Operating Box Louvre

An Operating Box natural ventilation louvre fabricated from Green Plastisol


A range of louvres designed to act as a source of controllable airflow either for inlet air or exhaust.



Individual units contain moveable blades which are mounted into robust box frames.

Louvre blades are adjustable to provide controlled ventilation.

Offered as single units or alternatively they may be mounted into continuous louvre banks to any height or width.

All units are suitable for mounting into cladding, glazing and brickwork with flanges formed to suit any mounting detail.

A comprehensive range of controls are available to suit specific requirements.


Offered in a choice of aluminium or steel, either in mill finish or post coated. Also available manufactured using pre-coated materials.

Aluminium units in aluminium alloy to BS EN 485 supplied in either mill finish or with a polyester powder paint finish (including Syntha Pulvin) with a wide choice of colours and gloss levels.

Steel units manufactured using galvanised steel in mill finish or with a polyester powder paint finish (including Syntha Pulvin).

Pre-coated units manufactured using Plastisol, PVDf or Colorcoat coated substrates in a full range of colours.

Also available using stainless steel, zinc, brass & copper sheet materials.

Aerodynamic Testing

The unit was subjected to a series of independently controlled tests to determine the aerodynamic performance of the design.

Aerodynamic co-efficient – 0.45


Numerous control options are available including; hand control (friction loaded), cable, pneumatic, electromagnet, electric actuator, etc.

Certain control options can incorporate a range of temperature rated fusible links if desired.

An additional option includes connection to smoke detection or building management systems when fitted in conjunction with electric and pneumatic control systems.

Manufacturing Options

  1. Top, bottom and side flanges may be formed to whatever mounting detail is required. For additional information please consult the separate form entitled Details Required for Manufacture.
  2. With flanged louvres, the box depth can be manufactured to fit inside or outside the building line as required.
  3. Expanded metal bird guards, security guards or fly mesh can be fitted internally or externally as required.
  4. Operating louvres can be sprung loaded to either open or close.
  5. Where units are to be mounted in continuous horizontal runs, joining plates are supplied for weathering.
  6. Fusible link shields – for use in buildings with sprinklers.


Units can be specified to have louvre blades adjustable to any position between fully open and closed to give infinitely variable amounts of airflow.


Louvre blades are pivoted on double bush nylon bearings. Maintenance should be carried out in accordance with McKenzie-Martin’s recommendations.

System Design & Product Selection

Assistance with scheme design and product selection is offered by our experienced technical team.