Acoustic oitc rating chart pdf. The chart below summarizes Halio’s STC and OITC ratings.
- Acoustic oitc rating chart pdf The OITC rating scale captures transmission loss results between 80 and 4,000Hz. This occurs for most road SITE EXTERIOR NOISE - OITC/STC of façade (H,OP,R) • Issue: Outdoor Indoor Transmission Class criteria are more appropriate than STC for façade evaluation, but test data are sparse • Resolution: 2010 Guidelines listed STC, 2014 Guidelines listed OITC, 2018 will list both providing guidance on how to select. When 1• double laminated insula1ing glass (1/4" laminated glass-1/2" air space-114• laminated glass) is used instead, the STC rating increases to 38. The formula to calculate OITC from TL test results is: OITC = 100. Unfortunately, until now this information has been Sound levels may also be presented using Noise Criteria (NC) ratings, which is single-number metric calculated using the sound level frequency spectra between 16 STC_MTC_OITC_RW - Free download as PDF File (. An outdoor-indoor transmission class rating chart is used to understand the decibel scale and its relation to OITC ratings. Actual performance in real-lif. Because of the larger range in expected sound, OITC values are determined for lower frequencies as well, in the range of 80 to 4000 hertz. Composite OITC Rating (OITC C) A Minimal 25 B Moderate 30 C Significant 35 D Extreme 40 2. 0024 greenfiber. For more details, download the Halio Acoustic Performance datasheet here: Acoustic Doors Inoperable Test vs. This document provides information on calculating various acoustic transmission ratings including STC, RW, MTC, and OITC. Address: 6301 N Florida Ave Tampa, FL 33604 The OITC (Outside-Inside Transmission Class) rating is used to classify acoustic performance of glazing in exterior applications. Use OITC when considering intrusion of noise into a building from roads,trains or aircraft. The ability of a barrier to create a specific decibel deficit varies according to the In some cases you can achieve a higher sound reduction rating using a single piece of acoustic glass as opposed to a sealed unit. The frequency content of many common exterior sounds closely resembles that used for the OITC rating. * * [The data and information set forth are based on samples tested and are not guaranteed for all samples or applications. Sound Control Sell Sheet [PDF] SELECT ALL DOWNLOAD SELECTED. TubeliteUSA. In the case of both STC and OITC ratings, a higher the rating, the better as it indicates that less noise is detectable. The target STC values were 45 - 50 and for OITC the target values were 35 - 40. Glass size and glazing system will affect STC rating. 70 60 --STC38 Most standard product acoustic tests are run at the standard sizes cited in ASTM E1425 Standard Practice for Determining the Acoustical Performance of Windows, Doors, Skylight, and Glazed Wall Systems, which The document discusses methods for calculating various acoustic ratings including STC, RW, MTC, and OITC. An OITC rating is best assigned to specimens tested in the laboratory. Other ratings may be computed using the same worksheet subsituting the appropriate data for the rating instead of the sound transmission loss. com Page 1 of 1 www. To determine the specific STC ratings of glass and a window or door assembly, the following ASTM standards can be used: • ASTM E 90: Standard Test Method for Laboratory Measurement of Airborne Sound Transmission OITC is one rating system available to help compare the acoustic performance of various wall systems. STC measures sound insulation from 125Hz to 4kHz and is calculated by comparing measured transmission loss data to reference curves. Sound Transmission Class (or STC) is an integer rating of how well a building partition attenuates airborne sound. Comparing STC and OITC Ratings of Different Window Types 4. The STC is determined by comparing its sound transmission curve with a standard reference curve. Explore noise reducing windows and doors from Pella. bands from 125 Hz to 4000 Hz. These ratings are all single numbers used for comparison of various assemblies. 3-08 Rev H 02/16 Superior Sound Control How the OITC Rating is Measured Like the STC rating System, OITC measures sound intensity loss in decibels. The higher the STC value, the better the wall assembly is at reducing sound. TMS 302-18 is adopted by reference in the 2021 Desired Acoustic Value. Sound Transmission Class (STC)—measures sound transmission of interior spaces with frequencies ranging from 125 to 4000 Hz; higher STC numbers mean less sound is transmitting beyond an interior space. 24 Page 1 of 2 Due to continual product research and development, details listed are subject to change at any time. (2) Not available for knock down frame. 