Sound Attenuator Supply Air Tubing R4 Insulation - 12ft (6pcs)

Sound Attenuator Supply Air Tubing R4 Insulation - 12ft (6pcs)

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Availability: In stock

Model #: UPC-26CR4-6
Brand : Unico

Availability: In stock

  • Unico Small Duct System

  • Flexible Air Duct

  • R4 Insulation

  • 6 Pieces

  • 2" x 12'

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Unico Sound Attenuator Supply Air Tubing R4 Insulation - 12ft (6pcs) - UPC-26CR4-6


The Unico System sound attenuator tubing is a 2-inch Flexible Air Duct designed to reduce the high velocity air noise to a whisper. It also provides an insulated vapor barrier to prevent condensation from forming on the outside of the duct. For a properly designed Unico System it is essential to use the sound attenuator at the end of every branch duct to prevent unwanted noise.

The Sound Attenuator is offered with several different choices of insulation thickness. In most cases, the standard sound attenuator should be used. However, for extremely cold or humid environments or where the local building code requires a specific R-factor and the duct is installed in an unconditioned space, use the R4, R6, or R8 products. The R4, R6, and R8 ducts have thicker and heavier insulation than the standard sound attenuator to reduce thermal losses.


The sound attenuator significantly reduces sound from the outlets. Therefore, it is essential for proper noise control to use at least 3 feet of the sound attenuator at the end of every two-inch branch run (Method B). Alternately, for convenience or better sound attenuation, the entire branch duct can be made of one or more lengths of sound attenuator (Method A). However, because the aluminum core tubing is stronger than the sound core, for lengths greater than 12-feet it is best to use almost all UPC-25 aluminum supply tubing with a 3- foot length of sound attenuator at the end (Method B).

Where runs are required to be installed in unconditioned spaces every attempt should be made to limit the length of the duct run to 12-feet or less using the proper R-factor for the application. However, as an air duct, there is no limit to the length used other than its ability to deliver the air.


The sound attenuator tubing has a 2-inch inside diameter supplied in 12-foot lengths and can be cut as needed. The standard sound attenuator (UPC-26C) is made of three layers. These layers combined have an R factor of 3.2 °F-hr-ft2/Btu.

The inner layer/core consists of a double layer of spunbonded nylon filter material, which is reinforced with a helical wire. The nylon cloth is porous to air but will not allow fiberglass particles to pass through it. The outer jacket is made of two-ply reinforced reflective mylar; providing a vapor seal to prevent leakage and moisture migration, and increases the insulation factor by reducing the radiant heat transfer. Fiberglass blanket insulation fills the void between the jacket and the nylon core.

The standard duct has one insulation layer 0.75 inch thick; the R4 duct insulation layer is 1.0 inch. The R6 and R8 duct both have two layers of insulation and a double vapor seal; The R6 total insulation thickness is 1.5 inches and R8 total insulation thickness is 2.0 inches.

Additional Information

Brand Unico
Application No
liquid_line_connection_size No
Suction Line Connection Size No
amperage(amp0 No
Heating Capacity No
Cooling Capacity No
Warranty No