Useful information about lighting

Accent & presentation Lighting - Office

Presentation areas, images and objects require supplementary lighting. Accent lighting � as well as playing a functional role � has an impact on room atmosphere. One of the prime requirements for effective accentuating light is a graduated lighting level: the level of the accent lighting needs to be significantly higher than that of the ambient lighting.

For shelving systems where reading tasks are performed or where space is used for displays, recommended solutions include asymmetrical wallwashers or downlights with fluorescent or halogen lamps. These deliver the vertical illuminance needed to ensure that the entire surface is uniformly illuminated from top to bottom. Alternatives are spots mounted on or in the ceiling or on a wire or rod system. They can be individually positioned and angled as required. Some spots also offer the possibility of varying the way they distribute light. Where objects are displayed behind glass, a high-quality anti-reflective coating is advisable.

Mounted on arms of different lengths and with swivellable reflectors for flexible arrangements, spots on power track are also an attractive alternative to fixed picture lights because they can easily be adjusted to cater for changing presentations. For picture lighting, the colour rendering properties of lamps is an important factor; a colour rendering index of Ra ≥ 80 is a must. Where pictures are exposed to lighting for prolonged periods, the problem of colours fading can be reduced by UV barrier filters.

Where lighting is installed inside cabinets, the heat generated by lamps needs to be dissipated outside. This is particularly important for heat-sensitive exhibits, for which the best lighting options are LED or fibre-optic systems. Important safety note: where luminaires are mounted directly on wood, they need to display not only the VDE, ENEC or GS symbol but also the M fire safety symbol. It is also important to ensure that luminaires are not positioned at less than the minimum permissible distance away from illuminated objects.

Accent lighting-Cafeteria,Restaurant

Whether the design statement is minimalist chic or sumptuous intimacy � accent and decorative lighting adds life and lustre to a room. Accent lighting derives its dynamism from differences in illuminance, playing with stark contrasts and hard-edged shadows, varying brightness and light incidence, weaving a spell with colours and contours.

Accent lighting directs the eye of the observer � to architectural features, pictures and sculptures, special exhibits or an appetizing buffet. To achieve maximum impact, it needs to create pools of light significantly brighter than the lighting level provided by the general lighting. Safelight filters and reflectors prevent sensitive materials and foods being exposed to harmful rays or heat.

The range of accent lighting options is wide: for large pools of light, swivel-mounted downlights or wide-angled spots, e.g. fitted with metal halide lamps, are a suitable solution. Asymmetrical wallwashers guarantee shadow-free illumination even for high rows of shelves and presentation areas. Spots casting highly focused beams of brilliant halogen light lend a sparkle to glass and porcelain.

Accent lighting emphasizes the architecture of a room: spots above or luminaires set into the floor cast pillars in a dramatic light, back-lit glass walls draw the eye of the observer, recessed light sources and fibre-optic systems structure arches and walls. Coloured and dynamic lighting, special effects such as gobo images and alternating colours, turn the room and its peripheral zones into a stage set.

Accent lighting- Dining Room

Apart from serving a functional purpose, lighting also impacts on the atmosphere of a room. To achieve a homely lighting atmosphere, it is essential to ensure that illuminance is not always the same throughout the room, i.e. that not all the luminaires in the room are always on at the same time and that the lighting can be dimmed. Accent lighting, e.g. for pictures or display cabinets, provides visual relief.

Spots mounted on wire and rod systems or power track can easily by angled and directed; unlike fixed spots, they provide a flexible solution which enables pictures or sculptures to be repositioned and spotlighted again in their new location. Dedicated picture lights are available for illuminating pictures.

Display cabinet and shelving unit lighting sets attractive accents. Individual sections can be illuminated by ceiling-mounted spots or luminaires which are either recessed in the furniture or mounted on clamps. It is important to note, however, that recessed luminaires for mounting on a wooden substrate need to display not only the VDE, ENEC or GS symbol but also the M symbol. In the case of spots and clamp luminaires, care must be taken to observe the minimum permissible distance from the illuminated surface.

A wall or section of wall free of furniture - whether it is bare or hung with decorations - becomes an eye-catching feature when bathed in the light of downlights mounted on the wall in a row. Away from windows, accent lighting can also be provided by plant luminaires.