22. includes both STC and OITC ratings for steel and wood stud walls, considering both interior and exterior assemblies. STC 72 Wall Only. Acoustical Ratings - Tuscany I V400 updated 09. • Implications: transmission class (OITC), with higher OITC values indicating better sound insulation. Acoustic labs conduct the IIC test using a tapping of about 20 to a high of 55. construction, and methods to STC and OITC rating for concrete masonry and clay masonry assemblies. V300 | TrinsicTM Series Acoustical Ratings of acoustic glass with high ratings. In addition, Each assembly references an RWT (ROCKWOOL test) number. Simply type into an acoustic value we need, the system list all the matched compositions. Sound Control Specifications [DOC] SELECT ALL DOWNLOAD SELECTED. When evaluating the soundproofing needs of a space, it’s essential to understand the distinction between Sound Transmission Class (STC) and Outdoor-Indoor Transmission The goal of the project was to test wall and roof assemblies that (1) meet today’s energy codes, (2) determine sound rating improvement with various layers of gypsum board, and (3) incorporate fire rated assemblies, where possible. Outdoor-Indoor Transmission . determine sound rating improvement with various layers of gypsum board, and (3) incorporate fire rated assemblies, where possible. 030 pvb - 3mm + 3mm The OITC (Outdoor Indoor Transmission Class) rating was created to test exterior walls and their elements (windows and doors). The STC This Acoustics Wall Assemblies Catalog provides a comprehensive list of wall assemblies tested for their acoustic performance. J2247-13-303-11-R0 Insulation Included STC 24 / OITC 18 No Insulation STC 29 / OITC 20 R-10 Faced 202-96 Insulation Over the Purlins STC 32 / OITC 22 R-19 Faced Insulation Over the Purlins STC and OITC Ratings for Typical Metal Building Constructions Walls Roofs STC 54 / OITC 39 R-13 Faced 202-96 Insulation Over the Girts 3 5/8” Steel Studs on 24” Centers with R-11 Batts and 1/2 Our acoustic-specific product, It also posted an OITC 52 rating. txt) or read online for free. It explains: 1) The STC and RW ratings are based on comparing measured transmission loss data to numbered reference curves, with the number of the best Sound Attenuation Batt Insulation Product Data Sheet Description Acoustic Comparison of Cavity Insulation Types Sound Attenuation Batts (SAB’s) Gypsum Board Insulation Type Test Number STC are unfaced, lightweight, fl exible One layer each side. Email: info@commercial-acoustics. OITC Ratings. The STC rating has been around for decades and is often relied upon as the go-to rating for soundproofing a building. The OITC rating system is designed to evaluate the soundproofing effectiveness of building materials against common, Phone: 888-815-9691. The tested STC ratings were less than the manufacturer's published STC ratings. The STC rating for a basic wood structure floor/ceiling is 40-43. Intertek Testing Locations: A standard dual-pane window carries an STC rating of around 27, but requesting the appropriate options can boost that value up to around STC 34. OITC. The results express in decibels as opposed to the point system used to determine STC ratings and with weighting more towards low frequency performance. Outdoor-Indoor Transmission Class (OITC) Recently, a new single-number rating has . with single laminated glass Laminated: 3mm - 0. 14a Laboratory measured STC and OITC ratings and Rw for various glass configurations. STC is a method of rating airborne sound transmission performance of a wall or fl oor assembly. MTC was developed to address shortcomings of STC and The STC (Sound Transmission Class) rating is a single-number rating system for interior building partitions and viewing windows used to categorize acoustic performance. Dissimilar glass. Frequency, Decibels, rating. If a 105-decibel above ground subway only registers as 80 decibels after traveling through a Window or wall, the sound experiences a 25-decibel deficit. These STC and OITC values are common requirements in today’s commercial construction. Department of Housing and Urban Development (HUD) provides information on housing policies, programs, and resources. It is calculated based on ASTM E 1332 using sound transmission loss data measured between 80 – STC/OITC rating of the window assembly will typically be reduced from the base glass acoustical rating. Sound transmission loss measurements may be conducted at some lower frequencies if requested in advance. TD-138 - Heat Treated Glass for Architectural Glazing -114• glass) with an STC rating of 34. We can choose the glazing type based on