ERCO planning data Example
Clean room with little deterioration Annual cleaning of the luminaire Improvement of the room reflectance factor every 3 years, e.g. by cleaning the room surfaces Lamp replacement after 10,000 hours Immediate replacement in case of lamp failure
LMF Luminaire Maintenance Factor
Cleaning frequency (a) Ambient conditions Closed-top reflectors
1 2 3 P C N D P C N D P C N D 0.94 0.89 0.81 0.72 0.88 0.80 0.69 0.59 0.84 0.74 0.61 0.52
RSMF Room Surface Maintenance Factor
Cleaning frequency (a) Ambient conditions Direct emission
1 2 3 P C N D P C N D P C N D 0.99 0.98 0.96 0.95 0.97 0.96 0.95 0.94 0.96 0.96 0.95 0.94
LLMF Lamp Lumen Maintenance Factor
Hours of operation (h) Compact fluorescent lamps
2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 -- -- -- -- -0.92 0.88 0.85 0.83 0.85
LSF Lamp Survival Factor
LSF = 1
If all the individual maintenance factors are known, these can simply be inserted into the formula. Where individual parameters change, the maintenance factor must be recalculated.
Luminaire Maintenance Factor MF = LMF · RSMF · LLMF · LSF MF = 0.94 · 0.96 · 0.85 · 1 MF = 0.76
New value of the lighting installation
En = Em / MF En = 500lx / 0.76 En = 652
The reference maintenance factors
In cases where the maintenance factor cannot be calculated on the basis of definite assumptions, the following reference maintenance factors are recommended:
Reference Reference maintenance new value factor factor
Example
0.80 1.25
Clean room, little use
0.67 1.50
Clean room, 3-year maintenance cycle
0.57 1.75
Interior and exterior, average conditions, 3-year maintenance cycle
0.50 2.00
Interior and exterior, severe deterioration, 3-year maintenance cycle
ERCO Program 2013
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