Sound attenuators permit the passage of air while reducing noise in ventilation systems. Attenuation certification for this series of attenuators is. The combined interior diffuser cone and exterior square jacket casing make these units into aerodynamic regain devices as well as silencers. Page 3 of 12 a digital attenuators frequency range should be matched to the application of interest. Supply and sound attenuator duct model key available models wh general the aluminum supply tubing and sound attenuator are insulated flexible air ducts. Series 081 model 2608106 features full waveguide band low frequency sensitivity the fixed attenuators, series 081, are low vswr devices suitable for operating over the full waveguide band. Fixed fiber optic attenuator, also called fixed plug type or fixed buildout fiber attenuator, is used in fiber optic communications to reduce the optical fiber power by a certain level. The iac type lfs quietduct silencers provide superior low frequency attenuation. Iac is the only company in the world that manufactures and sells cleanflow attenuators. Iac acoustics designs d duct diffuser silencers dds for installation at the outlet of vane axial fans. Sa sa sas r ca cb rectangular circularand used for smaterials sound attenuator. Quiet duct ultra green silencers offer 100% environmentally friendly attenuation solutions. In the lower frequencies, such as 125 hz, even greater lengths of duct lining would be required to achieve the 10 20 db insertion loss typically achievable by many of the broad range of iac silencers including the lfs series.
The light weight, low profile construction also provides corrosion resistance over metal silencers. Attenuators weaken or attenuate the high level output of a signal generator, for example, to provide a lower level signal for something like the antenna input of a sensitive radio receiver. Airflow in the silencer is in the opposite direction to the noise propagation. Silencer information and definitions enoisecontrol. Triple lock sound attenuator sa the metal core is constructed from perforated and corrugated dead soft aluminum with mechanical interlocking seams the fiberglass insulation is used between the core and outer shell the outer shell is constructed from dead soft aluminum that is corrugated with mechanical interlocking seams to form an air tight, flexible, metal duct. Any specification change must be submitted in writing and approved by the architectengineer, in. Welcome to hasco components precision rf and microwave coaxial attenuator section. Rf coaxial attenuators are used for test and measurement applications. Performance data is provided for eight centerline lengths 36, 48, 60, 72, 84, 96, 108, and 120.
Silencers can be fitted to the inlet outlet of circular duct fans or to grilles and louvres as required. If the duct is located inside the conditioned building envelope, use the standard insulation which is. Refer to the rtqs series for applications where moisture may be present in the air stream. Noise generated in the silencer and caused by the gas interaction with the silencer. The iac acoustics quietduct silencers meet stringent design requirements from acoustical consultants, consulting engineers, owners and contractors. It is convenient to discuss them along with decibels. To satisfactorily select an attenuator the following information is required. Ac sound attenuator are used in air conditioning system to mitigate excess sound generated by air handling units and air conveying ducts. Iac acoustics rectangular and cylindrical duct attenuators provide effective, predictable noise reduction at substantial savings over other noise reduction. The sound attenuators should have adequate silencing capabilities, low air resistance and be as small as possible. The attenuation from the terminal to the room is 5 db. Standard models are available in a range of attenuation values from 3 db to 30 db.
Insertion loss is considered part of the fixed performance of the system path in which the step or variable attenuator is located. Section 01 33 23 shop drawings, product data, and samples c. Duct attenuator acoustic attenuator ventilation airmatic. Rectangular silencers are intended for silencing noise in rectangular ductwork and a wide range of design options allow them to be integrated into any hvac system with ease.
Cross talk attenuator introduction cross talk silencers are designed to maintain sound transmission ratings in low velocity air transfer between adjoining spaces. Ct2 uses a resistor network built on noninductive smd resistors. Fixed attenuators in circuits are used to lower voltage, dissipate power, and. Circular attenuators greenmill ac stocks a range of circular silencers for your current air conditioning or ventilation project. For high insertion loss with broadband damping, even in the highfrequency range. Attenuators reduces the amplitude or power of a signal without distorting its waveform. Extreme linearity of fets used in super rf cmos attenuator results its being. Attenuation due to end reflection is entered below.
The silencers may be bent to a maximum radius of 2 x overall. Danish audio connect manufactures a range of highend stepped audio attenuators for hifi, av and proaudio, used by diy audiophiles and audio equipment manufacturers throughout the world. Single duct attenuator dimensional data ezta units with integral sound attenuator ezta units notes. The iac aeroacoustic laboratory begins offering thirdparty testing services. Calculate the attenuation in unlined and lined ducts. Attenuators amplifiers and active devices electronics. Circular duct attenuators specialist ventilation services. The attenuator series, model 777c for example, is avail able in eight standard attenuation values from 3 to 60 db and is calibrated at dc, 4, 8, 10 and 12. The ventaxia rigid duct attenuator is suitable for residential and commercial applications including schools and offices. It is only in larger ducts and at higher frequencies the attenuation is considerable. Lfs silencers are advantageous where low frequency dil requirements are high in hvac systems. Typical attenuation values are between 1 and 30 db. Furnish and install quiet duct elbow style silencers of the types and sizes shown on the plans andor listed.
In ventilation systems, noise stems from a variety of components such as the fans or the fire dampers. Manufactured in galvanised sheet metal with 50mm rockwool sound absorption material. Metal forms sound attenuators are manufactured in many varieties, module sizes and materials, designed to eliminate acoustical fill entrainment. Duct attenuator solutions are available in standard sizes and models, and we can help advise which range is right for your needs. Moreover, we manufacture duct silencers to specific metal tolerances with controlled acoustic infill flow resistances to achieve consistent results. This includes noise on the inside of buildings and noise radiating outside to the surrounding neighbours.
