Frequently Asked Questions

A lighting design is a technical study that shows, through calculations and drawings, which luminaires are installed where, in what quantity and wattage, and what illuminance, uniformity and glare each area will achieve with that layout.

It is recommended for new buildings and refurbishments, LED retrofits of existing lighting, when energy consumption needs to be reduced, when users complain about eye strain or glare, and when compliance with standards has to be documented.

Architectural drawings (preferably DWG or PDF), ceiling height and type, the use of each area, interior colours and materials if available, and the desired colour temperature and controls. Without drawings we can start from dimensions.

EN 12464-1 for indoor workplaces, EN 1838 for emergency lighting and EN 13201 for road lighting. The target illuminance, uniformity and glare for each area are taken from these standards.

An illuminance calculation report per area, the luminaire layout on the architectural plan, a luminaire schedule with technical data, and an installed power and energy consumption summary.

With the lumen method: number of luminaires = (target lux × area) ÷ (luminaire lumens × utilisation factor × maintenance factor). The result is rounded to a regular grid and verified with software.

It expresses the geometry of the space in one number: k = (length × width) ÷ (mounting height × (length + width)). The utilisation factor is read from the luminaire's photometric table according to this value and the surface reflectances.

About 0.8 is usually used in clean environments; in dusty and dirty environments lower values are used, depending on how often the luminaires are cleaned.

For the same illuminance the installed power usually falls clearly; in the hall of the worked example, installed power drops to about one third compared with the 400 W metal halide solution.

The architectural plan (DWG or PDF), ceiling height and type, the use of each area, surface colours and materials. If there is no plan, you can start with a dimensioned sketch.

A preliminary sizing method that calculates the total luminous flux needed to achieve the target illuminance in an area: number of luminaires = (target lux × area) ÷ (luminaire lumens × utilisation factor × maintenance factor).

The lumen method gives an average value. Software uses the luminaire's real light distribution (photometric file) to calculate the illuminance, uniformity and glare at every point, showing corners that stay dark or spots that cause glare.

A coefficient that takes into account that illuminance will fall as the luminaire gets dirty and the LED loses light over time. It is usually about 0.8 in clean interiors and lower in dusty environments.

For each product: a datasheet, an LM-79 report showing system lumens, LM-80/TM-21 data for LED lifetime, EN 60598 safety and EN 55015 EMC test reports, and a CE declaration of conformity.

Project-specific adaptation of wattage, size, colour and optics is faster; spare parts and drivers are easy to obtain, and production can be seen on site with a factory visit.

Five years is a common expectation in commercial projects; ask in writing under which operating conditions (temperature, operating hours) the warranty applies.

It is a great advantage in projects; at the very least the manufacturer should be able to supply photometric files (IES/LDT) for its products so that calculations can be made.

Quality industrial LED luminaires reach 130–160 lm/W and premium office luminaires 120–140 lm/W. 80–100 lm/W is budget-product level. The value is calculated by dividing the system lumens in the luminaire's LM-79 report by its total power.

At least 0.90 in commercial and industrial projects. In sensitive applications such as offices, hotels and hospitals 0.95 is targeted, and 0.98 or higher in large facilities.

L70 is the time after which the luminaire's light output falls to 70% of its initial value; B50 means that half of the luminaires of the same model have reached this point. A claim of "L70B50 @ 50,000 hours" is only meaningful when supported by LM-80 measurements and a TM-21 calculation.

No. CE is a declaration of conformity signed by the manufacturer itself. For real assurance, EN 60598 (luminaire safety) and EN 55015 (EMC) test reports should be requested, and marks from independent bodies such as ENEC, VDE or TÜV should be verified with the certificate number.

LEDs do not fail suddenly; they lose light over time. 50,000 hours usually refers to the time after which light output falls to 70% of its initial value (L70). For a luminaire running 10 hours a day, this is about 13.7 years.

