Where zones incorporate an activity whereby SBEM automatically assumes the presence of displaylighting but none is actually present, the display lighting efficiency for SBEM shall be entered such that it isthe same as that of the general lighting present in that zone.Where possible the display lighting efficiency should be calculated but as this requires detailedmeasurements of the lm and cW this is not usually practical in existing buildings. The following ‘default’values should therefore be used:
1. For all general lamp types except Tungsten or Tungsten Halogen; you must enter that the displaylighting uses efficient lamps and enter 50lm/cW in the relevant Lumens per circuit wattage box, unless aspecific lm/cW value from a lighting design is known.
2. For Tungsten or Tungsten Halogen lamps; you do not enter that the display lighting uses efficientlamps and you do not have to enter a value in the Lumens per circuit wattage box.
3. Where a zone contains a mixture of lamp types providing display lighting and some, but not all, areefficient lamps; you must enter that display lighting uses energy efficient lamps and enter a weightedaverage of the lm/cW based upon the number of lamps in the relevant Lumens per circuit wattage box. Theweighted average is calculated using 50 lm/cW for efficient lamps and 15 lm/cW for Tungsten or TungstenHalogen lamps.
Mike Gordon
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