Low Frequency attenuators are available in differant models for specific applications requiring increased 2nd & 3rd octave band noise reduction. Performance data is provided for four basic lengths – 3’, 5’, 7’, and 10’. Units are also offered in 4’, 6’, and 8’ lengths.
Model HP-LF is a high pressure drop unit ideally suited for system velocities below 1,000 fpm.
Model SP-LF also provides excellent low frequency attenuation values along with a standard pressure drop at somewhat higher air velocities.
Model LP-LF offers a lower pressure drop for higher velocity systems.
Special features of our Low Frequency Attenuators are:
- Diffusion angle to improve pressure drop
- Bellmouth entrance to help minimize turbulence
- 22 gauge minimum galvanized steel casings
- 24 gauge minimum perforated galvanized baffles
- Long strand Fiberglass acoustical fill
- Seams are mastic filled to insure airtight units to 8” w.g.
- Optional polyethylene, Mylar or fiberglass cloth liners A
- Also available in stainless steel or aluminum construction.
ASTM E-84 ratings for the acoustical fill are:
• Flame spread 10
• Smoke Developed 0
• Fuel Contribution 0
Performance Data / Testing
Acoustical performance ratings are based on tests conducted by Intertek Testing Services, formerly ETL Testing Laboratories, Inc.,
in accordance with ASTM E477 “Standard Method of Testing Duct Liner Materials and Prefabricated Silencers for Acoustical and Airflow
Performance.” Copies of the test reports are available upon request.