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dwg AVX-1810 · Produits

Mesh louvres & lamella panels

Air through. Everything else out.

Définition

A mesh louvre is a bank of angled blades in a frame, faced or backed with woven, welded or expanded mesh, that lets air or gas pass through an opening while rain, sunlight, line of sight, birds and windblown debris do not. Each blade overlaps the one below it: the stream is turned twice around the profiles and carries on, while water runs down the blade face into the frame's drainage channel and out. The mesh — over the blades for one even surface, or behind them as bird mesh — is what also makes the panel a barrier against vermin and hand access. A louvre holds its stated free area and rain rejection only while blade pitch, angle and frame depth stay as they were tested and the velocity stays inside the profile's working band — open it up for more airflow and the protection goes with it.

Également appelé: weather louvre · louvre panel · lamella grille · ventilation louvre · sand trap louvre · bird mesh louvre

It shows up after the first driving rain, or in the first warm week. Water on the floor under the intake and rust streaks down the wall. A fan that will not reach its duty, because the opening was sized as a hole and then half of it was filled with blades. A bird's nest behind the bottom blade, in a building with a hygiene audit next month. In almost every case the louvre was chosen on the size of the opening and the colour, and never on the two numbers that decide how it behaves: free area and rain rejection.

We supply mesh louvres and lamella panels to the opening — blades plain, perforated or mesh-faced, in aluminium, galvanised steel or stainless, with the frame type your façade or plant room needs. Send the structural opening, the air volume that has to pass, the fixing arrangement and the exposure. A louvre in a machine enclosure is a different panel from one four floors up on a coastal elevation. A photograph with a tape held in the opening is a usable start; a builder's drawing is better. Availability and lead time are confirmed at quotation.

Every louvre is one trade-off, settled once, in the blade geometry. Open the pitch and you gain free area and lose rain defeat; close it and you gain protection and spend the fan's pressure. Put bird mesh behind it and another tenth or more of that free area is gone. Deepen the blade for acoustics and a third of it goes. No profile wins on every axis, so name the requirement you cannot trade — air, water, sound or sight — and the rest follows from it. In process gas the same geometry does a second job: a deeper, closer blade bank with a drainage hook knocks droplets out of a stream at velocities where a knitted mesh pad would re-entrain them. If that is your duty rather than a building opening, start from our demister page and send the gas rate with the enquiry.

dwg AVX-1810 · aluminium / steel / 304 / 316L

Où il est utilisé

spec.json ↗
Mesh louvres & lamella panels · AVX-1810
Propriété Valeur
≈ 50–100 mm centre to centre (standard range); closer on storm and sand profiles
30–45° typical; also 0° drainable and vertical sand-trap profiles
geometric free area ≈ 30–60 % single bank, ≈ 20–40 % double bank or acoustic; the aerodynamic (effective) free area from an EN 13030 airflow test is lower
commonly up to ≈ 2000 × 2000 mm as one panel; some profile systems allow larger — bigger openings are built up as a bank with mullions
woven, welded or expanded facing over the blades; bird mesh typ. 12–20 mm aperture, insect mesh finer
≈ 40–150 mm weather louvre; acoustic ≈ 100–900 mm depending on the attenuation required; channel, flanged or concealed frame
≈ 1.5–3.5 m/s through the free area (core velocity); pressure drop is profile-specific and read off the tested curve — in the tens of Pa at intake velocities
extruded aluminium, mild steel (galvanised), 304/316L; Duplex and higher alloys on request
mill, anodised, polyester powder-coated to RAL, hot-dip galvanised or a marine coating system

Values shown are standard industry ranges for louvre and lamella panels, not a commitment. Blade pitch, angle, free area, frame type and panel format are confirmed per application after technical review of your opening, air volume and exposure. Free-area, pressure-drop and rain- or sand-defeat figures belong to a specific tested blade profile — no figure on this page is a performance guarantee for a supplied panel.

Ce qu’il faut préciser

Free area, not the size of the opening

A louvre is quoted as a face size but behaves as its free area. Half the opening or less is what actually passes air, and any mesh behind the blades takes more. Give us the air volume and the pressure you can spend along with the structural opening, and the panel is sized from those. Ask whether you are being quoted the geometric free area or the aerodynamic one: the geometric figure is the minimum area drawn between the blades, the aerodynamic (effective) free area comes out of an EN 13030 airflow test, and the measured figure is always the lower of the two.

What the louvre has to stop

Rain, wind-driven sand, sun, line of sight, birds, hands, noise — each pulls the geometry a different way. A single bank at a generous pitch moves air cheaply. A double bank with a hooked profile and a rear gutter defeats driving rain. Vertical blades trap sand. An acoustic blade with an absorbent core cuts noise and a third of your free area with it. Name the one requirement you cannot compromise and the profile follows from that, not from a catalogue page.