Ncs acoustics design, manufacture and install many types of attenuators, including. Sda small duct attenuators attenuato r typical standard size range model applications width height length sda crosstalk, terminal or duct 150 450mm 150 450mm 600 1800mm mounted attenuation in 50mm increments in 50mm increments in 300mm increments mda duct or equipment 300 2400mm 300,450,600,750,900,1050, 600 2400mm. Quietduct silencers iac acoustics pdf catalogs technical. Corporate buildings, industrial, commercial offices material. Sound power and sound pressure are different in that sound power is a measure of. Dvac sound attenuators are designed to achieve the required performances as set out in the astm standards e47706a for prefabricated attenuators. Fixed attenuators in circuits are used to lower voltage, dissipate power, and to improve impedance matching. Single duct attenuator ezta units with integral sound. From building services hvac systems to industrial discharge stacks, duct attenuators control noise. The design of the cleanflow quiet duct silencers is suitable for air handling systems requiring the ultimate in cleanliness and hygiene. Iac packless silencers are reactive attenuators with no acoustic infill or lining materials. Please contact to our sales for other customized values.
Digital step attenuators offer precision and linearity. It comes in two sizes and four different insulation thicknesses. Sound power level attenuation in an elbow is caused by sound reflection. Attenuation in lined and unlined ducts at different sizes and frequencies are indicated in the table below. The choice of attenuators below are all 600mm long, with diameters of 100mm, 125mm, 150mm, 200mm, 250mm, 300mm and 400mm.
Iac has been manufacturing quiet duct attenuators for over 50 years, installing thousands of units each year. Iac acoustics quiet duct silencers acoustical solutions. To comply with a specified noise level, sound attenuators are added to suitable locations in the ventilation system. Lfs series lightweight flexible silencers pacific ventilation.
Single duct air terminals b model ezta single duct attenuator dimensional data ezta units with integral sound attenuator ezta units notes. Consult iac acousticss entire quietduct silencers catalogue on medicalexpo. Easily installed, the duct attenuator is used in the system to absorb sound. Model 2608106 fixed attenuator other attenuation values are available to order series 081 for standard flange types and rec om men da tions see pages 118 onwards standard attenuation values suf. Maximum insertion loss l balanced performance m ultralow pressure drop h construction type. Elbow attenuators are available in three models for horizontal or vertical applications requiring broad band noise reduction when space for straight attenuators is not available. Duct silencers acoustic louvers oneill engineered systems.
Hasco stocks an extensive selection of rf and microwave attenuators. The absolute attenuation is within 10% of nominal value. Cda circular duct attenuators uk cda2 1 of 2 caice internal diameter external diameter pod o d length octave band static insertion lossdb weight kg e d rn gd etail s 63 125 250 500 1k 2k 4k 8k n d p. Weights are approximate and will vary based on selected options, insulation type, etc. Offering excellent sound reduction over a range of frequencies, the rigid duct attenuator is available in two lengths depending on the noise suppression requirements. Thank you for your enquiry, someone will be in touch soon. Iac has been manufacturing cleanflow attenuators for many years, installing hundreds of units each year.
When low frequencies are controlling, a type lfs selection often results in. Triple lock sound attenuator product sheet testing was provided by intertek laboratories. Acoustic attenuator insertion loss data for the attenuators to be derived from tests in accordance to bs4718. Model 779 is available in 15 standard attenuation values from 1 to 60 db and is calibrated at dc, 4, 8, 12.
The sound wave generated by these sources transfer its energy throughout the duct and to the occupants area as shown below. Air duct silencers and acoustic louvers are commonly used at the intake and exhaust openings to reduce noise to an acceptable level. The acoustic baffles provide excellent attenuation of speech and unwanted noise while permitting fresh air to circulate continuously. Industrial air duct silencers for hvac noise enoise control. Quietduct commercial series silencers iac acoustics. Rectangular and circular duct silencers, as well as acoustic louvers, control the noise generated by air moving equipment. Noise control measures, such as silencers, allow the air to flow freely from the necessary generators without the addition of any unwanted sound. Sound attenuator without data airmaster equipments emirates.
Rectangular silencers noise control price industries. Rtqs series rectangular qseal attenuators the rectangular qseal attenuator includes the qualities of the rt series attenuator and incorporates an infill system fully. Rotary are madebeforebreak the available values are 10k, 50k, 100k, and 250k ohms. We have standard sizes readily available and are also manufacture to individual requirements. In some systems high frequency attenuation may be provided. They do their job by utilizing acoustical baffles as means for broadband sound attenuation in hvac systems. Testing was conducted in accordance with astm standard e4772006a, entitled standard test method for measuring acoustical and airflow performance of duct liner materials and prefabricated silencers and adc test code fd 72r1, entitled flexible air. The product suitable for residential and commercial applications including schools and offices, the ventaxia rigid duct attenuator has been developed as a cost effective and compact way of reducing noise within a ventilation system. Sound attenuation in duct elbows engineering toolbox. A wide variety of sound attenuator ducting options are available to you, such as hvac systems, air conditioning. Rectangular attenuators shall be of the rt, r3t or rtqs series as designed and manufactured by fantech pty. Available in 100, 125, 150, 200, 250, 315 and 400mm diameter sizes. Products components assemblies imas introduction attenuators.