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Circular EPDM flexible connections - Model 521 and 522 industrial grade, all welded construction - dB Noise Reduction



  • Fan inlets and outlets
  • Pressure blower inlets and outlets
  • Compressor inlets and outlets
  • Scrubber inlets and outlets
  • Stack inlets
  • Ventilation and process ductwork

Model 521 circular EPDM
flexible connections

  • Tough, 1/8" thick, layered EPDM flex membrane with internal nylon scrim for superior tear strength
  • Resistance to ozone and UV exposure, and cold cracking makes it ideal for outdoor use
  • Good for airstream flows to 6,000 fpm and pressures from -30" wg to +120" wg
  • All welded, matched and drilled flanges
  • Backing bars fastened in place with zinc plated hardware

Model 522 circular EPDM
flexible connections

  • Identical construction to Model 521 flexible connections, with an aerodynamically designed, protective metal flow liner
  • Good for airstream flows over 6,000 fpm and pressures from -120" wg to +120" wg (with a flow liner)
  • Double deflectors are also available for extra flow protection and noise reduction
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Circular EPDM flexible connections

Circular EPDM flexible connections - features - dB Noise Reduction   Circular EPDM flexible connections - detail - dB Noise Reduction

Circular EPDM flexible connections features - dB Noise Reduction

Product details

Operating temperatures:

Up to 225° F


Up to 6,000 fpm (Model 521)
Over 6,000 fpm (Model 522)


-30" wg to +120" wg (Model 521)
-120" wg to +120" wg (Model 522)


From 12" ID to 120" ID (standard)
Larger sizes available

Flange-to-flange length:

8" for flanges less than 4"
10" for flanges 4" and larger

Lateral and axial movement:

+/- 0.5"

Unit weight:

Up to 600 lbs (standard sizes)


Carbon steel flanges, backing bars and flow liner
(if supplied), zinc plated backing bar hardware
and EPDM flex membrane

Stainless steel flanges, backing bars, flow liners
and hardware available

Galvanized construction also available

Paint finishes:

Alkyd, enamel, high heat, inorganic zinc, epoxy
and polyurethane

For other customized flexible connection designs, please contact us and we will be happy to assist you.


Servicing clients in the US, Canada, Mexico, and many international locations worldwide.