The 'C1..QS' (Q-seal) circular attenuators are one diameter long. They have an impervious seal between the acoustic fill and ambient air. They are used in critical applications where the possibility of fibre contamination of the acoustic fill is not allowed. There is a penalty on the acoustic performance in exchange for the certainty that fibre fly is eliminated. Typical applications are as follows: -

• clean rooms
  
• operating theatres
  
• wet environments where attenuators are exposed to the elements
  
• kitchen exhaust systems
  
• applications where workers are sensitive to fibre exposure

Model	Diameter	External Diameter	Length	dB(A) Reduction
C1-031QS	315	481	300	6
C1-035QS	350	521	300	6
C1-040QS	400	566	600	6
C1-045QS	450	616	600	6
C1-050QS	500	666	600	6
C1-056QS	560	730	600	6
C1-063QS	630	800	600	6
C1-071QS	710	880	900	6
C1-080QS	800	970	900	6
C1-090QS	900	1070	1150	6
C1-100QS	1000	1220	1150	6
C1-125QS	1250	1470	1150	6
C1-140QS	1400	1620	1150	6
C1-160QS	1600	1820	1800	6
C1-180QS	1800	2020	1800	5
C1-200QS	2000	2220	1800	5

The 'C2..QS' (Q-Seal) circular attenuators are nominally two diameters long. They have an impervious seal between the acoustic fill and ambient air. They are used in critical applications where the possibility of fibre contamination of the acoustic fill is not allowed. There is a penalty on the acoustic performance in exchange for the certainty that fibre fly is eliminated. Typical applications are as follows: -

• clean rooms
  
• operating theatres
  
• wet environments where attenuators are exposed to the elements
  
• kitchen exhaust systems
  
• applications where workers are sensitive to fibre exposure

Model	Diameter	External Diameter	Length	dB(A) Reduction
C2-031QS	315	481	600	11
C2-035QS	350	521	600	11
C2-040QS	400	566	900	11
C2-045QS	450	616	900	11
C2-050QS	500	666	1150	11
C2-056QS	560	730	1150	11
C2-063QS	630	800	1150	12
C2-071QS	710	880	1500	12
C2-080QS	800	970	1500	12
C2-090QS	900	1070	1800	11
C2-100QS	1000	1220	1800	11
C2-125QS	1250	1470	2400	11
C2-140QS	1400	1620	2400	10
C2-160QS	1600	1820	3600	10
C2-180QS	1800	2020	3600	9
C2-200QS	2000	2220	3600	9