USAGE-The NOISESTOP LAAC 30 Acoustic Louvre is an all purpose external weather louvre with acoustically absorbent blade element specifically designed to reduce the level of noise passing through the opening into which the louvre is mounted. The NOISESTOP LAAC 30 Acoustic Louvre has a pleasant external appearance and will compliment any architectural design. The aerodynamic shape of the individual blades minimises the resistance to ainlow and the incorporation of water traps ensures that rain ingress is effectively eliminated. NOISESTOP LAAC 30 Acoustic Louvre can be installed as individual units or by bolting more than one unit together opening of any size can be accommodated. Each louvre has a robust outer framework which acts as a vertical mullion when several units are fixed together. If a continuous blade effect is preferred this can be supplied but individual requirements should be discussed with an NOISESTOP engineer. The main uses of NOISESTOP LAAC 30 Acoustic Louvre are in the control of mechanical fan noise, when used as the termination of a ducted air system, as fresh air intake and plantroom ventilation louvres in order to mask general purpose ventilation louvres in order to reduce aircraft or traffic noise. In all these application the louvres are normally built into structural openings and a number of alternative fixing arrangement can be supplied. NOISESTOP LAAC 30 Acoustic Louvre can also be used as a screen around equipment such as cooling towers or condensing units where an acoustic barrier is required and large volume airflows must be accommodated. In this application NOISESTOP LAAC 30 Acoustic Louvre may be supplied complete whit corner units, supporting steelwork, doors and dummy sections in order to form a completely self contained structure. It is a advisable that such applications be discussed whit an NOISESTOP engineer who will be pleased to assist you in the formulation of a detailed design layout.

CONSTRUCTION－Standard NOISESTOP LAAC 30 Acoustic Louvre are manufactured from high quality galvanized sheet steel. The louver frame and upper surfaces of the blades are formed from plain sheet and the under side of the blades from perforated sheet. The acoustic media contained whitin the louvre blades is inert non-flammable mineral wool and where a birdscreen is fitted to the rear face of the louvre this is made from galvanised steel wire mash having 12mm spacings. NOISESTOP LAAC 30 Acoustic Louvre can be supplied in aluminium, plastic coated steel or painted to suit the architectural and environmental design of the final installation. External or internal angle flanges can be supplied to fix louvres into structural openings and are normally manufactured from mild steel. The flanges are furnished already drilled for bolt fixing and if required can be constructed from the same material as the louvre itself. The louvre casing is pre-drilled through the sides of the unit to allow louvres to be bolted together or when units are to be fixed into a timber feame. Fixing details of individual louvres are normally supplied at the time of order but can be furnished on request. The height of the smallest NOISESTOP LAAC 30 Acoustic Louvre is 400mm and larger sizes increase in height by multiples of 225mm(i.e.625,850,1075mm etc.)up to a maximum height for a single louvre unit of 2425mm. All NOISESTOP LAAC 30 Acoustic Louvre have a standard depth of 300mm and widths are made to suit the customers requirements up to a maximum width for a single louvre unit of 1200mm.

TYPICAL SPECIFICATIONS－(into builderswork opening)－NOISESTOP LAAC 30 Acoustic Louvre shall be installed in the position indicated on the drawings to maintain the acoustic criteria shown in the specification. The acoustic louvre shall be constructed from galvanised sheet steel and be supplied complete with internal mounting flanges and birdscreens fixed to the rear face of the louvres. －(as acoustic screen)－A screen of NOISESTOP LAAC 30 Acoustic Louvre shall be installed aroud the cooling rower to a height of 2400mm. The screen shall be mounted on a pre-formed concrete plinth 300mm high and 350mm wide and supplied complete with dummy corner units, structural supports and a dummy louvre access door. The louvres to form a self supporting structure and the external finish to be black plastic coated steel.

Aerodynamic – It may be necessary to establish the correct size of acoustic louvre knowing that a certain pressure loss is required across the louvre for a given volume of air. In this case the face velocity of the louvre is read off the chart opposite and the slouvre dimensions established from the formula:
Airflow (Q)=Louvre face area(AL)×Louvre Face Velocity(VL) Conversely for a known duct size and airflow the pressure loss across the silencer can be obtained from the chart opposite. Selection Example: Assuming the airflow is 5m3/sec and the structural is to be made approximately 2000mm wide by 1500mm high From the formula above a louvre face velocity is established as VL=Q/AL=5/1.5=1.666m/sec From the chart opposite this gives a pressure loss of 3.3mmw.g. The exact louvre height nearest to 1500mm is 1525mm which would give a final louvre selection as shown below: NOISESTOP LAAC30 Acoustic Louvres – 2000mm wide x 1525mm high