Frame, fixing and the hole in the wall

Give the structural opening rather than the panel size, and say whether the louvre sits in the reveal, over the face, or in a curtain-wall grid. Channel, flanged and concealed frames mount differently and each consumes a different slice of the opening. Add the frame depth available, the wall build-up, and the wind load if the panel is high or on an exposed elevation. Openings above single-panel size become a bank with mullions — decided at drawing stage, not on the scaffold.

Material, finish and what touches what

Choose for the environment: aluminium for weight and coastal façades, galvanised steel where cost governs and exposure is mild, 304 or 316L for hygiene, washdown and chlorides. Then check the assembly. Bird mesh, mullions or fixings in a different metal from the blades can corrode at every contact point — on a wet or salt-laden elevation they usually do. A coating applied before cutting leaves a bare edge exactly where water stands. State the finish system and whether anything is cut or drilled after coating.

Matériaux & variantes

Extruded aluminium is the standard for building openings — mill finish, anodised, or polyester powder-coated to a RAL colour. Mild steel, hot-dip galvanised and coated, where cost governs and exposure is moderate. Stainless 304 for hygiene areas and 316L where chlorides, washdown chemicals or a coastal position are in play. Duplex and higher alloys are possible for specific duties. Bird mesh, mullions and fixings are supplied in the same material family as the blades unless the specification says otherwise — mixing families is what usually ends a louvre early. Availability and lead time, including for the less common materials and finish systems, are confirmed at quotation.

Internes de réacteur (screens & supports) Tôles perforées Filtration & industrie de process Construction de machines & OEM

Questions fréquentes

What is the difference between a mesh louvre and a weather louvre?

The two names describe different things about the same panel. "Weather louvre" says what it is for: keeping rain out of an opening that still has to breathe. "Mesh louvre" says how it is built: the blades are faced or backed with mesh, for a uniform surface, for bird and vermin exclusion, or for both. A panel can be either, or both at once. Say what has to be kept out and the construction follows from it.

How large a louvre do I need for a given air volume?

Work back from free area, not from the hole in the wall. Divide the air volume by the velocity you can accept through the free area — around 2 m/s is a common working figure for an intake, higher where noise and water carry-over allow. That gives the free area in m². Divide it by the free-area percentage of the panel and you have the face size. A 50 % panel therefore needs twice the wall opening a naive calculation suggests, and bird mesh takes another slice. Send the volume and the opening you have; if the two do not agree, it is better to know now.

Does bird mesh reduce the airflow?

Yes, and by more than most people budget for. A woven or welded bird mesh behind the blades typically removes 10–20 % of the free area you have just paid for — how much exactly follows from the aperture and the wire diameter — and an insect mesh takes considerably more. Put it in the sizing from the start rather than adding it after the panel is made. It also has to be reachable: mesh that cannot be cleaned blinds with leaves and seed and turns a ventilation opening into a pressure drop.

Will a louvre keep driving rain out completely?

No profile stops all water at all wind speeds. A louvre is rated by how much it lets through under a defined test, so if your specification calls for a rain-defeat class to EN 13030, or sand penetration to EN 13181, state it with the enquiry. That class belongs to one specific tested blade profile, not to louvres in general, so the profile and its evidence are confirmed at quotation. Where the room behind may see no water at all, a drainable blade with a rear gutter, or a louvre with a drip tray and drain, is the honest answer.

Which material should I use on a coastal or chemically loaded site?

Aluminium with a marine-grade coating covers most exposed façades. 316L where chlorides or washdown chemicals are constant, galvanised steel inland or behind a screen. The mistake that ends the panel early is mixing families: a steel bird mesh or steel fixings on an aluminium louvre can corrode the aluminium at every contact point, and on a wet or salt-laden elevation usually do. Blades, frame, mesh and fasteners belong in one material family, and where they cannot be, they have to be isolated.

Can you supply one panel for a large opening?

Up to roughly 2000 × 2000 mm a single panel is normal in most profile systems, and some allow more. Above that the opening is built up as a bank with mullions, which also keeps handling and transport to something a crew can manage. Give us the structural opening, the fixing surface and how the panel reaches its position, and the split is set on the drawing rather than on the scaffold.

Can louvre blades separate droplets from a gas stream?

Yes — that is a vane pack, the same idea run harder. The gas changes direction twice around deeper, closer blades, the droplets cannot follow the turn, they strike the blade and drain away. Vane packs work at higher velocities than a knitted mesh pad and tolerate solids better, at the cost of a coarser cut. If your duty is process gas rather than a building opening, start from our demister page and send the gas rate, pressure and liquid load.

What do you need for a quotation?

The structural opening and whether the panel sits in the reveal or over it, the air volume and the pressure available, what has to be kept out — rain, sand, birds, sight, noise — the fixing arrangement, the material and finish, and the wind load if the panel is high or exposed. A photograph with a tape in the opening covers most of it. Free area, profile and format are then confirmed after technical review, together with availability and lead time.

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