A particularly harmonious atmosphere is generated by the interaction of direct and indirect lighting. Indirect light reflected into the room by walls and ceiling is found visually agreeable. Ceiling floods (also uplights) are well suited to this task. As standard luminaires, they can normally be used singly; as wall luminaires, they should be used in multiples.

Today, there is a wide choice of luminaires designed to radiate most of their light upwards for indirect lighting and cast the rest of their light downwards for direct lighting. Another practical solution is the dual-purpose standard luminaire, in which a ceiling flood provides mostly indirect lighting for general illumination and a second luminaire beneath the flood provides direct lighting for reading at about the height of a person seated.

Important note! Indirect lighting alone can result in poor modelling and a monotonous atmosphere. For strenuous visual tasks, such as reading, writing or handiwork, direct lighting is always the better choice.

Accent lighting Garden

Illuminated vegetation makes for a magical lighting atmosphere. Colourful flower beds, interesting foliage, even objets d'art retain their eye-catching appeal in artificial lighting.

Artificial lighting gives the garden at night a special visual impact, forming structures that uniform daylight cannot create. The atmosphere generated is particularly striking where vegetation is assigned its own supplementary lighting. Flowerbeds, shrubbery, bushes, groups of trees - they can all be accentuated to good effect, usually by spots or floods mounted on or in the gound. Mobile spots have the advantage that they can be re-positioned to set new accents, e.g. as the seasons change.

It is advisable to position light sources at varying distances from the objects they illuminate. It is also important to plan transitions from light to dark, because dark zones are essentail for effective highlighting.

Accent lighting Hall and corridor

The atmosphere of any room is enlivened by accentuating light - and entrance halls are no exception. Narrow beams of light for selective spotlighting and/or wide-angled floods for the planar illumination of pictures or wall sections have the desired effect. Other accent lighting options are picture lights and illuminated showcases and shelving systems.

Illuminated walls and a dark ceiling impact considerably on spatial impression, making a high-ceilinged room look lower. Conversely, to make a low entrance hall look higher, the answer is to provide a large number of points of light - e.g. recessed downlights - on the ceiling. Incidentally, long narrow halls look shorter when lit by elongated luminaires or lighting systems mounted crossways and the spatial impression made by very small halls can be altered for the better by round luminaires.

Accent lighting-Home office

A desk-top luminaire should never be the only luminaire switched on. This is because where surroundings are relatively dark, its light causes reflections on the monitor screen, giving rise to disturbing reflected glare. Also, when our eyes switch back and forth between a bright screen and a dark room, they have considerable difficulty adapting. The correct solution is largely uniform brightness, which calls for at least one more luminaire to be switched on.

Supplementary accent lighting is also good. Illuminated pictures or light in a shelving system or display cabinet enliven the atmosphere of a room. Where low-voltage tungsten-halogen lamps are used, they should be wide-angled (flood) models. Narrow-angled (spot) lamps tend to create sharp light/dark contrasts or cause reflected glare on screens. Like all luminaires in the room, spots on a wire and rod system or power track need to be angled so they do not cause reflected glare.

Accent lighting -Living room

Apart from serving a functional purpose, lighting also impacts on the atmosphere of a room. To achieve a homely lighting atmosphere, it is essential to ensure that illuminance is not always the same throughout the room, i.e. that not all the luminaires in the room are always on at the same time and that the lighting can be dimmed. Accent lighting, e.g. for pictures or display cabinets, provides visual relief.

Spots mounted on wire and rod systems or power track can easily by angled and directed; unlike fixed spots, they provide a flexible solution which enables pictures or sculptures to be repositioned and spotlighted again in their new location. Dedicated picture lights are available for illuminating pictures.

Display cabinet and shelving unit lighting sets attractive accents. Individual sections can be illuminated by ceiling-mounted spots or luminaires which are either recessed in the furniture or mounted on clamps. It is important to note, however, that recessed luminaires for mounting on a wooden substrate need to display not only the VDE, ENEC or GS symbol but also the M symbol. In the case of spots and clamp luminaires, care must be taken to observe the minimum permissible distance from the illuminated surface.

A wall or section of wall free of furniture - whether it is bare or hung with decorations - becomes an eye-catching feature when bathed in the light of downlights mounted on the wall in a row. Away from windows, accent lighting can also be provided by plant luminaires.

