Modern Building Services

MODERN BUILDING SERVICES MARCH 2023 21 FEATURE WORKING BUILDINGS Thermal andweight considerations A product will have been designed for a specific technology’s weight and thermal characteristics. However, these aspects can significantly differ between LED replacement and fluorescent technologies. LED technology requires a method of heatsinking to remove heat as it does not naturally radiate heat in the same way as fluorescent lamps. The placement and operation of this heatsink can create localised heating within a luminaire as heat is not emitted across the entire surface of the lamp but only from the heatsink area. In addition, the local ambient temperature within a luminaire is designed to be at a level that is optimal for the technology it is designed for, typically 25°C for older fluorescent technologies and 35°C for T16 lamp sizes. Let’s be clear - it is not optimal for LED technologies. The heatsink itself can also add weight to the lamp. The lamp holders are specified based on a specific lamp weight and increasing this weight can result in them being insufficiently robust to hold the lamp, ultimately causing damage. Consider the users of the space LED Tubes don’t offer the same opportunity to make the lighting work for the users of the space. For example, they may not provide the same directional light output (often not meeting EN1264:1 2021 legislation) and therefore, will struggle to provide comfortable conditions for classrooms and offices. The photometric performance of a product, how efficiently it produces and distributes light, is based on the light source technology it was designed for. Therefore, when replacing fluorescent technology with LED replacement technology it should be checked whether the photometric performance is impaired, resulting in poor, non- uniform lighting or glare which can ultimately affect the experience of those using the space. Efficiency The efficiency of an LED product is generally declared for the complete luminaire. It is declared for the lamp for LED replacement lamps and therefore requires de-rating to account for thermal and optical losses when operated within the product. This must be correctly considered and accounted for expected efficiency savings to happen. Controls and emergency options On the theme of making the space work, LED tubes are usually non- dimmable and non-compatible with the existing control system (if in place) and generally do not offer emergency lighting compatibility. This could therefore require a new emergency lighting systemmeaning new wiring, fitting and labour costs which should be considered from the outset. If any product being retrofitted with LED lamps has an emergency lighting function, the correct operation of the new luminaire concerning the requirements given in EN 60598-2-22 and relevant application requirements, such as those presented in EN1838, will need to be verified. Remember, emergency lighting is a legal requirement to be fitted and operated correctly within a building. Will your warranty be intact? It’s difficult to give a yes or no at this stage, but let’s discuss the historical installation of a LED tube onto a ballast previously used with a fluorescent tube. When LED tubes were first launched, removing the ballast and starters in the existing fluorescent fittings was recommended. The ballast effectively reduces the long life of the LED tubes, and they are more likely to reach their expected life span of 30-50,000 hours if the ballast is removed. So here lies the other consideration: you now have an energy-efficient product. Still, of course, you should work with a qualified electrician to remove the ballast and rewire it to direct power. This naturally comes at a cost, and the warranty on the fitting from the manufacturer is now void. Today LED tube manufacturers are making electronic ballast- compatible LED tubes and providing starters to change out from the older ones. But the age of the existing ballast should be considered. If they have been operating for some time, you may have seen that the fluorescent tubes have been flickering and assumed the tube was the problem. Well, it could be that the ballast is failing due to power fluctuations, and this isn’t good for a fluorescent tube and certainly won’t be for a LED tube either. And to add to this point, if your existing ballast is failing and potentially damaging the LED Tubes, the warranty on the tubes is now void. Let’s also again consider the potential discolouration of any plastics and the area around the fitting, which we mentioned earlier. Suppose the product is altered, for example. In that case, rewiring to remove existing components from the electrical circuit, the safety tests become null and void, and any marking on the product, such as the UKCA/CE mark, should be removed, as well as the original manufacturer marking. Legally, the product must be retested and recertified in its new configuration to the relevant safety standards before it can be operated. Compliance with requirements cannot be assumed. Formal testing is required with documented results in the technical product file. Similarly, when using a different lamp technology, these lamps must be checked to ensure conformity with the EcoDesign and RoHS legal requirements. An additional implication of modifying the original luminaire is that any existing warranties will become invalid. So, in short, the likelihood is that the fitting has to be re-certified as all safety certification is void. It is effectively a new fitting. In conclusion When it comes to a quick, cost- effective replacement for T8/ T5 tubes, LED tubes seem like a quick win. But if you consider the above, is it your best option? Our team of experts can work with you to understand the space you’re looking to refurbish, the needs of the area and what needs to be achieved from an energy- saving point of view. We can work together to provide energy and cost savings, ease of installation and overall improve the experience of those using the space. More information can be found at www.zumtobel.com