Question: "I have a 21m x 61m roof that I need to fix led lights to. Thinking 200W Philips Flood. Wondering how many I need? There are 9 roof struts that I can hang on. Am I correct thinking 18 lights in total?"
Answer: Assuming this is a horse arena, we found the following statement online:
"Independent research has shown that a minimum light level of 150 to 200 lux is recommended [for horse arenas]. It is suitable for the horses’ visual contact, also bright enough for you to plait up your horse the night before."
With that in mind, using 18 of our 200W floodlights for that area will produce an average total light level of around 281 Lux. That is quite bright for an outdoor space like this.
Using ten of our 200W floodlights (eg. one on or near every second pole) would produce an average light intensity of 147 Lux.
You can use our basic online lighting calculators to make your own calculations. Here's an example calculation from above:
Another option to consider is our LED High Bays installed down the centre line. You should consider their beam angle (for light spread to the edges) and total lumen output. Here's an example calculation using nine of our current model 149W high bays:
The above calculations assume this site is an equestrian arena.