A particularly harmonious atmosphere is generated by the interaction of direct and indirect lighting. Indirect light reflected into the room by walls and ceiling is found visually agreeable. Ceiling floods (also uplights) are well suited to this task. As standard luminaires, they can normally be used singly; as wall luminaires, they should be used in multiples.

Today, there is a wide choice of luminaires designed to radiate most of their light upwards for indirect lighting and cast the rest of their light downwards for direct lighting. Another practical solution is the dual-purpose standard luminaire, in which a ceiling flood provides mostly indirect lighting for general illumination and a second luminaire beneath the flood provides direct lighting for reading at about the height of a person seated.

Important note! Indirect lighting alone can result in poor modelling and a monotonous atmosphere. For strenuous visual tasks, such as reading, writing or handiwork, direct lighting is always the better choice.

Accent lighting - Sales room

The purpose of accent lighting is always to direct the observer's eye to the merchandise, whether it is presented on racks, stands or shelves or in showcases or displays. So, lighting for vertical surfaces is important and flexibility is a priority.

Accent lighting derives its vitality from different illuminance levels. It plays with contrast and shadow, varies brightness and light incidence, weaves a spell with colours and contours. "Display light� and �decorative light� enhance product appeal. Dramatically lit displays are popular today even in supermarkets. Suitable light sources include wide-angle spots fitted with metal halide lamps. The lighting needs to set off the structure, texture and colour of the merchandise on display to best advantage. Damage to sensitive materials and foods can be prevented by safelight filters and reflectors.

For stands and shelves, wide-angle spots or swivel-mounted narrow-beam downlights are the right choice. Also recommended are continuous rows of luminaires for fluorescent lamps, either suspended from the ceiling or mounted on shelving units. Asymmetrical beam floodlights guarantee shadow-free lighting even for high rows of shelves.

Peripheral zone lighting also has a major impact on the ambience and architecture of a salesroom. Peripheral zones are highlighted and brought to life by dynamic lighting and special effects such as gobo images and changing colours

Accent lighting - Shop Window

The secret of a successful window display lies in the artistry of its presentation. This lives from the dramatic interplay of light and shadow, from dynamism and change. And artificial lighting can play a crucial role here: the capacity for variable control of different accents and effects � different light colours, moving lights with or without motifs, changing colours and patterns � makes lighting a very important tool for the window designer.

Light cast in variously shaped beams and from various angles enhances gleaming highlights and lends emphasis to contours. The visual impact of jewellery can be underlined by light colour: warm-white light � the right choice for most shop windows � brings out gold tones in particular; neutral-white metal halide lamps are a good choice for underlining the cool appeal of silver.

Light sources for shop windows need to combine high luminous efficacy with very good colour rendering. Suitable options include tungsten halogen lamps for low-voltage or mains-voltage operation, metal halide lamps and high-pressure sodium vapour lamps. New kinds of "lighting production" are made possible by fibre-optic lighting systems and LEDs.

Balcony Lighting- and patiop

For balconies, wall luminaires are often the best solution for a stationary lighting system. Where a balcony is roofed, recessed ceiling luminaires or surface-mounted ceiling luminaires are an alternative or supplementary option. Mobile spots and luminaires on earth spikes are well-suited for use in planters and windowboxes; on small balconies, there is normally no need for anything other than this mobile lighting.

Balconies are not very deep constructions, so spots and windows are not far apart. Because of this proximity, there is a risk of glare from reflections in the glass. Consequently, care needs to be taken to ensure that spots are appropriately angled and positioned.

Bays more than 6 metres high

Factory bays over six metres high require powerful but economical lamps: 250 Watt to 1,000 Watt metal halide or high-pressure sodium vapour lamps cast enough light from high ceilings to ensure adequate illuminance at the working plane. High-bay prismatic diffuser or high-bay specular reflector luminaires have an axially symmetrical and narrow-angled intensity distribution curve. Where high vertical illuminance is required for inclined surfaces, additional luminaires for three-band fluorescent lamps need to be used.

Metal halide lamps are economical light sources combining compact design, high luminous flux, very high luminous efficacy and good colour rendering properties with a long service life. High-pressure sodium vapour lamps also have a high luminous flux rating, achieve somewhat higher luminous efficacy and are available in colour rendering index Ra = 80 - 89, 60 - 69 and 20 - 39.

