sound than a wall with an STC rating of 30. This occurs for most road noise but an exception is high-speed freeway sound dominated by tire noise. Background: terms such as Sound Transmission Class (STC), Noise Criteria (NC), and Noise Reduction Coefficient (NRC). A sound reduction of 35 decibels is very high. Apr 14, 2022 · Some low STC rated products include glass windows and hollow-core doors, while some high STC rated products include mass loaded vinyl and solid-core doors. 5. For windows, STC ratings range from 18 to 38. An STC rating is an instrument measurement of how much noise is stopped. In the US, it is widely used to rate interior partitions, ceilings, floors, doors, windows and exterior wall configurations. This means that each increase of 10 dB represents a tenfold increase in sound intensity. A high level of isolation for walls is STC 60 plus with ceilings at STC 50 plus. Sound Transmission Class (STC) = (16) Frequency Average 10 0 12 5 16 0 the noise exposure that is anticipated. A higher sound transmission class rating indicates more effective sound insulation than a lower rating. Prescriptive Standard a. Dec 7, 2023 · A sound transmission class chart is a simple way to understand the decibel scale and its relation to STC ratings. A Jun 12, 2024 · The sound transmission class (STC) measures how well a material or building partition reduces airborne sound. Sound Transmission Class (STC) Rating. But dry walls have resonance issues. Drywall with average thickness has an STC of around 36 in the USA. Outside the US, the ISO Sound Reduction Index (SRI) is used. As common as this measurement is, it is quite limited and should not be totally relied upon for real-world soundproofing expectations. For example if your source room is expected to generate 90 dB of “noise” and you want to reduce sound transference to 40 dB then you will generally require a “minimum m” STC 90 - 40 = STC 50. Structure borne noise is generated when a mechanical force is applied to a structural building element, such as through footfall noise, hammering a nail into wood studs, or mechanical The concepts of Noise Reduction Coefficient (NRC), Sound Transmission Class (STC), and other acoustic ratings are vital in designing spaces that meet your acoustic and aesthetic requirements. It’s a rating you’ll want to pay attention to, especially if you’re looking to insulate a room against speech sounds. STC is measured roughly by the decibel reduction in noise a material/partition can provide, abbreviated 'dB'. 5” Acoustics Assembly Number: ISS-02 STC: 43 OITC: 28 Report No. The STC number is the decibel (dB) reduction across a material or assembly. Sound Transmission Class (STC) Sound transmission class (STC) is the standard rating in the United States. The first is the STC rating. 06 m W* n 0 792 612 STC rating (Sound Transmission Class rating) is a score given to a building’s surface (wall, ceiling, window, etc. This can be done using estimation techniques or actual on-site noise measurements. So, in this case the 10 STC points is only a slight change in the original sound. The material is used in the wall or floor that separates both rooms. These have NRC 0. Some examples of STC reduction values are: Impact-Related Sounds. STC ratings were introduced in 1961 as a way to compare different types of walls, ceilings, floors, doors, and windows. Widely used STC (Sound Transmission Class) measures frequencies from 125 Hz to 4000 Hz. As an example, let’s take a typical single-pane window and a masonry wall. Here’s a table showing what each STC rating represents: In sum, STC tells you how much a ceiling or wall might stop sound. Assemblies will be organized by STC value ranging from an STC of 40 to an STC of 57. General trends are presented here in terms of the sound transmission class (STC), which Nov 25, 2024 · A quiet space in a noisy world seems impossible. , or the Sound Reduction Index (SRI) outside the U. Soundproofing materials often come with a Sound Transmission Class rating (STC). My room might achieve STC level 60; but I might might only get a 20dB reduction in low frequency banging. These panels absorb indoor and block outdoor noises! Sound Transmission Class or STC rating. STC is a rating of how well a building partition attenuates airborne sound. The STC rating for a six inch concrete sub-floor is 52-55. May 22, 2022 · The STC measures how different materials or barriers interact with 16 different frequencies. Where to Buy High-Performance Noise Reduction Underlayment On the decibel scale, 0 dB is identified as the smallest audible sound, and it’s important to note that this scale is logarithmic, not linear. e. For example, if the transmitter played a sound at 60 decibels and the receiver picked up 30 decibels, the STC rating would be 30. 8. May 13, 2022 · Sound Transmission Class (STC) A Guide to True NRC™ Acoustic Rating. Thickness We offer a type of window glass option that’s specially designed to reduce sound. This consists in measuring the loss in sound intensity (in deciBel) between two rooms. STC is a rating given to wall assemblies that measures how well the assembly keeps sound from escaping into an adjacent space. Email: info@commercial-acoustics. On the other hand, Acoustical Solutions can reach an STC of 49 and costs, roughly, $100 per sq. Decibels - Indicated at dB, a decibel is a measurement of how loud a sound is. 50003 659. A material’s STC reflects a sound’s decibel reduction from the space where the sound originates to the adjacent space. May 13, 2021 · Sound Transmission Class (STC) Sound Transmission Class, abbreviated STC, is the measurement of a material's ability to block airborne sound within the frequency range of human speech. Listed factory-made duct, specifically designed to meet the 30 decibel noise/sound attenuation requirement, may be substituted for 20 gauge steel duct in items (a) and (b) above. Aug 29, 2016 · SOUND TRANSMISSION CLASS (STC) – An integer rating of how well a building partition such as an interior wall, floor/ceiling, door, window, or exterior wall attenuates airborne sounds ranging between 125 and 4,000 Hz. ˚e STC rating roughly re˜ects the decibel reduction in noise that a partition provides. An STC rating is a single number value indicating the sound isolation properties of a building element (wall, slab, etc. False, A higher CAC rating indicates that a ceiling system allows more sound transmission. mffjxe lnqp bqvtif raao atakjps hwev wsla ybwq jzc jyle cemzq lpxbjfh umtkn xujcae woccd