Specifications for:
Alfa BS
Sound Insulating and Sound Absorbing Wooden Barrier – A4/B3 Categories


 1.1. Wooden Panels

Soundproof and sound absorbing panels EC approved with high sound absorbing power made with first quality resinous wood compliant with UNI EN 350/1 regulation; treated in autoclave vacuum under pressure per DIN 68800 part 3 regulation.
The structure is made of a box-shaped solid wood support frame, with minimum cross-section of 100×80 mm., and the wood panels are jointed together to improve stability. Inside the frame shall be placed the sound-absorbing material made either of mineral fiber underlayment compliant with regulation EN 13162:2001-10, 50 mm. thick with density of 90 Kg/m3, or made of polyester fiber 50 mm. thick with density of 50 Kg/m3. The panels shall be supported by spacers to create a resonant chamber between the back of the frame and the insulating material (the hookup of the underlayment must meet the Technical Specification requirement of FFSS (Italian National Railways).
The material shall not decay, shall be weather and chemical agents resistant, fire proof or self-extinguishing, and shall not emit harmful toxic gas.
The side facing the noise source shall be coated with a sheet of silicon high-density polyethylene (HDPE) green (or another color upon request) 163 ± 4 gr./m2 grammage and warp diameter of 0.285 mm., > 90% degree of darkening, weather and UV resistant, fixed to the panel’s frame.
Towards the noise source the finishing shall be made of 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 and also to break down the sound waves.
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.
Onto the vertical sides of the panels shall be inserted EPDM gaskets to strengthen the sturdiness of the panel within the HE steel profiles and also to guarantee soundproofing.
Additionally, a flat EPDM gasket of 5 mm. thickness shall be placed on the end part of the panel to prevent gaps between the stacked panels.
The panel standard sizes vary from 1000/1500/2000 mm. heigh and 2950 mm. length.
To ensure traffic safety in case of fire, the panels (though flammable) shall be fire resistant (Class 1 flammability rating required). The posts shall be fireproof and acts as fire barrier.
Special care shall be applied to the joins, in consideration of possible swelling and shrinking of the material.

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.
The gaskets shall be made of EPDM and comply with the regulations expressed in DIN 53571 and DIN 53504.
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.
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 1793-2:97 classification table A.1
Sound absorption DLα = 12 dB
cat. A4

EN 1793-2:97 classification table A.1
Sound Insulation DLR = 29 dB
cat. B3

Classification ISO 140/95-3 and ISO 717/96-1
Rw = 34 dB

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

Classification UNI EN 1793-2:1999 table A1
Sound insulation index DLSI = 26 dB
cat. B3

Furthermore, positive test results shall be provided for the following:
• 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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