Bedside lighting -Bedroom

Bedside lighting is provided by a table luminaire on a bedside table or wall luminaires mounted beside or over the bed. These luminaires need to ensure glare-free lighting and should feature a rotatable and swivellable reflector as well as an adjustable arm to enable them to be positioned to meet individual requirements. Soft diffuse lighting is found agreeable. Lamps with a narrow beam spread are thus unsuitable.

For double beds, it makes sense to wire bedside luminaires for separate switching and dimming. A partner who goes to sleep earlier is thus less likely to be disturbed. Light switches at beds should be within easy reach. Two-way and multi-circuit switches permitting all other separately switchable luminaires to be operated from the bed are a convenient and practical solution.

Anti-burglary systems enable exterior lighting to be activated from a single point inside the home in the event of suspicious noises being heard near the house. Installing the central switch near the bed permits the fastest possible response.

Bedside lighting -Child's or Teenager' Room

A bedside luminaire is not just appreciated by adults: for youngsters, it provides comforting light, reading light and light for banishing the darkness after a bad dream. To permit flexible positioning - especially to prevent glare - stationary wall luminaires or table luminaires for the beside table should be fited with rotatable and swivellable reflectors as well as a movable arm. Diffuse soft lighting is found agreeable, so lamps with a narrow beam angle should not be used.

Where wall luminaires cannot be installed and where there is no bedside table, as in the case of most high beds, a clamp luminaire is the alternative - although only for older children who no longer use the bed as a romping ground. Failing that, an additional switch for the ceiling light can be installed near the bed.

Children find it pleasant to have a dim light in the room so that if they wake up suddenly in the night they can see they are in familiar surroundings. Pilot luminaires and nightlights for electric sockets are suitable for this. They consume very little power. The electricity bill for using a 0.3 Watt nightlight every night for a month amounts to only coppers.

Blackboard lighting -Classroom

The blackboard needs to be clearly visible from every desk and anything written on it easy to read. This calls for uniform distribution of brightness over the entire surface of the board, including any hinged or sliding extensions. It also requires high vertical illuminance, which additionally prevents reflections � images of bright windows or luminaires � on the board.

Both tasks are performed by supplementary lighting. This can be provided by recessed ceiling and surface-mounted ceiling luminaires or pendant luminaires in wallwashing designs (asymmetrical beam) or wide-angle spots, e.g. on power track. The light sources are mounted parallel to the board across its full width. It is important to ensure that the luminaires cast light only in the direction of the board; spots should be well shielded on the side facing the class. Installing this supplementary lighting on a separate switching circuit enables it to be used as required and saves energy costs.

Changing cubicle lighting -Salesroom

Changing cubicles are a place where decisions are made, where we make up our mind whether to buy something or not. Bright cheerful lighting and very good colour rendering are important. Unflattering shadows are undesirable, so directional light is not recommended. Sometimes, if enough light enters the cubicle, the general store lighting may be enough. Supplementary lighting should always be provided at the mirror, however. The correct solution here: luminaires to the right and left of the mirror radiating soft light in the cubicle or light sources mounted behind the mirror.

For the ultimate in comfort and convenience, changing cubicle lighting can be programmed to create a variety of lighting scenes: dimmed warm-white light for evening wear, daylight-grade lighting for a business suit. At the push of a button, the lighting atmosphere can be changed.

Changing table and play table lighting -Child's or Teenager's Room

Parents generally stand at the changing top with their back to the ceiling light, their shadow falling onto the surface where the baby is lying. So general lighting in a nursery needs to be supplemented by task lighting even when the child is an infant. Suitable options for the changing top are wall luminaires or - where no wall outlet is available - a clamp luminaire with a flexible arm. Because infants are very sensitive to light, indirect lighting is recommended. This requirement is met by wall luminaires where the light exits upwards or clamp luminaires positioned for uplighting.

When babies start to crawl, nothing seems safe from their grasping fingers; they investigate everything they come across. So there can be no question of positioning luminaires within a young child's reach. Not even those decorative nursery lights in housings shaped like cartoon characters. They may use lamps with low power ratings but they still operate on 230 volts! What's more, youngsters need to learn that lamps generating light get hot, especially incandescent lamps, tungsten-halogen lamps and low-voltage tungsten-halogen lamps.

For the nursery table, pendant luminaires or sturdy desk luminaires are the right choice. Filigree feature lights suspended from wire and rod systems should be used with caution: they too invite investigation by an inquisitive youngster.