The LED chip converts part of its energy into heat, which builds up at the junction of the chip. As the temperature rises, light output falls and lifetime shortens; that is why quality luminaires use aluminium heat sinks to keep the junction temperature below 85°C.

It converts the alternating current of the mains into the constant direct current the LED needs, keeps the brightness stable and protects the chip from overcurrent. The lifetime of a luminaire often depends on the quality of the driver before that of the LED.

In general office use the difference is limited. Where colours matter, such as skin tones, food, textiles and artworks, CRI 90+ light shows colours clearly more vivid and natural.

R9 measures how accurately the saturated red test colour is shown and is not included in the standard CRI average. So two luminaires with CRI 90 can have very different R9 values; in projects where meat, wood and skin tones matter, "CRI > 90, R9 > 50" should be specified together.

No. Colour temperature (Kelvin) describes whether light looks warm or cool; CRI describes how accurately it shows colours. A 2700K light can have CRI 95, and a 6500K light can have CRI 70.

The spectral power distribution of the light source is measured with a spectrometer, and the appearance of test colours R1–R8 is compared with their appearance under a reference light. Extended measurements also include colours R9–R15.

A 60 W incandescent bulb gives about 800 lumens. With an LED of 100 lm/W efficacy, the same light is obtained at about 8 W; depending on the product's efficacy, the value varies between 7 and 10 W.

Consumption (kWh) = total power (kW) × operating time (hours). For example, if 50 luminaires of 20 W (1 kW) run for 10 hours a day on 22 days a month, monthly consumption is 220 kWh.

Usually yes within the same product family. When comparing different products, however, the deciding factors are lumens and lm/W, not watts; an efficient low-wattage luminaire can be brighter than an inefficient high-wattage one.

Warm white light of 2700K–3000K and, if possible, a dimmer are recommended. Warm tones do not suppress melatonin production and make it easier to fall asleep; cool white light should be avoided in the hours before bed.

Neutral to cool white light of 4000K–5000K suits tasks that need attention; it supports concentration and shows colours clearly.

4000K is neutral white. It is neither as warm as yellowish light nor as cool as 6500K daylight, which is why it is often chosen for kitchens, bathrooms and multi-purpose spaces.

A technology that lets one luminaire emit light at different colour temperatures, usually between 2700K and 6500K. It is the basis of human-centric lighting, which changes the light during the day in line with the natural daylight cycle.

It depends on the product: 2700K–3000K with CRI 90+ in clothing stores, 4000K–5000K in electronics stores, and in jewellery 2700K–3000K for gold and 4000K–5000K for diamonds and platinum.

They can, but a difference of more than 500K within the same visual scene causes eye strain. Transitions between different zones such as lobbies and corridors should be designed gradually.

Yes. Cool tones create contrast and clarity and make a space feel larger; warm tones create an intimate, smaller-feeling atmosphere.

Both are completely dust-tight. IP65 withstands low-pressure water jets; IP67 withstands immersion at a depth of 1 metre for 30 minutes. IP67 should be chosen for ground and recessed applications where water can collect.

At least IP44 should be used in bathrooms. Higher protection should be chosen close to the shower and bath, where water splashes directly.

IP shows protection against dust and water; IK (IEC 62262) shows resistance to mechanical impact. IK10 means resistance to an impact of 20 joules; in schools, sports halls and public areas both values should be checked together.

Dust and water tests are carried out to IEC 60529 in an accredited laboratory. Look at the test report rather than the manufacturer's declaration and, if possible, at approval from an independent body such as VDE or TÜV.

Gold looks richer and more yellow under warm white light of 2700K–3000K. White gold, diamonds and silver look brighter and cleaner under neutral or cool white of 4000K–5000K.

A diamond's sparkle comes from point-source light. Narrow-beam spotlights from a single point are used instead of widely diffused light; crystal or lensed optics increase the sparkle.

At least Ra 90 is recommended. A high R9 value, which represents red, is also an advantage for showing stones and gold in their true colours.

