Compact sound attenuator for circular ducts

A rectangular sound attenuator with circular connection spigots. Unique properties regarding installation height, fire-resistance class, fibre-migration proof design and sound attenuation. Patent-pending self-supporting fibre-migration proof surface lining and end wall solution.

  • Extremely low installation height.
  • Very good sound attenuation
  • Fibre-migration proof
  • Air tightness class D
  • Low pressure drop
  • Included in the MagiCAD database
  • Fire-resistance class EI30 to EI120*
    *See the table for requisite safety distance

The new CLA is an industrially fabricated product designed for excellent sound attenuation and ease of installation. The standard CLA is made of galvanised sheet steel.

The connection spigots are fitted with rubber seal rings. Type-approved to Ductwork leakage class D

The fire-resistance class is met by providing adequate safety distance. Specified safety distance in the table refers to evacuating persons or 2.5 kW/m2.



The CLA-B is a rectangular sound attenuator for connection to circular ducts, is equipped with an acoustic centre baffle for improved sound attenuation data.

The installation height is as much as 80 mm lower than equivalent conventional sound attenuators.

The CLA-B is an excellent option, for kitchen flues for in- stance (held by means of a fixing clamp for simple removal for cleaning. The sound attenuator is also available in ver- sions without baffle and with smaller duct connection sizes. For more information, contact your nearest Swegon Office.

The sound-attenuating material on dimension 500-800 ISOVER Cleantec® PLUS, is a type-approved insulation material consisting of long-fibred compressed mineral wool. The mineral wool is covered with a micro-perforated aluminium foil. ISOVER Cleantec® PLUS is type-approved for cleaning using liquids with a plastic brush or even a high- pressure cleaning apparatus. Naturally it also conforms to relevant standards regarding cleaning, fibre entrainment, resistance to ageing and emissions, etc. to type-approval number 2706/92.

The connection spigots are fitted with rubber seal rings. The standard CLA-B is made of galvanised sheet steel.

กำลังมองหาระบบระบายอากาศ ERV สำหรับที่พักอาศัยอยู่ใช่ไหม?

เพื่อสร้างคุณภาพอากาศที่เหมาะสมที่สุด เราออกแบบโซลูชันการระบายอากาศ ERV ให้เหมาะกับแต่ละบุคคล กรอกแบบฟอร์มเพื่อรับคำแนะนำจากฝ่ายวิศวกร-ฝ่ายขายของเรา
We create Europeean Standard ERV Solutions Fill in the form to get personal guidance

Looking for ERV Residential Ventilation?

Creating the optimal solution for you requires knowledge of your specific situation. 

Book a free guidance call below