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Type NL
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Acoustic Louvre TROX GmbH Telephone +49/2845/2 02-0 Heinrich-Trox-Platz e-mail trox@trox.de

Contents · Description Description Construction · Dimensions Sectionalised construction Optional features Sound-attenuating external louvres Type NL are designed for use in air conditioning systems. They offer good protection against the ingress of rain and prevent birds and other small animals from entering into the system; however the louvre blades cannot offer a completely watertight barrier. Acoustic louvres of the Type NL are employed primarily when weather and noise protection are required in conjunction with louvres of reduced depth. Available as a double louvres, Type NLH, for...

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Construction · Dimensions Type NL Acoustic louvres Type NLS or NLA with aerodynamic section acoustically absorptive blades on a 150 mm pitch. Casing sides are pre-slotted for fixing into a builder's opening. Absorption material faced with glass cloth and perforated sheet metal. Rear side with bird screen using 12 x 12 x 1 mm galvanised wire mesh. Construction in single section (L = 300 mm plus bird mesh thickness). For acoustic performance see pages 6 and 7. Depth of louvre blade assembly is approx. 110 mm without acoustic lining; available with rear blanking plate. Special constructions...

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Sectionalised Construction · Optional Features Sectionalised construction Acoustic louvres are normally supplied in sections when either of the following dimensions is exceeded: B = 1800 mm The assembly of sectionalised louvres is on site, by others. Where louvres are in sections in both width and height, a 50 x 50 x 3 vertical box section frame is supplied to couple together adjacent sections, cover strips as well. Coupling frames are concealed behind cover strips. Material and finish to complement the louvre. The combinations illustrated below are available in louvre Types NL, NLH and...

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Installation Installation The vertical casing sides of the acoustic louvre are pre-slotted with 10 x 15 mm slots to facilitate fixing. Where supplied, architraves and picture frames are supplied loose and undrilled. On multisection units incorporating hollow section coupling frames, the frames are supplied drilled. in dB: Insertion loss per octave in Hz: Octave band centre frequency in dB: Sound power lever per octave in dB: A-weighted sound pressure level of air-regenerated noise in dB: Correction of LW for different widths in dB: Correction of LW for operating mode in dB: Correction of LW...

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Type NL Technical Data Insertion loss - Air-regenerated noise - Pressure drop Sound reduction index R and RW The test set up as described in DIN 45646/ISO 7235 with connecting ducts both ends is not really applicable for acoustic louvres. Therefore tests carried out in the TROX acoustic laboratories have been for the two most frequent occurring installations 'installation in walls with/without connecting duct, air inlet/air discharge', the measurement points being based on DIN 45646. Stated data for air-regenerated noise and pressure drop are valid for the modular heights listed. Data for...

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Type NLH Technical Data Operating mode Insertion loss De ; Sound reduction index R B Correction of air-regenerated noise and pressure drop for other sizes and operating modes Correction for width unequal to 1.0 m Width B in m ∆ LW Correction for operating modes Operating mode ∆ Pa Pressure drop : ⌬ pt, spec. = ⌬ pt x ⌬ Pa; in Pascal Sound power level of air-regenerated noise : A-weighted sound power level LW, A spec. = LW, A + ⌬ LW + ⌬ LA ; in dB octave band level LW, oct. spec. = LW, A spec. +⌬ Lrel.; in dB Diagram valid for width = 1.00 m and operating mode “A” Air-regenerated noise L W,...

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Order Details Specification text Acoustic louvres Type NL are suitable for installation in openings for supply and exhaust air. Compact construction for noise reduction and protection against the ingress of rain. Sound absorbing blades. Absorption material protected by perforated sheet. Insertion loss tested according to DIN 45646. Width in mm Height in mm Flow rate in l/s (in m3/h) Insertion loss (in dB) Sound reduction index (in dB) Max. permitted flow resistance in Pa (pressure differential) Construction Item Type Make TROX Order code For standard construction, no entry required NL Type...

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