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by Louise Watson, Faber Blinds UK Ltd Selecting office blinds was relatively simple twenty years ago - they needed to be durable, fabrics flame retardant, and neutral colours were the norm. Today the criteria for choosing appropriate solar shading have changed significantly, and indeed the products available. The process has become more complicated with extra legislation and many other factors to be considered, and as a result the solutions available have become much more sophisticated and interesting.
Creating a safe, comfortable environment is a top priority for most organisations and a working environment where temperature and glare are precisely controlled is beneficial for employee health, efficiency and morale. In addition to this there is the need to consider the EU directive "Energy Performance of Buildings" (2002/91/EC) which highlights a specific need in the building sector to promote the improvement of the energy performance of buildings through cost effective measures. This involves legislation such as the Document L2 amendment to the Building Regulations introduced in the UK with the prime aim of conserving energy as well as improving comfort in new build projects and certain types of alteration work. The project target is to reduce energy consumption in new buildings by 50%. So there would appear to be two conflicting targets: one to prevent light, glare and heat build up in the workplace, and the other to take advantage of natural light wherever possible to reduce the need for artificial light and so decrease energy consumption. The choice of solar shading, therefore, needs to be carefully considered.
Solar shading products are available for both internal and external applications, and a combination of both is increasingly used to achieve the optimal working environment. It is widely recognised that external blinds have a superior performance in reducing solar gain, however the control of glare rather than the reduction of heat is the more usual reason for specifying blinds for the commercial working environment in the UK and this can be satisfactorily achieved with internal blinds.
There are both venetian and roller systems specifically designed for external use, and awnings which are rapidly gaining in popularity for commercial applications. This is due in part to the fact that they are a perfect combination with internal blinds. It is even possible to have an awning that performs like an external roller blind and drop arm awning, such as the Faber Markisolette 840.
For internal blinds a wide variety of products is available: roller, venetian, vertical, pleated, even wood and roman blinds all have a role to play in the office environment. Roller blinds/roller sunscreening systems are probably one of the most popular and combined with the many highly efficient screen fabrics provide a most effective solar shading solution for offices and other commercial premises where control of glare on computer screens is an essential requirement. With screen fabrics, even when the blind is fully down, there is a still a view to the outside, something that makes a significant contribution to the well being of the workers inside.
One of the factors determining the choice with these fabrics is the degree of openness, which ranges from the very dense 1% to the very open 10%. At present the largest portion of business is with 3%, although this could very well change as a result of the latest legislation on energy conservation. By providing a combination of external and internal blinds, a higher degree of openness such as 10% would be sufficient to control glare and allow a greater level of natural light into the building. With these fabrics it is also possible to have the same fabric in different degrees of openness, so the correct level of openness for each elevation can be provided and still maintain uniformity of appearance throughout the building.
Screen fabrics are not the only choice for roller blinds, there is a wide range of fabrics available with many different specialist coatings on the back to provide solar reflective, dim-out and blackout properties. Densely woven/non woven plain fabrics can also provide cost-effective solar shading and are generally available in a good range of colours, so giving the specifier more flexibility with the overall decoration scheme. The 'Guardian' range from Louver-Lite is a good example of this.
Venetian blinds are another widely used type of 'office blind' and probably the oldest established. They are popular because they are durable, economical and available in a range of slat sizes as well as an excellent choice of colours and finishes. They can be adjusted to reflect the light up to the ceiling, brightening the room without heat gain or the necessity to turn on the lights. Venetian blinds can also stop approximately 40-60% of the sun's radiant energy, depending upon the choice of colour and type of system specified. It is possible to have blinds with no holes in the slats - for example the Luxaflex Lightline from Hunter Douglas - and blinds with wide laddertapes to avoid shafts of light through the slats and better light exclusion when the blind is closed.
When considering office blinds and the need for daylight in the building, the use of glazed internal partitions can also play a role in energy conservation and here venetian blinds come into their own with systems designed to fit neatly between the double glazed panes of partitioning systems. The blinds can be left open for optimum light distribution and closed when privacy is required. Tilt only control is the standard system of operation for this type of blind, but raise/lower as well as tilt options are also available.
Vertical blinds are another type of louvre blind that provide excellent light control and are available in a wide choice of fabrics. These blinds are also perfect for very large areas of glazing, as a blind up to 7m wide and 5m drop (subject to weight of fabric) can be supplied on a single head rail. A number of control and draw options, and systems where the head rail can be curved or bent to fit bay windows and arches make these blinds very versatile indeed. In addition the range of fabrics available includes many of those used for roller blinds, so with vertical blinds it is also possible to have screen and other performance fabrics. This has the added benefit of enabling a combination of roller and vertical blinds to be used in the same building with complete uniformity.
Vertical blinds can also be supplied with metal, PVC and wood louvres, which further increase the options available with this versatile sunscreening product. The range of options for interior shading solutions is very varied in terms of product availability, style and choice of colour. This article has only briefly touched on the three main products, but there are many more. The final choice will depend on many factors but in each case colour should be a major consideration in the selection process and will directly affect brightness, glare and heat gain (shading coefficient). Light colours are more reflective with lower heat gain properties but allow a higher percentage of daylight and solar transmittance into the building. Darker colours absorb light and heat and are therefore less energy efficient, but do have a lower surface brightness, thereby reducing reflectivity and providing an excellent glare-free environment for PC users.
Achieving the right balance between solar protection and natural light provision is almost a science in itself, but with the extensive range of products now available and the technical information to accompany them, there is every opportunity to provide the very best solution for each individual project.
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