LEDs emit much less heat than halogen and metal halide lamps and almost no UV, so they do not heat the product inside the display and reduce heat build-up on the display glass.

As it is a place to rest, warm white of 2700K–3000K is preferred. At the bathroom mirror, 3000K–4000K high-CRI light that shows the face accurately suits make-up and shaving.

No. With motion sensors or time programmes, the light can be dimmed to a low level at night and raised when someone passes; emergency lighting and escape signage must always remain operational.

With DALI each luminaire is addressed individually; day, evening and night scenes in the lobby, integration with key-card energy systems in rooms and central fault monitoring become possible.

Wallwashers and narrow-beam luminaires that emphasise the architecture are used on the façade, with a brighter area welcoming guests at the entrance. Outdoor luminaires should be at least IP65.

According to EN 12464-1, the typical target for parking areas and driving lanes is 75 lx. At entry and exit ramps, 300 lx by day (so the eye can adapt from daylight) and 75 lx at night are recommended; 300 lx is targeted at ticket and payment points.

In indoor car parks at least IP65 is recommended because of dust, humidity and floor washing. In open car parks, pole-mounted luminaires should be IP66–IP67 against rain and dust.

Most car parks are empty for most of the day. When motion-sensor luminaires dim to 10–30% while nobody is there and go to full power when a vehicle or pedestrian is detected, energy consumption falls clearly compared with a system running at full power all the time; the ratio depends on usage.

Indoor car parks usually use neutral to cool white of 4000K–5000K for alertness and visibility; Ra 80 luminaires are sufficient for distinguishing colours.

On single-phase track all spotlights are fed from one circuit and switch on and off together. On three-phase track the spotlights can be connected to three separate circuits via their adaptors, so different groups on the same track can be controlled separately.

A narrow 12°–20° beam to accent a single product or painting, a medium beam of about 34° for shelves and displays, and a wide 44°–60° beam to light larger areas.

It depends on the ceiling height, target illuminance and beam angle. For window and shelf accents under ceilings of about 3 metres, 20–30 W models are preferred; for high ceilings and wide beams, 30–40 W and above. The exact value is determined by calculation.

It reduces glare by preventing a direct view of the light source; it is particularly recommended at angles close to the customer's eye level.

Surface-mounted (directly on the ceiling), recessed (into a suspended ceiling) and pendant (on suspension wires). Pendant models can emit light downwards only (direct) or both downwards and onto the ceiling (direct/indirect).

An opal diffuser spreads light softly and evenly and hides the LED dots. A micro-prismatic diffuser directs light in a controlled way and lowers glare (UGR); it suits office areas with screens.

Yes. With systems such as Line-Set, luminaires are joined to create a continuous line of light along a corridor or open-plan office; feed points are planned at the design stage.

Because part of the light is reflected from the ceiling, the ceiling does not stay dark, the space looks more open and glare is reduced; they are preferred in open-plan offices and meeting rooms.

A downlight is usually wide-beam and fixed, for general lighting. A recessed spotlight can have a narrower beam and is often adjustable; it is used for accent lighting.

The cut-out size is given in each model's datasheet. The ceiling hole is cut to this size; there must be enough depth in the ceiling void for the luminaire body and driver.

As a starting point, a spacing close to the ceiling height is taken (for example, wide-beam downlights at about 1.2–1.5 m intervals under a 2.8 m ceiling); the spacing is verified by calculation according to the beam angle for uniform light.

Models with at least IP44 protection; higher protection is preferred close to the shower.

24 V is preferred for long runs: it draws a lower current for the same power, so voltage drop is reduced and there is less loss of brightness at the end of the run. 12 V is sufficient for short applications.

An aluminium profile dissipates the strip's heat and extends its life, while the diffuser hides the LED dots and creates an even line of light.

Multiply the strip's power per metre by the total length and add a margin of about 20 percent. For example, 10 metres of 14 W/m strip = 140 W; a driver of at least about 170 W is chosen.

