RUSKIN Sound Control
3900 Dr. Greaves Road
Grandview, Missouri 64030
Phone	816.761.7476
Fax	816.763.0986

SECTION 15820

DUCT SOUND ATTENUATORS
MODELS CNB, CNC

PART 1		GENERAL

1.1	SECTION INCLUDES

A.	Galvanized steel duct sound attenuators

1.2	REFERENCES

A.	ASTM E477 - American Society for Testing and Materials, Standard method of testing duct liner material and prefabricated silencers for acoustical and airflow performance.

B.	NFPA 255 - National Fire Protection Association, testing of air conditioning and ventilation systems

C.	ASTM E84 - American Society for Testing and Materials, testing of air conditioning and ventilation systems

D.	UL-723 - Underwriters Laboratories, standard for safety; duct silencers

1.3	SUBMITTALS

A.	Comply with requirements of Section 01330 - Submittal Procedures

B.	Product Data: Submit manufacturer’s product data.
1.	Include dynamic insertion loss data.

2.	Include pressure drop data.

3.	Verify conformance of ASTM E477, ASTM E84, NFPA 255, UL-723, and applicable building codes

4.	Verify silencer dynamic insertion loss and pressure drop ratings based on tests performed at independent lab testing facility.

1.4	QUALITY ASSURANCE

A.	Dynamic Insertion Loss: Silencer dynamic insertion loss based on tests and procedures performed in accordance with ASTM E477 testing procedures at nationally recognized independent laboratory.

B.	Pressure Drop:  Silencer pressure drop performance based on tests and procedures performed in accordance with ASTM E477 testing procedures at nationally recognized independent laboratory.

1.5	DELIVERY, STORAGE, AND HANDLING

A.	Delivery:  Deliver materials to site in manufacturer’s original, unopened containers and packaging, with labels clearly indicating manufacturer and material.

B.	Storage:  Store materials in a dry area indoors, protected from damage and in accordance with manufacturer’s instructions

C.	Handling:  Handle and lift silencers in accordance with manufacturer’s instructions.  Protect materials and finishes during handling and installation to prevent damage.

PART 2		PRODUCTS

2.1	MANUFACTURER

A.	RUSKIN Sound Control, 3900 Dr. Greaves Road, Grandview, Missouri 64030.  Phone: 816.761.7476.  Fax: 816.763.0986.

2.2	DUCT SILENCER MODELS CNB, CNC

A.	Fabrication:
1.	Model:  Tubular silencer, models CNB, CNC.

2.	Outer Casing:  22 gauge G90 galvanized (suitable for outdoor use) outer casing.

3.	Internal Liner: 22 gauge G90 galvanized (suitable for outdoor use) internal liner.  Liner shall be perforated steel and shall be acoustically transparent.

4.	Baffle Fill:  Inorganic glass fiber acoustic material fill.  Glass fiber packed under 5% compression to eliminate voids due to settling.

5.	Pod Construction:  Pods constructed as full length center bullet within silencer.  Pod attached to silencer body in radial fashion with 4 supports, 90 degrees apart to insure stability.

6.	Flange:  Body shall extend for 1 ½” flange past silencer.  This allows for ease of installation, flange shall be solid or bored with bolt holes at factory.

7.	Construction:  Silencer constructed using Pittsburgh Lock Seam sheet metal construction.  Sound attenuators capable of withstanding a differential air pressure of 8” w.g.  Airtight construction shall be provided by use of a duct sealing compound on the job site, contractor shall supply material and labor.

8.	Assembly:  Factory shall assemble silencer and accessories and furnish as a single unit. 

B.	Performance Data:
1.	Based on testing 24 inch diameter sample (length 2x diameter). 

2.	Maximum recommended Air Flow - Model CNB - 6000 fpm, Model CNC - 6000 fpm.

3.	All acoustical performance data is derived from independent laboratory testing in accordance with ASTM E477 testing procedure.  Testing executed in a duct-to-reverberant room laboratory, providing for airflow in both directions through the silencer.  Dynamic Insertion Loss (D.I.L) calculated for: 
Forward Flow - air and sound move in same direction.
Reverse Flow - air and sound move in opposite directions.

4.	Aerodynamic performance data is derived from independent laboratory testing in accordance with ASTM E477 testing procedure.  Data shall be presented for the same units as those tested to ascertain acoustical performance data.

5.	Fire and smoke performance data derived from testing in accordance with ASTM E84, NFPA 255, and UL-723 testing methods.  Incombustible filler material exhibits the following fire hazard classification values:
FLAMESPREAD	-	20
FUEL CONTRIBUTED	-	15
SMOKE DEVELOPED	-	20

2.3	ACCESSORIES

A.	Mylar Lining:  Acoustic fill lined with mylar to prevent erosion of acoustic fill and/or absorption of moisture by insulation. Bacterial or microbial growth within silencer is also reduced. 

B.	Tedlar Lining:  Similar to mylar lining but with additional chemical protection.  Suitable for outdoor use.

C.	Fiberglass Cloth Lining:  Prevents erosion of acoustic fill into airstream.  Fiberglass lining has the added advantage of being acoustically transparent, not affecting silencer acoustical performance.

D.	Capped Ends:  Silencers can be manufactured with capped ends to prevent contamination during delivery to job site and at job site.

E.	HTL Casing:  Silencer can be equipped with STC 45 High Transmission Loss casing to prevent breakout noise through side walls of unit.
 
PART 3		EXECUTION

3.1	EXAMINATION

A.	Inspect areas to receive sound attenuators.  Notify the Engineer of conditions that would adversely affect the installation or subsequent utilization of the silencers.  Do not proceed with installation until unsatisfactory conditions are corrected.

3.2	INSTALLATION

A.	Install sound attenuators at locations indicated on the drawings and in accordance with manufacturer’s installation instructions.

B.	If duct transitions are required to adapt silencer dimensions to installed ductwork dimensions, the contractor shall provide the required hardware and labor.