Welcome to the first in a series of blogs from Glowled where we answer questions from NEPIC members on LED lighting.
𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻: 𝗪𝗲 𝗮𝗿𝗲 𝗮𝗯𝗼𝘂𝘁 𝘁𝗼 𝗲𝗺𝗯𝗮𝗿𝗸 𝗼𝗻 𝗼𝘂𝗿 𝗹𝗶𝗴𝗵𝘁𝗶𝗻𝗴 𝗽𝗿𝗼𝗷𝗲𝗰𝘁 𝘄𝗵𝗮𝘁 𝗱𝗼 𝘄𝗲 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗸𝗻𝗼𝘄 𝘀𝗼 𝗼𝘂𝗿 𝗽𝗿𝗼𝗷𝗲𝗰𝘁 𝗶𝘀 𝘀𝘂𝗰𝗰𝗲𝘀𝘀𝗳𝘂𝗹?
A lighting retrofit, new build, or a facility expansion, is a unique opportunity to make a lasting impact.
If you are considering LED lighting, your decision will easily last for more than a decade, so it’s important that you take the time and effort to take a comprehensive approach to the project.
Before you start obtaining quotes for new lighting, there are important parameters of lighting that you should understand.
To assist you in comparing possible solutions for your lighting projects it is helpful to fully understand some of the terminology:
𝗟𝘂𝗺𝗲𝗻 (𝗹𝗺) is a measure of the visible light emitted by a source, and thus how bright a particular lamp or light source will appear. In simple terms, one lumen is equivalent to the light produced from a single common candle.
𝗪𝗮𝘁𝘁 (𝗪) is a measure of the power the light source will consume to produce the lumens stated. The wattage can give you a direct indication of the expected energy consumption of an electric lamp.
Additional energy will be consumed by power conditioning equipment situated between the mains supply and lamps.
Typically, this adds up to 10 percent to the wattage quoted on lamps. Suppliers often refer to this as ‘ballast’ or ‘induction’ power and will refer to ‘circuit’ or ‘system’ watts to mean the total power demand of the lighting unit.
𝗟𝘂𝗺𝗶𝗻𝗼𝘂𝘀 𝗲𝗳𝗳𝗶𝗰𝗮𝗰𝘆 is a measure of the efficiency of a light source and is expressed in lumens per watt (lm/W). Different types of lighting, such as compact fluorescent and light emitting diodes (LED) have quite different efficacies.
𝗟𝘂𝘅 is a measure of illuminance and is equivalent to lumens per square metre (lm/m2). It expresses the light falling on a surface and is a common design criterion.
The Chartered Institution of Building Services Engineers (CIBSE) produces a Guide for Industrial Lighting which gives lighting requirements for many application areas (for example, 150 lux for pump and compressor houses and 500 lux for a control room).
Illuminance greatly depends on the type of light fitting and the way it spreads the light on a surface. Watts per m2 per 100 lux is a good measure to compare different proposals as it takes into consideration all of the factors above.
𝗖𝗼𝗹𝗼𝘂𝗿 𝘁𝗲𝗺𝗽𝗲𝗿𝗮𝘁𝘂𝗿𝗲 is the colour of the light emitted by a lamp is either described (usually in terms of being cool or warm) or given with a measure in temperature in kelvin (K) – typically ranging from 1,000K to 6,600K.
The higher the temperature the colder the colour. For example, noon sunlight is a cool, blue light with a colour temperature of 5,600K and a traditional tungsten light bulb is a warmer light with a colour temperature of 2,800K.
𝗖𝗼𝗹𝗼𝘂𝗿 𝗿𝗲𝗻𝗱𝗲𝗿𝗶𝗻𝗴 𝗶𝗻𝗱𝗲𝘅 (𝗖𝗥𝗜) is a measure of how accurately a light source renders all frequencies of light, compared to a perfect white light source. It is rated on a range from 1 to 100. CRI is very important for sectors such as printing and textiles where a CRI of 90 or above is recommended.
𝗛𝘂𝗺𝗮𝗻 𝗽𝗲𝗿𝗰𝗲𝗽𝘁𝗶𝗼𝗻 𝗼𝗳 𝗟𝗶𝗴𝗵𝘁 and the surrounding environment are important factors. For example, 100 lux in a corridor with white steel-clad walls will be perceived as better lit than the same corridor with darker surface covering. The reflectance of these elements should be considered so you achieve the light level you need.
By familiarising yourself with these terms you will stand a better chance in comparing products suggested by lighting suppliers.
Make sure to look out for more articles coming soon and if you have a question please let us know!
And if you would like to discuss your current requirements and arrange a quotation for your project why not contact Rita Callender, Glowled’s Lighting Solutions Manager : firstname.lastname@example.org.
By Glowled Ltd