Single, Double, Glass Thickness, Glass Weight, etc. 5” Acoustics Assembly Number: ISS-00 Befitting the therapeutic environment, LEED® for Healthcare awards up to two points for EQ Credit 2: “Acoustic Environment: Exterior Noise, Acoustical Finishes and Room Noise Levels” after rigorous determination of exterior noise levels, acoustic design of the total building envelope, and measurement of “as-built” sound pressure levels. Due to ongoing product changes, updated test results or new industry standards or requirements, this data may change over time. The four-point increase in STC rating is the resuH of dampilg provided by the PVB intedayer used in the laminated glass. It is used to specify the sound transmission loss properties of exterior E413-87 in an ac oust ical wall. The sound attenuation properties of a glazing type will be achieved with the plastic interlayer I. It uses a specific decibel (Db) range (80 Hz to 4000 Hz) which makes it a better measure for low sound frequencies such as road tested for their acoustic performance. Sound Rating. Suite 100, Charlotte, NC 28217 PM-6. The ability of a barrier to create a specific decibel deficit varies according to STC OITC Test Date Test Number Operating Style Series Numbers Tested Size OA Glass 1 Glass 2 Acoustical Ratings - Ultra I C650 updated 04. 5” Acoustics Assembly Number: ISS-00 STC: 43 OITC: 28 Report No. Operable Test (con’t) • In the operable test, the door is in working condition and must open and close • The resulting acoustic rating also highlights the loss of STC between the two tests. 4 The low frequency measurements of sound transmission loss can be affected by the test specimen size or the specimen edge restraints, or both, particularly for small modular specimens such as doors or windows. The presence of low-E or argon have negligible effect on sound attenuation characteristics. The STC (Sound Transmission Class) rating is a single-number rating system for interior building partitions and viewing windows used to The U. Oldcastle Glass has acknowledged OITC by providing charts which indicate the STC and OITC ratings of various glass assembly configurations. This The STC rating quantifies interior sound transmission while the OITC rating is recommended for exterior glass selection. This includes both STC and OITC ratings for steel and wood OITC* Frequency (Hz) 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 Transmission Class (OITC) rating describes its approximate decibel level reduction of sounds such as those of roadway and rail traffic, and of nearby aircraft takeoffs. The OITC rating is a single number rating calculated from the sound transmission loss values measured from an acoustic test. Consequently, the outdoor-indoor transmission class (OITC) can also be affected by these factors, resulting in some uncertainty of the field American Craftsman® Product Performance Sound Transmission Ratings. Both OITC and STC indicate a wall’s ability STC Ratings vs. Architectural Glass Projects. N/A. Others include the sound transmission class (STC) and the noise reduction coeffi cient (NRC). COMMONLY USED TERMS dB – Decibel – This is the unit of measurement used when measuring sound levels. For more information on the ratings provided, please see the definitions below. Acoustic joint tapes and caulking have been used to improve sound isolation since the early 1930s Acoustic Doors Inoperable Test vs. Outdoor/Indoor Transmission Class (OITC) is a newer rating system developed specifically for measuring sound transmission of low- and mid-frequency noises through exterior walls. Crystal Lake, IL. S. STC 43. When choosing building envelop designs, designing using the OITC rating The OITC rating represents transmission loss results from 80 to 4,000 Hz using a different mathematical equation than the STC rating. new way of measuring sound transmission, an OITC rating is the rating, and Table 3 shows an example worksheet for calculating OITC. Download. How to Read an OITC Rating Chart. Its original intent was to quantify interior building partitions, not exterior wall components. The first measure of acoustic performance is referred to as the Sound Transmission Class or STC. Others include the sound transmission class ( STC ) and the noise reduction coefficient ( NRC ). The STC rating has been in existence for many years and is based on speech sounds. Although very similar, the OITC rating system is aimed at lower frequencies, such as construction work, rumbling engines, low-flying planes, and car horns, and it utilizes a wider frequency How to calculate an STC or OITC rating; STC versus OITC. Actual performance in real-life applications will depend on the exact configuration and the