Communal changing room lighting -changing room

In large, communal changing rooms, a uniform lighting level is important. DIN EN 12193 requires only 100 lux illuminance here but a minimum of 300 lux is more comfortable. The higher lighting level makes items in lockers or sports bags easier to find, for example. It also makes for a greater sense of security and avoids any impression of lack of cleanliness.

Three-band fluorescent lamps (26 mm or 16 mm diameter) operated by electronic ballasts (EBs) are particularly recommended as an economical lighting solution for communal changing rooms. More energy savings can be made with motion detectors for controlled, presence-dependent lighting.

Accent lighting makes for a less clinical lighting atmosphere, heightening visual comfort and enhancing the impression made by the changing room and the sports facility. Wall luminaires are a suitable solution here.

Communication area lighting -Trade fair stand

For eye-catching appeal, a trade fair stand needs to make a visual impact from a distance. A bright, inviting appearance is achieved with stand lighting which ensures adequately high levels of vertical illuminance. Where this is not achievable with the accent lighting alone, additional luminaires or spots should be used, e.g. to brighten walls.

For communication zones, freedom from glare and a uniform level of lighting are primary design requirements. Here, the first issue that needs to be decided is whether to opt for direct or direct/indirect lighting. Surface-mounted or recessed ceiling luminaires for tubular three-band fluorescent lamps or for compact fluorescent lamps are the correct choice. Owing to the low ceilings found on most trade fair stands, suspended ceiling luminaires are rarely an option. Alternatives - also for use in combination with other luminaires - are downlights with wide-angled beam characteristics.

Lamps with low heat radiation ratings are recommended. As well as those listed, low-voltage tungsten halogen lamps with cool-beam reflectors are a good choice. Accentuating light in communication zones can be provided by wallwashing downlights, for example, or display-lighting spots on consulting room walls.

Conference table lighting -Office

At conference tables, lighting works in the background. Attention here is focused on the persons seated at the table. Preferred luminaires are pendant or standard luminaires for direct/indirect lighting. Producing soft lighting that makes for balanced modelling and an agreeable atmosphere, they ensure that faces appear natural and documents are clearly legible. Glare from non-shielded luminaires or disturbing reflections on shiny desktops need to be avoided. The correct light colour for lamps is neutral white or warm white.

Important note! Marked brightness contrasts need to be avoided at meetings or conferences. They cause fatigue and affect concentration. Modern lighting management systems are a convenient tool for tailoring lighting to requirements. At the push of a button, for example, conference table lighting can be supplemented by subdued general lighting or wallwashing light highlighting pictures or presentations.

Conference zone lighting -Library

Conference zones are provided in a library to enable groups to discuss the information they gather. Often, these areas are walled off from the rest of the library so the sound of conversation does not disturb users who are reading.

Like workplace lighting, conference zone lighting needs to meet high lighting requirements. DIN EN 12464-1 stipulates 500 lux illuminance. As an alternative to pendant luminaires with linear three-band fluorescent lamps, mobile direct/indirect standard luminaires are an option here. They distribute light in the room and at the same time illuminate the ceiling, setting accents and thus making for an agreeable atmosphere.

Conference zone lighting -Staff room

The conference zone of a staff room forms an integral part of the whole concept. As in the rest of the room, direct/indirect luminaires are also recommended here � e.g. pendant luminaires or standard luminaires. Correct illuminance: 500 lux. For presentations with overhead or computer projectors, however, lighting in this part of the room should be separately switched and dimmable.

Conventional operating theatre -Operating theatre

The visual task in the operating field calls for such high illuminance � 10,000 to 160,000 lux - that problems of adaptation can occur for surgical team members switching their gaze to other parts of the room, which are comparatively dark. For the general lighting here, DIN EN 12464-1 stipulates 1,000 lux. To facilitate adaptation, a mean illuminance of 2,000 lux is recommended for the immediate surroundings, which are defined as an area approximately 3 x 3 metres centred on the operating table.

The ceiling luminaires of the surround lighting need to be clustered as tightly as possible around the operating table. This avoids glare and prevents shadows being cast by the surgical team.

Corridor lighting -Corridor's and staircases

Corridors require good, uniform lighting so that visitors can find their way quickly and efficiently. To prevent unwanted "tunnel effects" in extended corridors, however, care must be taken to avoid a uniform, monotonous lighting level. It is better to offer the human eye variety by incorporating different levels of brightness into the lighting design.

