Colt 3UL

Triple bank Universal Louvre fixed metal weather louvre system

Colt 3UL Universal Louvre is a roll-formed triple bank louvre system designed for applications requiring ventilation with the maximum degree of rain defence.

When some degree of rain penetration can be tolerated, we would recommend 2UL. When rain defence is not of primary importance, we recommend the use of 1UL.

Features and benefits

  • Highly aerodynamically efficient
  • Enhanced rain defence performance
  • Durable and maintenance free
  • Thermal expansion of the louvres is accommodated by the design
  • Proven performance
  • Easy to install
  • A wide range of options

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Aerodynamic performance (to EN 13030)

  • Universal Louvre 3UL/SH - achieves coefficient class 4 in accordance with EN13030. Ce = 0.196 (no bird guard).
  • For data on 3UL/DH (deep) versions, please contact Colt.

Rain defence performance (to EN 13030)

Class A - up to 2.5m/s suction velocity (no bird guard)

Class B - up to 2.5m/s suction velocity (with bird guard)

Class C - up to 3.0m/s suction velocity

Class D - 3.5m/s suction velocity

Triple bank louvres offer maximum rain defence.

For data on DH (deep) versions, please contact Colt.


Tested, independently, to EN 13030 : 2001


  • System Types
  • Configuration
  • Material
  • Texture
  • Colours/ finishes options
  • Paint coverage
  • Guards
  • Blanking panels
  • Noise control
  • Accessories

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Universal Louvre - NBS Specification


Screening and ventilation louvre datasheet

Highly aerodynamically efficient – this reduces pressure drop, allowing the building opening to be minimised thereby saving installation costs. Reduced pressure drop also minimises energy consumed by ventilation fans.

Enhanced rain defence performance - 3UL has high resistance to rain ingress. Unlike other louvre types, 3UL panels have efficient drainage paths integrated into their hollow section mullions, which in practice further increases their rain defence effectiveness.

Durable and maintenance free – UL is made from corrosion resistant materials.

Thermal expansion of the louvres is accommodated by the design – the louvres are clipped (and not riveted or screwed) to structural supporting mullions.

Proven performance - UL has been tested to EN13030 : 2001.

Easy to install – UL can either be delivered to site pre-assembled (panels up to 6 sqm) or assembled on site.

A wide range of options - available in various shapes, configurations, materials, finishes and coatings to meet the requirements of almost any project.

Louvres are roll-formed; either mill finish, polyester powder painted or anodised; plain, perforated or embossed.

Louvre panels can incorporate mitred corners, special shapes and louvre doors. Colt also has a range of turret units.

If noise reduction is required, acoustic louvre panels may be used.


System Types

  • Universal Louvre 3UL/SH - Triple bank shallow section, front louvres at 50mm pitch
  • Universal Louvre 3UL/DH - Triple bank deep section, front louvres at 100mm pitch


  • Horizontal
  • Horizontal inverted
  • Vertical


  • Aluminium
  • Mild steel
  • Stainless steel


  • Plain
  • Perforated
  • Embossed

Colours/ finishes options

  • Mill aluminium
  • Anodised aluminium
  • Polyester powder coated to a RAL colour, list of colours upon request

Paint coverage

  • Not relevant
  • Total
  • Partial


  • None
  • Aluminium bird guard
  • Galvanised steel bird guard
  • Stainless steel bird guard
  • Insect mesh

Blanking panels

  • None
  • Single skin aluminium panel, mill finish
  • Single skin aluminium panel with external decorative polyester powder paint finish to match louvres
  • Insulated panel

Noise control

  • None
  • Where attenuation is required 3UL can be integrated with the Colt Acoustic Louvre Module (CALM).


  • None
  • Doors - single / double, outward opening
  • Turret unit(s)