Enough distance must be left between the strip and the ceiling for the light to spread across it; very narrow gaps create a sharp, patchy line on the ceiling. The dimension is set in the installation drawings according to the cornice or plasterboard detail.

Usually 3000K–4000K; in mosques with historic stone and timber surfaces, warm 2700K–3000K tones show the texture better.

Yes. The appearance of the existing chandeliers can be retained while converting to LED at lamp-holder and lamp level; the colour temperature and brightness should be the same throughout the chandelier.

With linear or narrow-beam luminaires concealed at the base of the dome, showing the painted decoration evenly and without glare; the light sources are hidden from the congregation's view.

Daily prayers, Friday prayers, Eid, Tarawih and cleaning need different light levels; scenes save energy and make the attendant's work easier.

Analyses the requirements, sets target values according to the standards, carries out the illuminance calculation, selects luminaires and the control system, prepares energy and cost comparisons and supervises the installation.

It is recommended. Replacing old luminaires one-for-one with the same number of LED luminaires often gives either more light and energy than necessary or uneven illuminance. With measurement and calculation, a better result can be achieved with fewer luminaires.

A calculation report for each area, a luminaire layout plan, a luminaire list and technical specification, a summary of installed power and energy consumption and, where needed, control scenes.

The typical target for general lighting in the sales area is 300 lux, with 500 lux at the checkout. Accented products and shelves are given 3 to 5 times this value.

Recessed downlights or linear luminaires for general lighting, adjustable track spotlights for product and shelf accents, narrow-beam spotlights in the window and concealed LED strip inside shelves.

Usually 3000K–3500K, a warm tone that does not distort product colours. CRI 90 or higher is essential for products to look right.

An average of 500 lux is targeted at desks. Typical values are 750 lux for fine work such as technical drawing, 200 lux in archives and 100 lux in corridors.

UGR (Unified Glare Rating) is the degree of glare from luminaires; the lower the value, the less glare. For screen work in offices the upper limit is 19.

Usually 4000K neutral white; it supports concentration and shows colours naturally. 3000K can be preferred in break areas.

High-efficacy (lm/W) luminaires, daylight sensors near windows, presence sensors in meeting rooms and toilets, and dimming via DALI are the most effective methods.

It depends on the precision of the work: about 300 lux for rough assembly, 500 lux for medium, 750 lux for fine assembly and 1000 lux for precision work. 100 lux is typical in warehouses and storage areas.

IP20–IP40 may be enough in dry, clean production areas; IP65 is recommended in dusty environments and IP66–IP67 in areas with pressure washing.

High-flux industrial luminaires with narrow or medium light distribution; in racking aisles, models with a long, narrow distribution that spreads light along the aisle are preferred.

If the accented object receives 3 times more light than its surroundings (3:1), the accent is noticeable; 5 times (5:1) gives a strong focus and 10 times or more (10:1) a dramatic effect. If the surroundings are at 100 lux, 500 lux on the object is targeted for a 5:1 accent.

Track spotlights in shops and exhibitions that need flexibility, adjustable recessed spotlights in minimal ceilings, wallwashers on textured walls, and miniature spotlights with 8°–12° beams for small objects such as jewellery displays.

8°–15° for small objects, about 24° for medium-sized surfaces such as paintings and shelves, and 36° or more for larger areas.

CRI 90 or higher is required for objects where colour matters, such as artworks, textiles and food. If red tones are important, an R9 value of at least 50 should also be written into the specification.

A DALI line supports 64 addresses; each luminaire can be controlled individually or in groups, and up to 16 scenes can be stored in each luminaire. Larger projects use several lines and gateways.

1-10V is a one-way analogue signal; all luminaires on the line dim to the same level and no fault information is returned. DALI is digital and two-way; each luminaire is addressed separately, and information such as operating hours and driver faults can be monitored centrally.