Illuminated walls make a corridor look wider; indirect light bounced off the ceiling makes it look more open and welcoming. In long corridors, it is also recommended that luminaires should be set at right angles to the direction of movement. This makes the corridor look shorter. A wide variety of luminaires are available for corridor lighting. Options include, for example, downlights, wall luminaires, recessed and surface-mounted ceiling luminaires, and suspended luminaires for direct or direct/indirect lighting. Accents can also be set with recessed floor luminaires, which emphasize the course of the corridor.

According to DIN EN 12464-1, corridor lighting should provide at least 100 lux illuminance (maintenance value). Where the lighting level in adjacent rooms exceeds 1,000 lux, illuminance in the corridor needs to be scaled up. To enable the human eye to adapt easily to the transition from brighter to darker conditions, illuminance in the corridor needs to be at least ten percent of the illuminance in neighbouring rooms.

As a general rule, corridor lighting remains in operation for long periods, so power consumption is correspondingly high. The energy balance is improved by fluorescent lamps or compact fluorescent lamps with plug-in base for electronic ballast (EB) operation. It is also a good idea to wire the lighting for switching in stages: in a retirement home at night, for example, 50 lux is enough to facilitate adaptation between corridor and room, whereas at least 100 lux is needed during the day. Lighting management systems offer convenience and economy � for shops and office buildings as well. Lighting levels can thus be tailored to suit individual requirements: one level for day-time, another for cleaning operations and a third for at night.

Wallwashing raises the level of vertical illuminance and makes for greater visual comfort. Signs and guidance aids are highlighted by accent lighting, for which downlights, wall luminaires and a variety of spots are suitable. Where low-voltage tungsten halogen lamps are used, they should have a wide beam spread (wide flood) because highly focused light can cause glare.

Important note: for safety in buildings, escape routes need to be clearly identified and serviced by appropriate emergency lighting.

Counter and cashier's desk lighting -Cafetaria and resturand

Special attention needs to be paid to lighting at buffets and food counters because they are places where difficult visual tasks are performed. The brightness of the lighting needs to be twice as high as that of the surroundings and luminaires need to be well shielded. A higher level of brightness makes for better orientation; first-class colour rendering, successful use of accentuating light and gleaming effects on glass and porcelain ensure an eye-catching presentation.

Counter lighting should make work easier for personnel and should also be attractive - requirements which are both met, for example, by small directional, dimmable spots for low-voltage tungsten halogen lamps with cool beam reflectors. They highlight food without exposing it to radiant heat. To ensure that food looks fresh and appetizing, good colour rendering (Ra index ≥ 80) is essential. The light colour of the lamps used should be warm white (ww) or neutral white (nw).

Cashier's desks are workplaces: displays need to be reflection-free, number pads brightly enough lit � 300 lux minimum.

Cycle path lighting -Cycle path

At a distance of 10 metres, the illuminance of a cycle headlamp is 0.5 lux; at a distance of 20 metres, it is around 0.15 lux. Its light is enough to see the area immediately in front of the bicycle but it leaves the surroundings in darkness: away from lit streets, oncoming traffic or anything approaching the cycle path from the side can only be identified if the cycle path has its own lighting. For lighting cycle paths set back from main roads (min. 15 lux where the distance is 8 metres or more), on unlit roads (min. 3 lux), outside built-up areas and in parks or gardens (min. 1.5 lux), luminaires with reflectors for extremely wide-angled intensity distribution are required. They create uniform lighting conditions with relatively wide - and therefore economical - luminaire spacing.

Desk lighting -Child's or Teenager's Room

Homework is hard work - but it is easier when adequate light is available for reading and writing. The correct solution is a desk luminaire designed for flexible directional adjustment. It should cast bright uniform light over the entire desktop. Where the light comes from the left for right-handers and from the right for left-handers, the writing hand does not cast disturbing shadows.

Where a computer is used, the visual task is more demanding. Reflections on screen and keyboard are particularly disturbing but they can be avoided by ensuring that monitor and luminaires are properly positioned in relation to one another. Under no circumstances should all the luminaires in the room be switched off because switching our gaze back and forth between a bright screen and dark surroundings overtaxes our eyes.

Parents who realise their offspring are computer freaks can opt at an early stage for luminaires designed for VDU workplaces in offices. These include numerous models which by no means look out of place in the home. Compact or three-band fluorescent lamps in these luminaires should deliver a warm-white light.

