Andrea Barausse is the founder and managing director of Durban-based lighting company Energywise Systems. In 2023, he was elected as the technical chair of IESSA – the Illumination Engineering Society of South Africa.
In the world of lighting, the role of temperature in performance often lingers in the wings, overshadowed by other factors such as cost. This oversight becomes particularly significant when we consider the international standards that dictate that luminaires be tested at a temperature of 25°C, a benchmark that may not accurately mirror real-world conditions, especially here in Africa’s harsh climate.
South Africa, characterised by a climatic range of 15-36°C in summer, presents a unique challenge for the lighting industry. On a normal summer day, many indoor industrial applications see temperatures soar well beyond 45°C, especially at elevated ceiling heights that trap heat and where lighting fixtures are commonly positioned in a factory or warehouse environment.
The crucial parameters for luminaires – including lumen output, temperature behaviour (L&B) and Driver F ratings – are calculated for an ambient temperature (Ta) of 25°C. As a rule of thumb, for every 10°C above this threshold, the performance of electronic components within luminaires is anticipated to be as much as halved. This correlation between operating temperature and component longevity directly influences Return on Investment (ROI) calculations, making it a pivotal factor for businesses and consumers alike.
Given the high temperatures experienced in most industrial settings, this prompts us to question whether testing standards should evolve to reflect more realistic conditions. Should we not then be testing luminaires for a Ta of 35°C or even higher to ensure accuracy in our performance expectations? Or are South Africans expected to install air-conditioning systems in our warehouses and factories to achieve the results promised to us on the promotional material?
Understanding the impact of temperature on lighting performance is not merely an academic exercise but rather a practical consideration with tangible consequences. The industry’s current reliance on a standardised testing temperature can and does lead to miscalculations in lifespan or performance expectations and, consequently, hinder accurate ROI projections. And if we cannot influence the testing standard as we would like, then surely our lighting designs should account for the realities that our fixtures have to function in. How would this occur, you ask? Typically by throttling down the milliamps pumping through the luminaire and dropping its lumen output. However, this sees you needing to install more lights to get the same result as originally required. Far from ideal, but that is the non-sugar-coated reality that we are facing. And if you are not, you should be asking questions of those specifying your lights.
As an industry, we have two options as I see it: A paradigm shift that insists the African temperatures be used as a standard for light fittings used in South Africa (crazy I know) resulting in more robust lights that are task-specific, or (and more immediately achievable) an insistence by you, the consumer, that demands temperature be considered in your solutions.
