# Light guides

If you’re looking for a place to start, a bit of guidance or simply some inspiration this is the place for you.

From offices, classrooms, warehouses and street to shopping centres, entrances and sports halls, click on the links below for our definitive guides for lighting numerous applications.

## Knowledge hub

### EN12464-1

The European standard for Workplace lighting. Find out all you need to know with detailed explanations and a flow chart for compliance.

### Design tips

Technical advice on energy efficiency and maintenance factors with a simply “visual evaluation” method and a glossary of terms.

### e-Learning

A series of short videos exploring some of the key issues in the lighting industry. A certificate is provided upon completion.

### LED lighting

The new normal of lighting. Here you can find information on efficiency, life-time, flicker, drivers, colour temperature and MacAdams.

### Light and health

Light, or light radiation, not only affects our visual cortex but also the whole of our alertness, wellbeing and performance.

### Q: How do I interpret the rated life of an LED luminaire?

A: The rated life of an LED is expressed via the L and B values followed by the time-period, as per the standard EN 62717. The L value indicated the percentage of the original output that will be produced within that time span. The B value related to the percentage ‘fraction’ within the same period. The term Failure rate is slightly misleading as the LEDs do not fail completely, they will still be producing light, but at a level less than what was specified. The L value is the most important indicator when it comes to planning light calculations as the B values are not incorporated at this stage.

Example:
L90 B10 50,000hrs = At 50,000hrs the luminaire will be producing 90% of the original output with 10% of the LEDs producing a lower level of light than what was specified.

### Q: Does using Constant Light Output affect the maintenance factor?

A: A luminaire with Constant Light Output (CLO) the L value is always 100%, or L100 , as the total output is regulated across the stated life. When calculating the Luminaire Maintenance Factor, the value for Lamp Lumen Maintenance Factor (LLMF) is 1.0. If the luminaire has a L70 value, for instance, the LLMF would be 0.7. In individual fittings the difference might not be that noticeable. Over a larger installation it would have a more significant impact.

### Q: How do I know what BIN’s my LEDs are from?

A: The LED modules are made up of diodes selected from three categories of BINs: Flux, Forward Voltage and Colour. The choice defines the cost, availability, efficiency and colour quality. While it is unusual for manufacturers to state the specific BINs on a product basis, if you want to ensure the right quality is being used, look for a good combination of output (LM), efficiency (lm/w) and colour consistency (SDCM), rather than one individual element.

### Q: What SDCM MacAdam should I specify for my project?

A: It depends on the application and what the luminaires will be illuminating. While the scale is quite small, the difference in colour consistency between 3 SDCM and 4 SDCM, for instance, is quite pronounced. As a rule, the minimum MacAdam requirements are outlined below:

• Macadam 2 SDCM: museum, gallery applications
• Macadam 3 SDCM: office, school, retail, healthcare applications
• Macadam 5 SDCM: outdoor applications

### Q: What is the difference CRI and TM30?

A: The difference is quite significant even if both are a measurement for the accuracy of reproducing colour. The Colour Rendering Index (CRI) is based upon the rendering of 8 different colours. TM30, however, is based upon 99 different colours and numerous different textures.

TM30 is a technical memorandum originating from the United States and has been adopted in a number of different countries worldwide. It is not currently the global norm and is not a standard and, according to CIE, within Europe CRI remains the approved method for stipulating colour reproduction.

### Q: Can you specify flicker free LEDs?

A: LEDs themselves don’t flicker, it related to the quality of the driver and the ‘ripple effect’ or the variation in the output current of the driver. Flicker is defined in four categories: Visible, Stroboscopic effect, Cameras and Barcode readers in shops. Using high quality drivers is the best approach to avoiding visible flicker with LEDs. With this approach you would usually experience 1-2% flicker, comparable to a T5 lamp with an electronic ballast.

### Q: Is there an alternative to 1-10v dimming with LEDs?

A: The main benefits of using a 1-10v dimming system is the simplicity and the ability to up-grade the lighting system using the incumbent wiring. There are increasingly less 1-10v drivers on the market, however there are interfaces from Tridonic that convert analogue to digital enabling you to use DSI protocol luminaires in an existing 1-10v system. If you are just interested in the rotary switch Osram offer a DALI rotary control panel MCU which you can connect any DALI fitting to.

### Q: What level of surge protection do I need?

A: For standard luminaires is in most areas a level of 6/8kV normally sufficient. In in areas with frequent thunderstorms a 10kV protection can be solved by adding an extra Surge Protection Device (SPD) between the luminaire terminal and the driver.

The safety requirements for luminaires are specified in the Europe standard EN60598-1 and relevant sub-standards and are mandatory. The standards state “over voltage protective devices which are external to control and connected to earth, shall be used only in fixed luminaires and connected only to a protective earth.” Within these requirement’s it is not permitted for a Class II luminaire with metal housing to have a SPD connected to that housing. The reason why it is prohibited for Class II is that the insulation distances are reduced and will not fulfil Class II requirements, therefore the luminaire can be unsafe. To ensure compliance with the standard a Class I luminaire should be used instead.