dwg AVX-1810 · Products
Louvres for ventilation and screening.
A mesh louvre consists of angled blades in a frame. Woven, welded or expanded mesh can be fitted in front or behind them. The panel passes air or gas and can provide protection against rain, sunlight, views and windblown debris according to its design. Mesh can also restrict birds, vermin and hand access. Overlapping blades redirect the flow and drain water along the blades and frame. Free area and rain rejection apply to the tested blade pitch, angle and frame depth within the specified velocity range.
Also known as: weather louvre · louvre panel · lamella grille · ventilation louvre · sand trap louvre · bird mesh louvre
A ventilation opening must pass enough air and suit its exposure to rain and debris. Blades and mesh occupy part of the opening. If this is overlooked, airflow may be too low. Insufficient rain protection or bird mesh can also allow water, contamination and nesting behind the louvre. Assess free area and required rain rejection alongside size and colour.
We supply mesh louvres to the opening dimensions. Blades can be plain, perforated or mesh-faced. Materials include aluminium, galvanised steel and stainless. The frame is selected for the façade or plant room. Include the structural opening and air volume in the enquiry. State the fixings and exposure, including coastal or high-level mounting. A measured photograph or building drawing helps assessment. Availability and lead time are confirmed at quotation.
Blade geometry determines the balance between free area, pressure loss and screening. Wider pitch provides more area but can reduce rain rejection. Bird mesh reduces free area further. A deeper acoustic profile attenuates noise and may reduce free area by about a third, depending on the design. State the priorities for air, water, sound and views. Process-gas droplet separation uses deeper, more closely spaced blades with drainage. These can operate at higher velocities than knitted mesh pads. See our demister page and include gas rate in the enquiry.
| Property | Value |
|---|---|
| ≈ 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. They are not a commitment. Blade pitch, angle and free area are confirmed per application after technical review of the opening, airflow and exposure. The same applies to frame and panel size. Pressure-drop and rain- or sand-rejection figures belong to a specific tested profile. Figures on this page are not a performance guarantee for a supplied panel.
The face area is larger than the free area between the blades. Free area may be half the opening or less. Mesh reduces it further. Include airflow and available pressure alongside the structural opening. Distinguish geometric from aerodynamic effective free area. The first comes from the minimum geometric opening. The second comes from an EN 13030 airflow test and is lower.
Profile selection considers rain, sand and sun. Views, bird exclusion and hand access may also matter. Wider blade pitch promotes airflow. A double bank with a hooked profile and rear gutter can improve rain rejection. Vertical blades are used for sand trapping. Acoustic blades with absorbent cores attenuate noise but reduce free area. State which requirement takes priority.
State the structural opening and whether the louvre fits in the reveal, over the façade or in a curtain-wall grid. Channel, flanged and concealed frames need different mounting space. Include available depth and wall construction. Wind loading is needed for high or exposed mounting. Large openings are divided with mullions at drawing stage.
Assess aluminium for low weight and coastal façades. Galvanised steel is an option for milder exposure. Assess 304 and 316L for hygiene, washdown and chlorides. Check contact between blades and mesh, mullions or fixings of other metals. This can cause corrosion in wet or salty conditions. Cutting after coating leaves bare edges. State the coating system and any subsequent machining.
Extruded aluminium is common for building openings. It can be supplied mill-finished, anodised or powder-coated to a RAL colour. Hot-dip galvanised and coated steel is an option for moderate exposure. Stainless 304 is used for hygiene areas. Assess 316L for chlorides, cleaning chemicals or coastal exposure. Duplex and higher alloys are possible for specific applications. Mesh, mullions and fixings are supplied in the same material family unless otherwise specified. With different metals, corrosion risk must be assessed. Availability and lead time are confirmed at quotation, including for less common materials and coating systems.
Weather louvre describes the function: rain protection for an opening that must pass air. Mesh louvre describes construction with mesh in front of or behind the blades. This may provide a uniform surface or bird and vermin exclusion. One panel can combine both functions. State the required screening.
Divide airflow in m³/s by the required velocity in m/s. Around 2 m/s is a common intake starting point; higher values require assessment of noise and water carry-over. The result is the required free area in m². Divide this by free area expressed as a fraction of face area. At 50 %, face area is twice the required free area. Allow for mesh as well. Send airflow and the available opening for assessment.
Yes. Woven or welded bird mesh may typically reduce free area by about 10 to 20 %. The effect depends on aperture and wire diameter. Insect mesh reduces it more. Include mesh in sizing from the start and provide access to remove leaves and seeds.
Rain rejection applies to defined test conditions and is not unlimited. State any required class to EN 13030 for rain rejection or EN 13181 for sand penetration. The class belongs to a specific tested profile. The profile and evidence are confirmed at quotation. If the space behind must remain dry, drainage also needs assessment, for example with a rear gutter or drip tray and drain.
Aluminium with a marine coating system is an option for exposed façades. Assess 316L for continuous chlorides or cleaning chemicals. Galvanised steel may suit sheltered or inland sites. Check contact between different metals. Steel on aluminium can cause galvanic attack in wet or salty conditions. Use suitable combinations or electrical isolation.
Single panels up to approximately 2000 × 2000 mm are common in many profile systems. Some allow larger sizes. Larger openings are often divided with mullions to allow manageable transport and fitting. State the opening, fixing surface and installation method so the layout can be prepared in advance.
Yes. A vane pack redirects gas around deeper, more closely spaced blades. Droplets strike the blades and drain away. These packs can operate at higher velocities than knitted mesh pads and tolerate solids better. Their separation cut is generally coarser. See our demister page and include gas rate, pressure and liquid load in the enquiry.
State the structural opening and mounting position. Include airflow, available pressure and required protection. Add fixings, material and finish. Wind loading is needed for high or exposed mounting. A measured photograph helps. Free area, profile and size are confirmed after technical review along with availability and lead time.
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