Building services engineers will often find themselves in the unenviable position of trying to meet a variety of demands, all of which are considered to be equally as important and at times will often appear to have conflicting requirements.
The design and installation or retrofit of an office lighting scheme is an example of a task that often comes within a building services engineer’s remit. With mounting legislation and environmental pressures to reduce the carbon emissions of a building, it is a task that must be handled carefully in order to ensure that the best lighting scheme is achieved through the installation of energy efficient lamps.
Lighting design is at its best when the designer has taken into account the nature of the space and its purpose. Any space that needs to be lit should be divided into different areas for different functions for the purpose of defining the best lighting scheme. These areas could be workstations, corridors, entrances, meeting rooms or break out zones. These zones should be defined according to the tasks to be performed in them and their functionality.
Once zones have been designated within a building, building services engineers should decide which lighting effects will best serve the intended purpose of each area. Depending on the requirements of the lighting scheme, one or more different types of lamp may be needed.
When it comes to upgrading a building’s existing lamp technology – it is far easier than people think. The market now accommodates a wide range of energy efficient lamps that are suitable for all applications. Lamps based on halogen, compact fluorescent and LED technology all provide significant energy savings in comparison with traditional incandescent lamps. Significantly, these lamps all comply with the new EU Directive that began on 1 September which calls for a gradual phase out of inefficient lighting products over the next few years.
Energy efficient halogen lamps such as those in Osram’s Halogen Energy Saver lamp range allow easier retrofitting of all conventional halogen lamps and existing incandescent lamps as they fit into traditional holders. These lamps provide 30% energy savings and also benefit from being fully dimmable. By installing these lamps, building engineers can avoid large investment costs as they have a payback period of less than one year due to the reduction in energy consumption, which leads to lower energy bills. In addition, significant time allocation to replace an existing lighting scheme might have prevented a switch in the past, but these lamps are very quick to retrofit and their long lifetime leads to reduced maintenance costs.
There is an unlimited number of ways in which style elements and lighting effects can be combined so it is worth consulting a lighting designer to decide upon the final lighting scheme. With the aid of initial estimates and computer software, it is possible to define the number of light sources required, their wattage and other technical specifications. This stage should go hand in hand with specifying the luminaires.
Specifying a scheme
Building services should consult Part 1 of DIN 5035 when specifying a lighting scheme as this provides definitions and general requirements for artificial lighting. Part 2 of DIN 5035 defines the guideline values for workplaces interiors and exteriors and includes the following minimum requirements for lighting in the workplace:
- General lighting and/or special lighting (task lamps) must be dimensioned and arranged so that lighting conditions are satisfactory. The contrast between the screen and its surroundings must be adequate according to the type of activity and viewing requirements of the user.
- Glare, reflex and reflections on the screen or any reflective surface must be avoided by arranging the objects in the work area according to the arrangement and technical properties of the artificial light sources.
Unfavourable lamp positioning can lead to direct or reflected glare, which can impair vision. In order to minimise reflected glare, surfaces of workplaces should be matte. In addition, building services engineers should take into account directed light and the effects of shadows when choosing a lighting scheme. At a workstation where a right-handed person is working, the light should fall onto the work surface from the left side and vice versa otherwise shadows could impair perception.
Colour rendering is another important factor wherever high quality lighting is required such as an office environment. This refers to the accuracy with which a light source shows the true tone of a colour or range of colours. The new European standard (EN 12464-1) for a workplaces states that: “Lamps with a colour rendering index of Ra <80 should not be used in rooms in which people work or stay for lengthy periods."
Lumilux lamps from Osram already meet these requirements with a De Luxe version available that provides a colour rendering index of Ra >90. This means that illuminated objects, materials and surfaces appear in their natural colours ensuring improved perception and comfort to the eye.
A lighting scheme that creates ‘good light’ is defined as much by its energy efficiency as it is by the lamps used to create an optimum lighting ambience. In the current climate, there is increasing pressure placed on building services engineers to reduce a building’s energy wastage and carbon emissions as this subsequently leads to lower energy bills.
Although energy efficient lamps are initially more expensive to purchase, they pay for themselves within one year due to their reduced energy consumption. Energy saving compact fluorescent lamps use 80% less electricity than a standard incandescent lamp while providing the same light output. In addition, these energy efficient lamps now have a lifespan of up to 15 years meaning they need to be replaced less often, which reduces maintenance costs.
With the requirement for all buildings to own and display an Energy Performance Certificate, it is imperative that building services engineers take advantage of energy efficient lighting. Retrofitting energy efficient lamps in place of traditional incandescent lamps is the simplest way to make a significant impact on lowering energy consumption as well as reducing CO2 emissions.
We have a far better understanding now about the capability that light has to impact an environment – whether it be an office, a corridor, or a break-out room. It is essential that a lighting scheme compliments the functionality of a space. Combining this knowledge with rapidly evolving lighting technology, we are well-equipped with the knowledge, expertise and products to create exemplar lighting installations.
When it comes to the design and installation of a lighting scheme, building services engineers will often need to reconcile conflicting requirements to create a high quality lighting system that translates into lower energy bills and reduced CO2 emissions.
By taking into account lamp types and their potential energy savings and colour rendering, as well as the potential for glare and shadows in the area to be lit, those responsible for specifying the lighting scheme in a workplace will be best placed to achieve the optimum lighting conditions.