Hi, we have any questions about the desnsity lighting exterior:
1.- The building is located on a corner in one of the main streets of Mexico City, the architectural design has 23 terraces which will be illuminated on the front, through computerized LEDs that can change color. Could be seen as an icon or a commercial sign and enter the ASHRAE 90.1-2007 exceptions section 9.4.5?
2.- According to ASHRAE 90.1-2007 Section 9.4.5 The total external lighting power allowance for all Applications is building outside the sum of the single lighting power densities permitted in Table 9.4.5 for These Applications plus an additional unrestricted allowance of 5% of That sum. Trade-offs are allowed only among outdoor lighting Applications listed in the Table 9.4.5 "Tradable Surfaces" section. Does the total load on outdoor lighting can be considered as valid power increase by 5%?
3.- • According to Table 9.4.5 lighting power densities for building exteriors, we are looking for lighting of terraces a factor of 0.2 w / ft 2 (square areas), for our calculations of density are we right?
• According to Table 9.4.5 lighting power densities for building exteriors, we are looking for outdoor lighting of balconies in the vertical plane by a factor of 1.25 W/ft2 (canopies and overhangs), for our calculations of density are we in right?
4.- • According to ASHRAE 90.1-2007 Section 9.5.1 Building Area Method of Calculating Interior Lighting Power Allowance, allows you to:
d. The interior lighting power allowance for the building is thesum of the lighting power allowances of all building area types. Trade-offs among building area types are permitted provided That the lighting inside the total installed power does not Exceed the indoor lighting power allowance.
In our project interior lighting is very efficient in saving energy, being below ASHRAE 90.1-2007 parameters, can make a trade off between exterior and interior lighting?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5899 thumbs up
March 15, 2012 - 9:08 am
1. If the fixture lights the terrace then no.
2. Yes it is 5% of the total.
3. Where is the lighting? How big are the terraces? Assuming they are relatively small and the lighting is at the door I would think that 20 W/lf of door may make more sense.
4. Exterior lighting is a mandatory provision so you cannot exceed that and comply with LEED. Interior lighting is not a mandatory provision but can be traded off with any other prescriptive area.