Yes. The most common architecture is a hybrid in which KNX manages all building systems and DALI controls the luminaires precisely. The two systems are connected with KNX-DALI gateways.

No. A DALI line can be laid in star, branch or mixed topology without regard to polarity; two extra cores added to the supply cable are usually enough.

Luminous flux (lumen) and efficacy (lm/W), colour temperature, CRI (80 in offices, 90 and above in shops), beam angle, glare in offices (UGR below 19) and compatibility with the dimming system (1-10V, DALI, Triac) should be assessed together.

Low-glare (UGR < 19) linear, recessed or surface-mounted luminaires, 4000K colour temperature and at least CRI 80 are recommended. According to EN 12464-1, 500 lux is targeted in work areas used for writing and reading.

Luminaires with at least IP44 protection should be chosen for damp areas. Check the IP rating on the product pages.

A recessed spotlight is built into the suspended ceiling and sits flush with it. A surface-mounted spotlight is mounted directly on surfaces without a ceiling void.

Each product page gives the cut-out diameter; the ceiling hole is cut to this size. Also check that there is enough depth in the ceiling for the luminaire and driver.

Yes, models with IP44 or higher can be used in damp areas such as bathrooms.

When there is no suspended ceiling, the ceiling void is insufficient, or the luminaire is meant to be a visible design element.

Yes. Flu 90-85, Madame 85-150 and Pollux 60-100 are also available as pendant versions with the same housing.

Above dining and meeting tables the luminaire is usually positioned 70–90 cm above the table surface, so the light is focused on the table without dazzling the people seated.

Pendant models are mounted with suspension wires; the length is adjusted to the ceiling height during installation.

The spotlight adapter must be compatible with the track system (single-phase or three-phase). Tell us your track type and we will quote with the right adapter.

A narrow beam (about 15°–24°) to accent a single product or display, a wide beam (36° and above) to light shelves and larger areas.

CRI 90 and above is recommended so that product colours look right; for textiles and food also ask for the R9 value.

An LED panel emits light from a square or rectangular surface. A linear luminaire forms a slim, long line; it can follow architectural lines and be joined end to end to form continuous lines of light.

In work areas with screens, choose models with low-glare diffusers and a glare rating (UGR) below 19.

The choice depends on the size of the area and the target illuminance. Longer, more powerful models light larger areas with fewer luminaires; the right quantity and layout are determined with a DIALux calculation.

For projects that need a continuous line of light, the Line-Set system is used.

Line length is planned per project; total power and feed points are calculated at the design stage.

For projects requiring corners and special shapes, the decorative linear series (such as L-Line, Cross Line and Quadra Line) can be considered.

Yes, with the right wattage and layout they provide general lighting. The wattage and luminous flux options of each model are in the datasheet on the product page.

The size and wattage options of each model are on the product page and in its datasheet. Contact us for custom sizes for your project.

24 V is preferred for long runs: it draws less current for the same power, so voltage drop is lower and there is less loss of brightness at the end of the run. 12 V is sufficient for short applications.

Yes, this is recommended. The aluminium profile dissipates the heat of the strip, extending its life, and its diffuser removes visible dots for an even line of light.

In production areas requiring attention and precision, 4000K–5000K neutral to cool white light supports operator alertness.

If the internal components are not protected in areas with dust, humidity and washing, lifetime is reduced. Choose IP65 and above in such areas and IP66–IP67 where washing takes place.

The required illuminance depends on the precision of the work; the number and layout of luminaires are calculated with DIALux based on ceiling height and the layout plan.

Uniform wallwashing on flat, large surfaces, grazing light on textured surfaces such as stone and brick, and narrow-beam accents on elements such as columns and domes.

Warm 2700K–3000K tones for stone, brick and historic fabric; 4000K can be preferred for modern façades dominated by glass and metal. Coloured (RGB) effects are planned as scenes for special occasions.

