Sonodec 160 mm 6 meter

Acoustically and thermally insulated ducting from DEC International, 160 mm bore and 6 metres long. A perforated aluminium laminate inner hose, a blanket of glass wool around it and an aluminium laminate outer sleeve.

What the manufacturer actually measured

With products like this, "quieter" is an easy promise. DEC has the attenuation of this ducting measured by the acoustics consultancy Peutz and publishes the results per size and per length, so you can work from a figure rather than a claim.

For the 160 mm these are the values, in decibels per frequency band:

• 1 metre: 17 dB at 125 Hz, 22 at 250, 22 at 500, 27 at 1000, 19 at 2000 and 14 at 4000 Hz
• 2 metres: 31, 39, 34, 38, 31 and 20 dB
• 3 metres: 29, 43, 41, 46, 39 and 27 dB

Two things stand out. Attenuation is strongest around 250 to 1000 Hz, which is exactly where the hum of an inline fan sits. And at 4000 Hz the values are much lower, meaning sharp hiss from moving air is not removed as well as the lower hum.

DEC measures up to 3 metres. This length is 6 metres, so you comfortably have the length at which the highest published figures were reached; beyond 3 metres the manufacturer publishes nothing and we do not fill that in ourselves.

Technical Specifications:

• Manufacturer: DEC International
• Build: perforated inner hose, closed barrier film, glass wool, aluminium laminate sleeve
• Glass wool blanket: 25 mm, 16 kg per m³
• R-value: 0.65 m² K/W
• Temperature: -30 to 140 °C
• Working pressure: maximum 2500 Pa
• Size: 160 mm
• Length: 6 metres

Frequently asked questions

Does 46 dB mean my fan becomes inaudible?
No. It is the attenuation this ducting adds in that frequency band, not the end result for your whole installation.

Why are the values lower at 4000 Hz?
That is simply how the material behaves. Most of the gain sits where a fan makes most of its noise.

Is 6 metres better than 3?
More length helps, but the manufacturer measures to 3 metres, so beyond that we quote no figures.