Low Frequency attenuators are available in three models for specific applications requiring increased 2nd & 3rd octave band noise reduction. Performance data is provided for four basic lengths - 36”, 60”, 84”, and 120”. Units are also offered in 48”, 72”, and 96” lengths.
Model ALHP: Low frequency unit providing excellent attenuation for system velocities in the range of
Model ALMHP: Provides high attenuation values along with a moderate pressure drop in systems operating at 250-750 FPM.
Model ALMP: Provides good attenuation values along with a moderate pressure drop for systems operating at
Model ALMLP: Provides a low pressure drop for systems operating at 750-1250 FPM.
Model ALLP: Provides an excellent pressure drop for systems operating at 1000-1500 FPM.
Special features of our Standard Attenuators are:
ASTM E-84 ratings for the acoustical fill are:
- Diffusion angle to improve pressure drop
- Bellmouth entrance to help minimize
- 22 gauge galvanized steel casings
- 24 gauge 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
- Flamespread 10
- Smoke Developed 10
Components are also available in stainless steel or aluminum construction.
Acoustical performance ratings are based on tests conducted by Intertek Testing Services, formerly ETL Testing Laboratories, Inc., Cortland, New York, 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.