Specifications for:

Alfa 2M
Sound Insulating and Sound Absorbing Wooden Barrier A4/B3 Categories


 1.1. Wooden Panels

Soundproof and sound absorbing panels with high sound absorbing power made with first quality resinous wood compliant with UNI EN 350/1 regulation. The wood is treated in autoclave vacuum under pressure per DIN 68800 part 3 regulation.
The supporting frame is made of a box-shaped solid wood with minimum cross-section of 100×80 mm; the panels are jointed together to improve stability.
Inside the frame shall be placed the sound-absorbing material made of an underlayment of mineral wool with fiberglass 80 mm. thick and 100 Kg/m3 density.
This material shall not decay, shall not be reactive to chemicals, not affected by weather exposure, shall be fire proof or self-extinguishing, and shall not emit harmful toxic gas.
The material shall be placed at a distance from the panels using wood spacers in order to create a resonant chamber.
The side towards the noise source shall be made of a polythene silicon sheet of green color (or another upon request), fine weft 90%, weather and UV rays resistant, attached to the panel’s frame.
The face towards the noise source shall be finished with wooden slats autoclave treated nailed or screwed in, rounded and with minimum dimension of 50×20 mm. placed according to the configuration selected (horizontal, vertical, or at an angle). They shall be used as protection for the sound absorbing material, to break down the sound waves and also as decoration.
The back face of the panel, which is the sound insulating part of the barrier, shall be made of jointed wood boards with minimum thickness of 20 mm. and attached to the box-shaped frame by stainless steel nails.
To ensure traffic safety in case of fire, the panels (though flammable) shall be fire resistant (Class 1 flammability rating required).

Maintenance Treatment 
The wood shall be resistant to decay and to the UV sun rays aging effects, therefore it shall be treated with specialty products in accordance to regulations DIN 68800 and UNI EN 350-1-2 to prevent fungi growth.
The wood shall be treated with inorganic salts.
Firstly it shall be treated with deep autoclave vacuum under pressure, or equivalent methods, with new generation natural substances having no chrome or arsenic.

Stainless steel screws are recommended to join wood pieces. Metal cramps are not recommended.

Plastic or rubber gaskets shall be flexible and unchanged over time.
They shall be soundproofing and placed where needed to prevent sound transmission, especially in the joins between the wood slats and the frame and between slats.


 1.2. Structure

The supporting structure of the soundproofing wooden panels shall be made of HE steel beams Fe 430 B (275 JR) hot galvanized in compliance with UNI EN 1461 regulation with minimum thickness of 60 micron, and base plate appropriate to the size of the barrier, and minimum dimension of mm. 250×280 and thickness of 15 mm.
The base plate shall be bead welded to the HE steel beams, anchored also by two angled base plates of 160×90 mm. and 10 mm. thick.
Alternatively, the HE steel beams can be immersed in concrete wells with minimum depth of 500 mm.


 1.3. Certifications

As final acceptance of the sound proofing panels and of its components, Alfakel shall provide results of technical tests conducted by authorized and/or licensed institutions to validate the technical specifications of the materials.

EN 1793-1:97 classification table A.1
Sound Absorption DLα = 14 dB
cat. A4

EN 1793-2:97 classification table A.1
Sound insulation DLR = 25 dB
cat. B3

Classification ISO 140/95-3 and ISO 717/96-1
Rw = 31 dB

Classification UNI EN 1793-1:1999, table A1
Reflection index DLRI = 4 dB
cat. A2

Classification UNI EN 1793-5:1999, table A1
Sound insulation index DLSI = 26 dB
cat. B3

The following shall be tested with positive results:
• Falling stones impact resistance compliant with EN 1794-1:98 annex C
• Wind resistance compliant with UNI EN 1794-1:98 annex A with impact load of 250 Kg/sq.m
• Brush fire resistance compliant with EN 1794-2:98.A

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