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Economical, ecological and aesthetic louvre window for smoke ventilation.

Features and Benefits:

  • NSHEV certified in accordance with BS EN 12101-2.
  • Programmable electric drive functions through SCS software.
  • Available in a range of sizes.
  • Provides good thermal performance.
  • Additional passive and active anti‑trap protection system for the main closing edges with reversing function.
  • Can be glazed into curtain walling or directly into structural openings.

General information

Insert requirement, 2500 mm maximum frame width.

Uniclass 2015
Pr_70_65_04_56 Natural smoke and heat exhaust ventilatorsPrimary
Specification data - Natural smoke and heat exhaust ventilators
Product Reference

NSHEV Glass Louvre FLW 32

32 mm depth, up to 1.1 W/m²K U-value (triple glazed).

NSHEV Glass Louvre FLW 40

40 mm depth, up to 0.8 W/m²K U-value (triple glazed).


Insert requirement, 2500 mm maximum frame width.

Louvre blades -


Insulated aluminium panel



Insert requirement, available 200–450 mm for FLW 32 and 250–500 mm for FLW 40.

Glazing adapters

17 x 32 mm

For FLW 32 only.

17 x 40 mm

For FLW 40 only.

25 x 32 mm

For FLW 32 only.

25 x 40 mm

For FLW 40 only.

Special order

Insert requirement.





Standard product features


Louvre frames have mitred corners with internal brackets, and are screw-fixed. Louvre blades are centre-pivoted and close flush with the external vent frame.

Frame construction:

Thermally broken aluminium extrusions. Frame sections have mitred corner with internal brackets and are press-formed.

Frame depth:

  • Louvres: FLW 32: 49 mm; FLW 40: 51 mm.
  • Vent: FLW 32: 77 mm; FLW 40: 85 mm.

Visible frame width:

  • Louvres: FLW 32: 21 mm; FLW 40: 28 mm.
  • Vent: FLW 32: 20/ 40 mm (horizontal/ vertical); FLW 40: 40 mm (horizontal and vertical).

Louvre blades:

23–40 mm thick, includes ethylene propylene diene monomer (EPDM) gaskets.


Concealed rack and pinion mechanism provides easy to use, maintenance free, smooth and synchronized operation of the louvre blades.

Technical characteristics:

  • Barrier load: Tested BS 6180.
  • Impact resistance: In accordance with DIN 18032-3.
  • Security (to BS EN 1627): RC2.
  • Coefficient of discharge: Cv. 0.57 (maximum).
  • Wind load classification: Up to WL 3000.
  • Resistance to heat classification: B 300-E.
  • Reliability classification: Re 1000.
  • Low ambient temperature classification: T (‑05°C).
  • Air permeability (to BS EN 12208): Class 4.
  • Watertightness (to BS EN 12208): Class 7A (FLW 32) / Class 8A (FLW 40).
  • Tested sound reduction (Rw): 41 dB.

Third party certifications
  • NSHEV: Certificate: In accordance with BS EN 12101-2
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