Lighting FAQs
Explore straightforward answers to common questions about lighting, terminology and choosing the right solution.
Frequently Asked Questions
There are several types of lighting dimming, each offering different levels of control.
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DALI Dimming: Digital Addressable Lighting Interface (DALI) allows individual lights or groups of lights to be controlled through a digital lighting control system.
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DSI Dimming: Digital Serial Interface (DSI) uses digital signals to communicate between lighting controllers and compatible dimmable control gear.
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Switch Dimming: Uses a retractive (push-to-make) switch to adjust light levels through a simple mains-based control system.
Watts (W) measure the electrical power a lamp or luminaire uses. Traditionally, wattage was used to estimate brightness, but with modern LED lighting, lumens (lm) provide a more accurate measure of light output.
Energy consumption is also displayed on applicable lamp energy labels in kilowatt-hours per 1,000 hours (kWh/1000h). This helps you understand how much electricity a lamp uses over time.
Volts (V) measure electrical voltage, which is the force that drives electricity through a circuit. In lighting, the voltage rating indicates the electrical supply a lamp or luminaire is designed to operate with.
In the UK, the standard mains voltage is 230V, although the actual supply voltage can vary.
Lumens (lm) measure luminous flux, which is the total amount of visible light emitted by a light source. The higher the lumen value, the more light the source produces.
Lumens are also used to calculate luminous efficacy, measured in lumens per watt (lm/W). This shows how efficiently a light source converts electrical power into visible light. A higher lm/W value indicates greater efficiency.
TP(a) and TP(b) are fire performance classifications for thermoplastic materials used in lighting diffusers, particularly in ceiling panels.
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TP(a): Materials that meet stricter fire performance requirements, with no specific restrictions on diffuser size or spacing under the relevant classification.
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TP(b): Materials that meet a different fire performance standard but are subject to restrictions on diffuser size, coverage and spacing when installed in ceilings.
These classifications are covered by Approved Document B of the Building Regulations. Always check the relevant requirements when selecting luminaires for ceiling installations.
An IP (Ingress Protection) rating indicates how well a luminaire is protected against dust, solid objects and water.
The first digit represents protection against solid objects and dust, while the second represents protection against water. For example, an IP65-rated luminaire is dust-tight and protected against water jets.
Further information is shown below:
Ingress Rating |
Protection Rating |
|---|---|
|
0 - Not Protected |
0 - Not Protected |
| 1 - Protected against solid objects greater than 50mm | 1 - Protected against dripping water |
| 2 - Protected against solid objects greater than 12mm | 2 - Protected against dripping water when tilted up to 15° |
| 3 - Protected against solid objects greater than 2.5mm | 3 - Protected against spraying water |
| 4 - Protected against solid objects greater than 2.5mm | 4 - Protected against spraying water |
| 5 - Protected against solid objects greater than 1mm | 5 - Protected against water jets |
| 6 - Dust protected | 6 - Protected against heavy seas |
| 7 - Dust tight | 7 - Protected against the effects of immersion |
| 8 - Protected against submersion |
UGR (Unified Glare Rating) measures discomfort glare from artificial lighting. The lower the UGR value, the less glare is experienced.
UGR is calculated for a complete lighting installation rather than an individual luminaire. A UGR below 19 (UGR<19) is a common requirement for office lighting.
A lighting design is needed to confirm whether a space meets the required UGR level.
An IK rating measures how resistant a luminaire is to mechanical impact. The rating ranges from IK00 to IK10, with higher numbers indicating greater impact resistance.
For example, IK08 provides protection against impacts of 5 joules, while IK10 provides protection against impacts of 20 joules.
Return on Investment (ROI) measures how long it takes for the savings from a lighting installation to recover its initial cost. Factors such as energy efficiency, product lifespan and installation costs can all influence ROI.
BELL Lighting can help estimate potential energy and cost savings through our online Energy Saving Calculator or a more detailed assessment from our Sales Support Team.
For more information, contact your local Area Sales Representative or email sales@belllighting.co.uk.
Colour temperature describes how warm or cool the light emitted by a lamp or luminaire appears. It is measured in Kelvin (K).
Lower Kelvin values produce warmer, more yellow light, while higher values produce cooler, whiter light. Colour temperature refers to the appearance of the light, not the physical temperature of the lamp.
PIR (Passive Infrared) sensors detect movement by sensing changes in infrared radiation, typically caused by body heat.
Microwave sensors emit microwave signals and detect movement through changes in the signals reflected back from surrounding objects. Unlike PIR sensors, microwave sensors can also detect movement through certain materials.
BELL Lighting offers both sensor types across a range of lighting products, helping to provide automatic lighting control when movement is detected.
Need some help?
Our experienced team is here to help with your lighting requirements. Whether you need product information, project support or guidance on the right solution, we can point you in the right direction.