Where indirect lighting is preferred, suspended luminaires such as those used for professional VDU workplaces are the right choice. Uplights are also an option for the home computer desk. Comfortable versatile lighting is most easily achieved where each luminaire is separately switched and dimmable.

Dining table lighting -Conservatory

For the best dining table lighting, luminaries hould be selected to suit the size and design of the tables. Round or oval, square or rectangular - there is a wide variety of luminaires available for any shape of table. Also possible is an arrangement of several small luminaires mirroring the shape of the table, e.g. a circular group over a round dining surface. For long tables, a row of pendant luminaires is a recommended option.

Pendant luminaries - are a good solution for this lighting task - a flexible solution if they are designed for variable height adjustment.The positioning of the luminarie(s), their design and the way they distribute light should be determined by the table top. Other possibilities are wire and rod systems or power track with luminaires suspended over the table. The ideal dining table luminaire - around 60 centimetres above the table - illuminates the table top and the surrounding area without causing glare. Supplementary lighting provided by standard luminaries, wall luminaries or table luminaries is not only nice to look at; it also improves perception of the room as a whole.Separately switched luminaires and dimmable lighting enable the lighting atmosphere to be adjusted to suit a particular visual task or occasion.

Where a pull-out table is extended to full length, the normal table lighting is generally no longer enough. This problem is solved by wire and rod or power track systems: designed to suit the table when it is fully extended, they enable additional luminaires spots from elsewhere in the lighting system to be positioned over the table whenever they are needed.

The brilliant warm-white light of standard-voltage or low-voltage tungsten halogen lamps is a popular choice. Alternatives, apart from ordinary tungsten filament lamps, are energy-saving lamps or compact fluorescent lamps (light colour: warm white). These lamps all have very good color rendering properties.

Pendant luminairies

The classical rise-and-fall solution is a springloaded pendant luminariewith spiral cable (1): the luminaire is suspended from a thin wire rope running down the centre of a helical cable establishing the electrical connection. When the luminaire is raised, a spring in the ceiling rose winds up the wire rope.

In the case of the telescopic tube system (2), a clamping device holds the luminaire at the required height. The spare power cable lies loose in the ceiling rose.

The luminaire can also be fixed by screw fasteners (3): the mobile luminaire mounting bracket runs up and down two fixed guide rods.

Other easy-to-use systems rely on counterweights. (4 to 6). Pulling the weight down raises the luminaire (4), lifting it lowers the luminaire housing. Alternatively, the cable can be wound round pulleys (5 and 6): the lower pulley is connected to a weight, which holds the luminaires at the required height.

Doctors room lighting -Doctos and nurses Room

Doctors rooms are predominantly used as offices, so their lighting needs are defined mainly by VDU work. Important requirements are uniform, low-shadow light distribution and at least 500 lux mean illuminance as defined in DIN EN 12464-1. Care must always be taken to ensure freedom from glare: unshielded lamps and bright surfaces reflected on monitors can cause direct and reflected glare.

Direct/indirect lighting is generally the option of choice because it has the effect of illuminating the ceiling, which is found particularly agreeable. Pendant luminaires or standard luminaires combined with individually switched task luminaires are suitable for this lighting task. Luminaires for fluorescent or compact fluorescent lamps � especially in conjunction with electronic ballasts (EB) � are an economical option.

Where a doctors room has communication zones and doubles as a rest room, supplementary accent lighting is recommended. The accentuating light can be provided, for example, by wall luminaires fitted with tungsten halogen lamps � ideally on separate switching circuits and dimmer-controlled.

Where a room is also used for examinations, the lighting needs to meet the requirements for examination and treatment rooms.

Entrance and exit lighting -Indoor car park

At entrances and exits, differences in brightness call for adaptation zones to help our eyes adjust to the change in visual conditions. It can take several hazardous minutes for the human eye to adapt to darkness. Adaptation to brightness, however, takes only seconds. So the greatest challenge to the adaptive capacity of our eyes is encountered when we drive into an underground car park on a sunny day. 300 lx is the correct horizontal illuminance for the adaptation zone of a comparatively dark underground car park. Where adaptation conditions are less extreme - mostly in multi-storey car parks - 100 lx is enough. Adaptation conditions are also positively influenced, for example, by high and wide entrances. At night, 75 lx is sufficient for vehicle entrance and exit zones.