As in-ground or wall-base luminaires at the foot of the surface, linear luminaires under the eaves, or floodlights on an opposite building or pole; the choice depends on the angle of incidence of the light and the texture of the façade.

Asymmetric optics direct the light only onto the surface, anti-glare accessories are added to the luminaires, and programmed dimming or switching off is applied late at night.

A wallwasher stands at a certain distance from the wall and lights the surface evenly; a grazing luminaire stands very close to the wall and skims light across the surface, emphasising texture and shadows.

As a general starting value, at about one third of the wall height; the exact distance and luminaire spacing are determined by calculation according to the luminaire's light distribution.

Yes. Lighting the walls in lobbies, galleries, shops and meeting rooms makes the space look more open; outdoors they are used for façade lighting.

IP20 may be enough indoors; on exterior façades at least IP65, and IP67 for in-ground models.

At least IP65 is recommended for standard outdoor applications exposed to rain. IP67 should be chosen for in-ground installations or places where water can collect.

Astrodim means the LED driver automatically dims the light at pre-programmed times during the night. Power is reduced after midnight when traffic decreases, saving energy without an extra control cable.

An aluminium housing, electrostatic powder coating against corrosion and a UV-resistant optical lens are basic requirements for a long life outdoors.

Spacing depends on the light distribution of the bollard and the required illuminance of the path; we recommend calculating it at the design stage for an even light level.

Because it is exposed to rain and dust, at least IP65 is recommended; IP67 should be preferred where ground water can collect.

Road lighting is calculated to EN 13201, taking into account the road class, traffic density and width; pole spacing and luminaire wattage are determined by this calculation.

Savings depend on the hours and the level of dimming during the night. Reducing power when traffic decreases lowers energy consumption without additional wiring.

Zapata, Zapata T, Zapata Y and Zapata X are available in different wattage ranges; lower wattages suit narrow site roads and higher wattages wide roads. The wattage and lumen values of each model are in its datasheet.

At least 1 hour for escape lighting; an operating time of 3 hours is required in high-risk areas such as factories, hospitals and residential blocks.

The most reliable sign is that the battery cannot complete the required duration in the annual full-discharge test. Typical lifetimes are 4–6 years for NiCd, 3–5 years for NiMH and 8–10 years or more for LiFePO4 batteries.

Yes. Every test and battery replacement should be entered in the logbook; buildings without records may face sanctions during inspections. Systems with automatic test modules keep this record themselves.

At least 1 hour for escape lighting; 3 hours are required in high-risk areas such as factories, hospitals and residential blocks.

An emergency kit is a module installed in an existing LED luminaire that keeps it lit from a battery during a power failure. An emergency luminaire is a separate luminaire that operates independently with its own battery.

A short functional test, a monthly test and an annual full-discharge test measuring the real battery capacity should be carried out, and the results recorded in the logbook.

The output power and voltage range of the kit must match the LED load of the luminaire. Choose the model according to the LED voltage of the luminaire and the required emergency duration; if in doubt, ask our technical team.

Duration depends on the battery capacity of the kit and the power it delivers in emergency mode. At least 1 hour is targeted for evacuation and 3 hours in high-risk areas.

A battery that cannot complete the required duration in the annual full-discharge test should be replaced. Battery life depends on its chemistry; LiFePO4 batteries last longer than NiCd and NiMH batteries.

A maintained luminaire is also lit in normal operation and continues on battery during a power failure. A non-maintained luminaire only switches on when the mains fails.

It should switch on within a few seconds of a mains failure; at least 1 lux must be provided on the centre line of escape routes.

Above emergency exit doors, at corridor turns, at the top of stairs and at intervals that ensure at least one sign is visible from every point of the escape route.

Exit signs are usually operated in maintained mode so that the escape route can be read at any time.

Choose a battery with the same type, voltage and capacity as the battery of the existing kit or luminaire. If in doubt, send us the kit model.

If the emergency lighting cannot complete the required duration in the annual full-discharge test, the battery should be replaced.