Weaving your narrative - by the Lighting Journal
Having to compromise on your lighting unit choice or the aesthetic of a unit in order to meet regulatory requirements, neutralise glare or to conceal your light source is the sort of compromise that, while sometimes unavoidable, will always pain any self-respecting lighting designer.
Obtrusive external louvres, visors, hoods, films and baffles fitted to control light spill or light pollution are often considered something of a necessary evil. Not only do they interrupt the lighting unit’s design and form, they generally negatively impact on the light output ratio (LOR) and purity (CRI).
But at Smartlouvre, by revisiting and rethinking technology from the 1940s, we have come up with what we feel is an innovative solution that can enable lighting designers to avoid these sorts of painful compromises.
The MicroLouvre (and we’ve trademarked the name) is a simple, engineered metal louvre fabric that has been made to fine tolerances and which is designed to provide exceptional control and diffusion of sun, heat, light and air.
It comprises 17 paper-thin durable bronze louvres woven into every inch of the fabric, and the fabric itself is only 1.5mm thick. In fact, we believe it is the world’s thinnest and lightest metal louvre fabric.
FORTIES WEAVING MACHINES
The link to the 1940s is that, to create the product, our technicians went back to the original fabric-weaving machines designed by Dow’s John J. Grebe, and spent years modernising them, computerising them and improving the overall weaving efficiency. Ultimately though, the machines, the process and the material first produced back in the 1940s remains the same today.
So, what’s the deal here in terms of lighting and lighting performance? The paper-thin angled louvres act as a directional lighting filter, allowing light to pass through in one direction whilst reducing the visual impact of the light source from the opposite direction, without limiting the LOR or CRI.
The louvres are weaved into the fabric at angles of 17° or 0° as standard, but the material can be customised to any angle as required.
Because it is so thin and easy to manipulate, the metal fabric can be integrated into new products, or retro-fitted to lighting units. It is usually installed easily under the glass cover without the need for any adjustments to be made to the casing.
The angled louvres mitigate unwanted light trespass, light spill and glare without the need for oversized external fittings that can interrupt the aesthetic of the unit, not to mention adding weight and increasing the size and therefore space required for the unit.
REQUIREMENTS AND REGULATIONS
With its 80% open area, the fabric permits optimum light transfer, ensuring high energy efficiency and full CRI. In photometric testing, carried out with several manufacturers of high-powered lighting units from uplighters to flood lights, there has been no reduction in intensity or output recorded.
The fabric holds an A1/A2-s1.d0 Fire Rating classification according to BSEN 13501-1:2007+A1:2009 and in tensile performance testing a 1m² panel of fabric, tensioned under load proved a uniaxial stress factor of up to 25kgf/m².
Being lightweight and strong as well as meeting A1/A2 Fire Rating standards, the fabric can be used in a wide range of lighting applications, everything from display lighting, photographic units, spotlights, wall washing, traffic lights, street lighting and heritage lighting.
The fact it is made from bronze also means it is corrosion-resistant, so making suitable for indoor or outdoor use.
Angular selective technology used in production of the fabric can provide anti-glare louvres for either a symmetrical beam or asymmetrical light kick, to suit the application. We can also, naturally, customise for new product developments or specific project requirements.
HOW IT WORKS IN PRACTICE
To give a sense of how the MicroLouvreTM product can work in practice, and the sort of difference it can make, the architectural lighting specialists StudioFractal and its partners, used the product on a project to create the first new public square in London for 150 years, a functional space with heaps of character at King’s Cross Square, St Pancras.
StudioFractal worked with lighting designer acdc to realise its design for this historic piece of architecture, and we supplied louvred metal fabric to neutralise the glare from the in-ground luminaires.
The result has been a cleverly designed (and expertly hidden) LED lighting scheme that defines the furniture and structures in the square at night. In fact, a perfect blend of functional and accent lighting!
The light grazes up the ground floor of the building to reveal the brickwork. The integrated metal louvred fabric works to hide the light source whilst maintaining an integrated balance of glare control and high lumen transmission.
The varying lengths of the space and the nature of use of the historic building as a public space restricted the designers from using any external fittings to the lights, because of health and safety regulations. The internal application of the metal louvred fabric therefore allowed the luminaires to perform and to meet the desired effect.
As StudioFractal’s Chris Sutherland has explained: ‘As well as highlighting the broad expanse of the façade, we wanted to gently pick out the small niches and cornices with the same lighting effect.
‘The product we used needed to be available in a range of lengths to suit the variation in space available. Being grade listed meant that the luminaire fixings had to be located in existing mortar lines to ensure no damage was done to the façade,’ he added.