Wall reluctance & lighting level

m sleem

Senior Member
I?m in a hospital project where I?m the consultant supervisor, currently & as per the lighting design the lighting calculation was performed based on the default wall reflectance by the software (Dialux) =50 while the actual wall reflectance based on the architectural design =min 83, because of the difference in wall reflectance & based on the architectural design can reduce the number of the designed lighting fixtures by min 30% in many areas, I have all the powers to change/reduce the no of the lights based on the designed wall reflectance but my fear is perhaps the wall reflectance might be changed while interior works. Absolutely going for wall reflectance =50 is more safer, what do you think?


Senior Member
New England
I'd say it depends how likely the wall reflectance levels will change. If they've painted the interior walls I don't see why it would go down, unless they repaint everything. I also suspect changing the model from 50 to 83 will not impact the light levels a ton. Taking out 30% of the fixtures sounds like overkill, but re-running the model would help nail that down.


Senior Member
Electrician ,contractor
Is this standard practice in the area where you work to require the lighting to take in account the surrounding reflectance.
Is that a ASHRE standard?