Seeing The Light
There have been many developments in highly insulating translucent cladding/translucent wall systems. Gideon Sykes looks at why these developments are so important to the creation of a pleasant working and playing ambience and the well-being of the occupants.
Maximizing daylighting is now considered to be fundamental to good design. Why? Because, in the same way that sunshine changes everything, so natural daylight, and diffused daylighting in particular, radically influences how people feel and how they react to and behave in the interior environment.
This is particularly true of schools where good insulated daylighting alters child behavior, calms them and improves learning.
The problem, of course, is to reconcile this with increasingly stringent regulations about energy loss through the building envelope. Happily, several glazing and translucent system manufacturers now offer new designs and new technology to provide effective solutions. One such solution, which emanated from the USA several years ago, claims to be the most highly insulating, diffuse light-transmitting, structural composite technology available. This is because other translucent materials cannot match the high performance and unique benefits of this system used for translucent walls and roofs.
The random distribution of glass fibers within the panels is designed to diffuse natural daylight evenly and deep within the interior space so that even direct sunlight is converted into evenly distributed illumination. In other words, this is ‘museum quality’ light without glare or shadows where the need for blinds and curtains is eliminated.
The system has increasingly caught the imagination of architects because they are able to maximize areas of wall or roof daylighting while minimizing energy loss, with consequent savings in the running costs of heating, aircon and artificial lighting. Obviously, the elimination of irritating glare and shadows also has important implications for the playing surfaces in sports halls and for the safety of swimmers in pools.
The system is inherently highly insulating because of its double skin panel construction which provides a U value of .23 (1.25W/m2K). However, this can be dramatically increased to provide a U value of .05 (0.28W/m2K) by including aerogel within the panels. Comprising 95% air, this translucent granular form of silica aerogel, developed by NASA, is the world’s lightest and best insulating solid material. All this means that architects and energy conscious designers can now maximize large areas of daylighting while reducing heat loss and, of course, still meet the stricter building regulations.
Importantly, well insulated daylighting will reduce energy consumption on heating, airconditioning and artificial lighting. It means that it is possible to install panels of translucent cladding and roofing systems where the insulating value can be as energy efficient as a solid surface and four times better than insulating glass units.
Good daylighting is vital to our well-being which is why we will stop at nothing, readily double or triple glaze or take whatever measures are necessary to maximize insulation without loss of enjoyment.
For example, good daylighting in schools has proved to have an extraordinary effect, showing a marked calming influence on pupil behavior and learning. Authoritative US research shows that learning rates are 20% higher in reading and math in classrooms with the most natural daylight. At the same time, daylighting has an enormous effect on health and well-being.
Daylight modeling is one way in which to calculate and guarantee the most effective daylighting for any type of building. It provides a lux level snapshot for any time of the day or year.
This is what informed architects and designers use to achieve the most effective specification. It takes into account proposed internal finishes, which could influence reflectance, the positions of other windows and any external influences, such as tall adjacent buildings or trees. With this information, the team can look at an individual room or at the overall situation and design the most favorable daylighting solutions. This service is usually provided free of charge as part of the planning of a particular project. To be at its most beneficial, the service should be used early in the design phase to help achieve the best possible results for the client and to form part of the overall building strategy and goals.
For example, daylight modeling will help with the documentation required to achieve BREEAM’s health and well-being credit for visual comfort which requires that 80% of the occupied space meets a minimum daylight factor of 2% (3% for exemplary level). This is the way to calculate the most effective daylighting for any type of building.
It can help quantify daylight transmitting products, determine optimal light transmission and help with positioning on a building to prevent glare issues and provide interior lux levels. Related to this are several other considerations. For example, Radiance Illuminance (measurement of light level) is a snapshot of the ambient lux level (light) at any given time. This tool calculates how effective is daylight penetration at any time of the day or on any day in the year.
Daylight autonomy (DA) is the percentage of the time-in-use that a certain user-defined lux threshold is reached only through the use of daylight. This is usually given as an annual value but seasonal, monthly and daily presentations can be made. It is the ideal way to achieve optimum natural daylighting conditions for the occupants, predicting when electric lighting may be required and thereby helping to reduce the cost of energy.
Finally, glare pattern analysis is the tool which calculates measurement of glare within a space. It is used to analyze glare (direct or reflected light) which is important to determine in many situations, such as in sports halls and swimming pools.
Clearly, innovative and highly insulating new daylighting technology is proving to be a valuable development process which will influence our use of glass and translucent materials for years to come.
There also exist plenty of aged buildings which urgently need repair and upgrading, especially where old curtain-walls and rooflights have failed and leak air. Solving these problems and converting older buildings into contemporary showpieces with the highest level of insulation can actually turn their disadvantage into benefits, with stunning improvements in both glazing performance and aesthetics and reducing energy costs.
Gideon Sykes is a marketing consultant for Structura UK
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