framing system used. 24 Page 1 of 7 Due to continual product research and development, details listed are subject to change at any time Discusses the acoustical properties of glass, methods of rating, such as STC and OITC, applicable standards and the relationship between glass and other glazing components in determining an overall rating. Outside-Inside Transmission Class (OITC)—measures sound transmission of low- to mid-frequency noises through exterior Outdoor-Indoor Transmission Class (OITC) is a single-number rating system for acoustical performance, developed primarily for the typical exterior noise spectrum. The OITC (Outside-Inside Transmission Class) rating is used to classify An Outdoor-Indoor Transmission Class rating specifies noise transmission from outside to inside. Final file including Rw, OITC, STC, and DB value under different sound Frequencies. (4) The higher the level, the greater the product's ability to resist forced entry. What is an Outdoor Indoor Transmission Class (OITC) rating? An OITC rating is a single number rating calculated in accordance with standard ASTM E1332 using the [ss] [ss] [ss] [ss] wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi-wpi- of 80 to 4000 hertz. In general, test specimens with higher STC ratings will have better acoustical performance than those with lower ratings. It is called the outdoor-indoor transmission class (OITC). There is a significant amount of information about the acoustic performance of concrete assemblies that is publicly available. The OITC is calculated by subtracting the logarithmic summation of the transmission loss values from the logarithmic summation of the A-weighted transportation noise reference spectrum. OITC is one rating system available to help compare the acoustic performance of various wall systems. The ISO international rating (Rw) can also be calculated if requested in advance. This data is accurate as of October 2018. The impressive acoustic make-up of WFR2 is also matched with these features: [pdf]: STC 56 Wall Only. This is typically 1 to 5 STC points depending on the quality of the seal and threshold assembly. The target STC values were 45 ‐ 50 and for OITC the target values were 35 ‐ 40. WFR2-Standard Depth (STC 62) in STC 68 Wall. The OITC (Outdoor Indoor Transmission Class) rating was created to test exterior walls and their elements (windows and doors). The charts below show comparisons between various types of glass and insulated glass units and also between North America, a rating system was introduced in 1970 under ASTM E 413 “Classification for Rating Sound Insulation. The American Architectural Manufacturers Association and the American Society for Testing and Materials came up with sound ratings to standardize and determine the rating of sound transmission for building components, particularly window. 5 outdoor-indoor transmission class, OITC, of a build-ing façade or façade element, n—a single-number rating calculated in accordance with Classification E1332 using measured The OITC (Outside-Inside Transmlssion Class) rating is used to classify acoustic performance of glazing in exterior applications. 4. Glass size and glazing system will a ect STC rating. Similar to the STC test, a sound source generates sounds at predetermined frequencies and the receiver measures what it hears. Acoustic performance of a wall assembly can be affected by workmanship and attention to detail while constructing a wall. Two common ratings for windows and doors are the Sound Transmission Class (STC) and Outdoor-Indoor Transmission Class (OITC) Ratings. STC 68 Wall Only. This metric measures the sound levels for interior building partitions where the tested for their acoustic performance. STC ratings accurately reflect the performance of windows installed on the inside of buildings, whereas OITC ratings more accurately reflect the performance of windows installed on the outside. The chart below summarizes Halio’s STC and OITC ratings. This rating is most appropriate for comparing performance of interior partitions to be used between rooms where there is not strong low-frequency sound. 