Acoustical Flexible Ducts (DB-series)
Clevaflex’s DB-Series Acoustical Flexible Ducts are manufactured to provide the highest sound dampening and attenuation possible for straight- and bent-duct applications.
| DB Core | Type DB | Type DBA | |
|---|---|---|---|
| Construction: | One ply of perforated and corrugated aluminum with interlocked seams, folded flat and knurled for flexibility and strength. | DB core wrapped with fiberglass insulation and sleeved in a polyethylene vapor barrier. | DB core wrapped with fiberglass insulation and sleeved in a fiberglass reinforced, metalized polyester vapor barrier. |
| Length: | 10’ standard | 10’ standard | 10’ standard |
| Operating Temp: | 0 - 750°F | 10 - 200°F | 10 - 200°F |
| Velocity: | 3,000 FPM | 3,000 FPM | 3,000 FPM |
| Working Pressure: | 2” WC positive and negative | 2” WC positive and negative | 2” WC positive and negative |
| Burst Pressure: | 4” WC | 4” WC | 4” WC |
| 1-Ply Aluminum Core: | .0055” thick, AL 3003-H111 | .0055” thick, AL 3003-H111 | .0055” thick, AL 3003-H111 |
| Insulation: | N/A | 1-1/4” thick Std. | 1-1/4” thick Std. |
| R-Value: | N/A | 4.2 Std., 6.0 & 8.0 | 4.2 Std., 6.0 & 8.0 |
| Vapor Barrier: | N/A | 0.17 perms | 0.05 perms |
| ID Size | 3" | 4" | 5" | 6" | 7" | 8" | 9" | 10" | 12" | 14" | 16" | 18" |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Weight oz/ft: Type DB, DBA | 3.4 | 4 | 4.8 | 5.9 | 6.6 | 7.8 | 9.4 | 11.3 | 13 | 15 | 17.2 | 19.4 |
| Crush Strength - lbs/ft | 50 | 50 | 50 | 45 | 45 | 40 | 40 | 35 | 35 | 35 | 35 | 35 |
| Span - Max Unsupported | 6' | 8' | 10' | 10' | 10' | 10' | 10' | 10' | 10' | 10' | 10' | 10' |
Note: ID sizes are nominal and weights approximate
Type DB Core
Type DB
Type DBA
Codes:
- Clevaflex Type DB and Type DBA have been tested by Underwriters’ Laboratories to UL Standard 181 and are listed as Flexible Air Duct Connectors, Class 0 and Class1.
- Clevaflex Type DB and Type DBA meet the requirements of Bulletin 90A of the National Fire Protection Association for all diameters.
Type DB and Type DBA
Sound Attenuation With and Without Airflow:
Straight Flexible Duct – Insertion Loss (IL) in dB per foot
| Octave Band Number | -2 | -3 | -4 | -5 | -6 | -7 | -8 | |
|---|---|---|---|---|---|---|---|---|
| Center Frequency - Hz | 125 | 250 | 500 | 1,000 | 2,000 | 4,000 | 8,000 | |
| IL @ Zero FPM | 6" ID Duct | 2.9 | 2.9 | 3.2 | 3.4 | 3.5 | 3.6 | 2.3 |
| 12" ID Duct | 2.7 | 2.7 | 2.3 | 2.8 | 3.2 | 2.5 | 1.5 | |
| 16" ID Duct | 2.3 | 2.5 | 2 | 2.6 | 3 | 2 | 1.4 | |
| IL @ 2,500 FPM | 6" ID Duct | 2.8 | 3 | 3.4 | 3.4 | 3.3 | 3.3 | 2 |
| 12" ID Duct | 2.6 | 2.8 | 2.5 | 3 | 3.3 | 2.4 | 1.3 | |
| 16" ID Duct | 2.3 | 2.5 | 2.2 | 2.8 | 3 | 2.1 | 1.2 |
Flexible Duct with 90-degree Bends – Insertion Loss (IL) in dB per foot
| Octave Band Number | -2 | -3 | -4 | -5 | -6 | -7 | -8 | |
|---|---|---|---|---|---|---|---|---|
| Center Frequency - Hz | 125 | 250 | 500 | 1,000 | 2,000 | 4,000 | 8,000 | |
| IL @ Zero FPM | 6" ID Duct | 2.4 | 2.7 | 3.3 | 3.7 | 3.6 | 3.6 | 2.5 |
| 12" ID Duct | 2.4 | 2.6 | 3 | 3.1 | 3.1 | 2.6 | 1.3 | |
| 16" ID Duct | 2.4 | 2.4 | 2.4 | 2.4 | 2.5 | 2.2 | 1.1 | |
| IL @ 2,500 FPM | 6" ID Duct | 2.2 | 2.9 | 3.5 | 3.6 | 3.3 | 2.8 | 2.1 |
| 12" ID Duct | 2.2 | 2.6 | 2.9 | 3 | 2.8 | 2.3 | 1.2 | |
| 16" ID Duct | 2.1 | 2.5 | 2.3 | 2.3 | 2.2 | 1.9 | 1.1 |
Air Diffusion Council Test:
Clevaform Type DB has been tested in accordance with the Air Diffusion Council Flexible Air Duct Code FD 72. Data presented in the charts above depicts the attenuating quality of the product. The test(s) were conducted using the net insertion loss method and reflect the difference between values for empty metal duct and the test specimen.
Test Procedure:
A 10-foot long smooth, straight, empty metal duct section is installed in a duct system. Test signals are generated at one end of the duct and then measured in a reverberation room at the other end. The empty metal duct is removed and replaced with Clevaform Type DB and the test is repeated. These procedures are followed for different airflows, as well as straight and 90-degree bends.
Suggested Specification(s):
- Contractor shall furnish and install Clevaform DB-Series Acoustical Duct Types DB or DBA as manufactured by Clevaflex in sizes and locations where indicated on drawings.
- Clevaform Type DB and DBA core shall be all-metal, semi-rigid construction, consisting of a single ply of perforated and corrugated aluminum, with seams interlocked, folded flat and knurled for strength and flexibility.
- Clevaform Type DB shall be wrapped with fiberglass insulation and sleeved in a polyethylene vapor barrier.
- Clevaform Type DBA shall be wrapped with fiberglass insulation and sleeved in a fiberglass reinforced, metalized polyester vapor barrier.
- Duct connections to equipment and outlet collars shall be made in accordance with the manufacturer’s recommendations.
Note 1: Since installation of the materials and conditions of use are important factors in obtaining satisfactory results and are beyond our control, Clevaflex can make no warranties, expressed or implied, including warranties of merchantability and fitness for a particular purpose, with respect to the material or its use or performance. All consequential damages whatsoever are expressly excluded.
Note 2: The statements regarding the characteristics, properties and performance of the materials described herein are based on data believed reliable, but no guarantee of their accuracy is made and such statements should not be construed as warranties or as the basis therefore.