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Lighting Survey

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  rev. 2011-07-04        


The lighting survey itemizes the existing equipment room-by-room.  The fields are as follows:


Floor/Zone (optional)

Used to sort records by building zone.  If this field is not used, the records will be sorted by room number.

Room (required)

Room number or designation.


Pick from the drop-down pick list.  Lighting tasks are used by designers to determine light level requirements and allow you to compare existing light levels to IESNA standards.


Number of fixtures in the room


Electrical supply voltage


Fixture type, including the housing, lens, and reflector.  There are many codes, following a consistent naming convention.


Days per week, used to calculate annual operating hours.


Weeks per year for calculating annual operating hours.  Annual Operating Hours = Wk/Yr * Day/W * Hr/Day.  Where there is partial use on weekends some adjustment to hours and days may have to be made to ensure that this calculation works out correctly.


Demand Factor.  This is a value used to lighting scientists to indicate the probability that particular lights will be on when the monthly peak electrical demand is set.  A factor of "1" means that there is 100% certainty that the light fixtures will be on during the demand peak.  Monthly demand peak occurs somewhere around 1pm or 2pm for most commercial buildings and around 6pm or 7pm for most residential buildings.  Fixtures located in areas with occupancy sensing might have a lower probability (say 0.5 or 50%) of contributing to the demand peak.  Outdoor security lights that come on only at night would have a 0% change of contributing to the demand peak.  ManagingEnergy uses the demand factor to calculate overall lighting electrical demand and to estimate demand savings from retrofits.


Ballast Type for all fluorescent and HID lighting technologies. noballast  is indicated for regular incandescent fixtures.  Note that transformers for LED and low-voltage halogen technologies are selected here even though they are not ballasts by strict definition.  The naming convention will help you interpret ballast type codes.


Ballast Quantity per fixture.  This is not the total number of ballasts in this lighting record, but is the number of ballasts in each fixture.  Normally this number will be 1, but it may 2 or 3 for multi-tube fluorescent fixtures.  It may also be 0.5 for tandem fixtures where a single ballasts serves lamps in two fixtures.


Lamp Type.  The naming convention will help you interpret lamp type codes.


Lamp Quantity per fixture.  This is the total number of lamps in each fixture, not the total number of lamps in this lighting record.


Lamps Used per fixture.  This is the number of lamps actually energized in each fixture.  Normally it will be equal to L-Qty, but could be less, where many lamps have been intentionally disconnected or the lighting system is poorly maintained and a significant percentage of lamps are burned out.  Note that ManagingEnergy calculates ballast losses for all ballasts in a fixture, but calculates lamp consumption only for the number of lamps used.

Lighting Redesign Fields

There are six fields dealing with light levels and room dimensions.  Five of them are needed only where lighting redesign is part of the project.  There is significantly more work required for ceiling plan redesigns, so many ManagingEnergy projects restrict the lighting analysis to fixture technology upgrades (i.e. one for one fixture replacements or modifications, or perhaps simple one for two replacements).  For those projects, only the Task light level may be collected and entered, to give the analyst information on whether the space is overlit or underlit.

Min Level

Minimum measured light level (in foot-candles or lux, depending on the measurement system being used).

Task Level

Light level measured at task height (on desk, table, drawing board…).  This information should always be collected and entered.

Max Level

Maximum measured light level.


Length of room (in feet or metres, depending on the measurement system).


Width of room.


Height of room.


A place to put other important information not covered by the other fields.

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