To make ticket machines easier to operate, it is recommended that the lighting level at barriers should be close to the day-time lighting level of the entire entrance and exit zone.

Entrance lighting -Entrence and foyer

The entrance is the link between outdoor and indoor areas of a building. It is where visitors move from lighter to darker surroundings, or vice versa, and need to adjust to the difference in brightness (adaptation). It is thus a good idea to create an adaptation zone at the door: during the day, the entrance needs to be brightly or very brightly lit, depending on the level of available daylight; at night, the illuminance in the building should decrease in the direction of the exit. A daylight-dependent lighting control system is recommended for this.

Steps and stairs which structure the entrance area or lead deeper into the building require special attention. Where lighting is correct, treads are clearly distinguished from one another by short, soft shadows. Extra security is offered by orientation luminaires mounted on the wall flanking stairs or integrated into risers. Modern LED lighting strips and recessed wall luminaires are suitable solutions for orientation lighting.

Entrance lighting -Tunnel

The most demanding visual task in a tunnel is driving into it during the day: the difference in visual conditions between daylight outside and a comparatively dark tunnel entrance requires intense visual concentration. Where no artificial lighting is provided or where lighting is poor, the entrance of an approaching tunnel looks like a black hole. That impression is dispelled by a high lighting level, which should be lowered only gradually over the entrance zone and a transition zone beyond it.

Our eyes have far fewer difficulties adapting from darker to brighter conditions (adaptation), so entering a brightly lit tunnel at night presents no real problems. Entrance zone luminance can be adjusted to take account of fluctuating levels of daylight by lighting control systems with luminance sensors.

Escape route lighting -Emergency lighting

Safety lighting for escape routes is required for various types of premises: production plants and administrative buildings, department stores and hotels, assembly halls and indoor car-parks are examples. It needs to create adequate visual conditions for finding and following escape routes within the building and to help ensure reliable access to emergency equipment. Escape and rescue route plans need to be displayed where they can be consulted by both the building's users and rescue teams.

Escape sign luminaires (back-lit signs) or illuminated safety signs displaying white symbols on a green background are used to point the way to the nearest exit. Where DIN VDE 0108 requires permanently maintained lighting, the luminaires or signs must be designed or illuminated for a higher mean luminance of 200 cd/m² to ensure that they are also clearly discernible when the general lighting is (still) in operation. For emergency operation, the standard stipulates that the luminance of the green background should be more than 2 cd/m².

Escape route lighting is provided by mains-independent emergency luminaires. One important consideration here is glare limitation, because where few light sources are used in relatively dark rooms, the risk of glare is particularly acute. In halls used for events attended by large numbers of people, anti-panic lighting may also be needed to help ensure that escape routes are reached.

Escape signs -Emergency lighting

Luminescent signs, even high-performance luminescent signs, are no substitute for emergency lighting. Luminescent markings on or near the floor can at best be used to supplement emergency lighting. This is because no luminescent coating can provide illumination. The only way to ensure safety on escape routes is by using luminaires. There are several reasons for this:

Luminescent signs require lengthy exposure to adequate light prior to an emergency. Luminaires, on the other hand, are not dependent on the operating condition of the general lighting system.

The perceived brightness of luminescent signs decreases very rapidly, so the safety colour green quickly becomes hard to make out. The luminance of luminaires, however, remains constant all the time they are in operation.

Because visual acuity and perceptibility decline as luminance decreases, luminescent signs have a diminishing recognition range. Luminaires, however, are clearly discernible at all times.

The pictures show the difference. An escape sign luminaire (right) in a maintained lighting situation (white contrast colour luminance: 400 cd/m²) and in emergency operation (25 cd/m²), a luminescent sign immediately after exposure to excitation light (40 cd/m²) and 10 minutes after power failure (0,027 cd/m²).

More information on this subject can be obtained from the ZVEI Emergency Lighting Working Group and its members.

Examination and treatment lighting -Ward

A higher lighting level is required at the patient's bedside for medical and nursing procedures. Depending on the type of procedure performed, DIN EN 124640 stipulates 300 lux illuminance for simple and 1,000 lux for more complex examinations and treatments. This lighting level can be achieved using all the lighting facilities in the room. What is important to ensure is that doctors and nursing staff are not dazzled by the lighting.