5” Acoustics Assembly Number: ISS-00 OITC: Rw: 1/4″ RAL-TL85-169: 31: 29: 32: 1/2″ Structural Charts. Like the STC rating System, OITC measures sound intensity loss in decibels. com. Composition I. been introduced. The STC rating for a six inch concrete sub-floor is 52-55. ] OITC is a very new rating in the world of acoustics and not all products carry an OITC rating, as they may predate that testing being more commonplace. Assembly Components Finish material 5/8” Gypsum Size 2 1/2” Steel Stud Spacing 16” oc Product AFB Thickness 1. This rating increases to STC 42-45 with steel studs. A good level of isolation for walls and ceilings is STC 50 plus. (OITC)" r atings are for individual units based on independent tests and represent entire unit. 15kHz and is used in Europe. G. Refers to a window manufactured by Soundproof Windows, Inc. Reality of Sound Transmission Class (STC). WFR2-Custom 6-inch Depth (STC 64) in STC 68 Wall. STC 43 Assembly Components Finish material 5/8” Gypsum Size 2 1/2” Steel Stud Spacing 16” oc Product AFB Thickness 1. NRC’s Laboratory Measurements of the Sound Insulation of Building Façade Elements3 has OITC and STC ratings for common walls,roofs and windows. While OITC is often a slightly more appropriate way to evaluate windows, it isn’t nearly as recognized as STC, nor has it (1) See size charts in this section for available sizes. Acoustic glass windows offer some of the highest STC and OITC ratings available and are an excellent choice if you require the utmost in sound insulation. In the US, it is widely used to rate interior partitions, ceilings, floors, doors, windows and exterior wall configurations. The performance data below applies to triple-insulating glass To maximize a metal building’s acoustical performance, the wall and/or roof panels should include at least one layer of faced metal building insulation and one layer of unfaced metal building Acoustical Guide – Determining Minimum STC Rating Figure 1. 24 Page 2 of 7 Due to continual product research and development, details listed are subject to change at any time All assemblies include component descriptions, STC, OITC, Rvalue, and Rainfall data (if available). This includes both STC and OITC ratings for steel and wood stud walls, considering both interior and exterior assemblies. Most of the time, an assembly’s OITC rating is lower than an STC rating. 17. The first column is the rating of the door panel only; tested in a static inoperable condition to determine the sound transmission through the door. 228. The sound transmission class is a single number rating providing a convenient way to describe the sound transmission loss (TL) values. As a result, it is not recommended for glass selection of exterior wall applications since the single-number rating It uses varying glass thicknesses and specialized lamination techniques to disrupt different sound frequencies. Total Thickness STC OITC 6mm (1/4”) 35 31 10mm (3/8”) 38 35 OITC is similar to STC, but is measured for exterior areas across a frequency range of 80 to 4000 hertz and is therefore more applicable for low frequency noises coming from urban environments, such as traffic or airport noise. J2247-13-303-11-R0 Insulation Included: OITC, or Outdoor/Indoor Transmission Class, is a rating system used to measure how well a building assembly, like a wall or window, reduces sound transmission from outside to inside, specifically focusing on lower frequencies. OITC* Frequency (Hz) 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 Additionally, OITC ratings are used to determine how capable products are for use in low frequency sensitive areas. 5 fi berglass insulation batts, ⁄8" None TL-92-618 38 5 designed to deliver noise control ⁄8" Glass fi ber TL-93-325 49 5 in metal stud How the OITC Rating is Measured. Class (or OITC) is a relatively. Although very similar, the OITC rating system is aimed at lower frequencies, such as construction work, rumbling engines, low-flying planes, and car horns, and it utilizes a wider frequency . STC ratings are available for most common assemblies as well as for windows and doors. WESTERN ELECTRO-ACOUSTIC LABORATORY (WEAL) 30 35 40 45 50 55 60 65 Single Number Ratings –OITC Intent: a single number rating to assess the isolation provided of Summary Chart Condition Wall Min STC Mullion Result Low (Office) STC 40 Exposed STC 35–40 Mid-level (Hotel) STC 52 Wrapped or trim 800. WFR2-Standard Depth (STC 56) in STC 56 Wall. The STC rating for a basic insulated 2×4 wall with a single layer of drywall on each side is 35-38. com www. RW is similar but covers 100Hz to 3. These frequencies have a wider range three different glass configurations. greenfiber. (3) Published performance data is for single unit only. A brief review of acoustic ratings. OITC = Outdoor/Indoor Transmission Class (ASTM E1332) Type STC OITC: Birkdale Hollow Core: 25 22: Birkdale Solid Core: 32 29: Birkdale 20 min. The OITC rating, established in the ‘90s, is newer to the industry and is often overlooked in favor of the STC rating. Alumicor. com Report Number 01-31783. Sound Transmission Class and Outdoor/Indoor Transmission Class ratings for Andersen® windows and patio doors are based on the entire window unit or patio door construction. When that is the case, the OITC correlates well with the noise reduction achieved. 14 - 10logΣ f10((L f - TL f + A f)/10) (dBA ACOUSTIC PERFORMANCE: STC - OITC September 2023 www. Mercyhealth Hospital & Physician Clinic. i AlumícorM BUILDING EXCELLENCE The OITC is the preferred method of comparison of façade elements including roofs for blockage of exterior sounds. 2. The STC (Sound Transmission Class) rating is a single-number rating system for interior building partitions and viewing windows used to categorize acoustic performance. info@greenfiber. TD-136 - Recycled Glass Use An explanation of Vitro Glass's use of recycled glass. A SPW using 1/4" laminated glass A SPW using 5/8" laminated glass All tests were performed by Western Electro-Acoustic Laboratory (WEAL), a fully accredited OITC is a very new rating in the world of acoustics and not all products carry an OITC rating, as they may predate that testing being more commonplace. . 03. Thickness STC* OITC* Double Std I. Data is based on testing ~36" x 84" glass to ASTM E413-87 in an acoustical wall. Understanding OITC. To achieve your acoustic goals without settling for more expensive solutions, ask for dual-pane windows with dissimilar glass. The document provides acoustic performance data tables for insulating glass, triple insulating glass, monolithic 3. The figures in Column 3 for theA-weighting adjustments are taken from ANSI S1. A higher sound transmission class rating indicates more effective sound insulation than a lower rating. *OITC is estimated based on this test. It provides an estimation of the performance of the wall or floor in certain common sound insulation conditions. The OITC rating is used to measure the sound transfer between outdoor and indoor spaces. Description. The sound ratings are calculated by two primary control systems: sound transmission class and they let pass through. com 5500 77 Center Dr. 6. TLs are measured at somewhat lower frequencies than in STC testing. For all of these acoustic ratings, the greater the rating, the better is its resistance to sound transmission. The charts include OITC: This is a much newer rating system developed specifically to measure the extent to which an exterior wall insulates against outdoor noises in the low- to midfrequency ranges: heavy traffic, airplanes, trains, etc. Presentation of Results The chart below indicates the STC rating of specially made acoustic doors using various applications of gasketing. Fire Rated: 32 29: Acoustic Ratings - Interior Doors: Stile and Rail Interior Doors MODA Interior Doors Molded Wood Composite Interior Doors Flush Wood Composite Interior Doors TRIA Interior Doors: Andersen provides ratings for windows and patio doors' sound transmission into the home. ” This rating system is the Sound Transmission Class, or STC classification system. pdf), Text File (. 01 ASTM E1332-90: Standard Classification for Rating Outdoor-Indoor Transmission Class Series Curtainwall ”x 7-3/4” (captured) Architectural Testing (ATI) 17406. The second column is the rating of the operable door STC OITC Test Date Test Number Operating Style Series Numbers Tested Size OA Glass 1 Glass 2 Acoustical Ratings - Trinsic I V300 updated 04. Data on acoustic performance of specifi c wall assemblies is available on page 2. Windows and doors can help block outside noises whether you live in the city or on a farm. 3 Acoustic Surfaces In order to foster a pleasing acoustical environment for patients/residents and staff, FGI 2014 sets minimum average room absorption coefficients – rather than specifying specific acoustical finishes Outdoor-Indoor Transmission Class (OITC) rating. frequencies used in STC ratings correlate in a general way with subjective impressions of sound transmissions for speech, radio, and television. When choosing building envelope designs, designing using the OITC rating The updated TMS 302 Sound Standard provides minimum requirements for rating masonry walls for sound transmission class (STC) and outdoor-indoor transmission class (OITC) based on calculation. Both OITC and STC indicate a wall’s ability to block the transmission of sound from one side of the wall to the other. Frequency (Hz) STC OITC 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 sound transmission loss (dB) 1-3/4" overall - 1/4" glass, 1/2" airspace, includes both STC and OITC ratings for steel and wood stud walls, considering both interior and exterior assemblies. 2 glass of 3 mm 19 mm [¾''] 29 24 I. J2247-13-303-11-R0 Insulation Included End Result: The test report will include the sound transmission loss values from 80 to 5000 Hertz, the STC rating and the OITC rating. oqjn ljy dossdhh iraghgq hbdait otgl zrn htnrlye bqq mxh mpg pjoe zbgl xozva astqnt