We see here that we have two ways to calculate our interior lighting power allowance and

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Kevin Stokes
7 years ago
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1 We see here that we have two ways to calculate our interior lighting power allowance and that we can use those methods on either the building as a whole or on separately metered or permitted portions of the building Please note that if we use the Building Area method for one part of the project and the Space by Space Method elsewhere, we may not tradeoff watts between those two areas. 16

2 Here we have a building with retail on the ground floor and office space above that and we want to now how we might go about calculating the LPD allowance. ================================================================ If we look at the build as a whole, we can use either method for that whole or, if the two areas are metered or permitted separately, we can handle those two areas separately but then, we can trade watts between the two sections only if we use the same method in both sections. The two methods mentioned here are the Building Area Method and the Space by Space Method These are covered in the next few slides 17

3 Here we see the step by step instructions for calculating the LPD allowance using the whole building method. It boils down to multiplying the area of the building by the LPD from Table The icon you see here links to an embedded spreadsheet which can be used to help determine the ILPA In the spreadsheet: Data may be entered in the yellow cells Options may be selected by drop down menu in the blue cells The remaining cells will auto fill as you enter data 18

4 Likewise this is the space by space procedure where we add up the individual allowances of each space (or room) calculated by multiplying the area of the space by its LPD from Table Also we have a spreadsheet here for the Space by Space Method that operates similar to the previous one. ================================================================ Note that an enclosed space that serves multiple purposes by area within the space may need to be treated as separate spaces and ================================================================ Note that the area of the space is NOT just the interior area of the space. The limits of a dimension are to the exterior surface of exterior walls and to the centerline of interior walls. 19

5 Here we see a couple of examples including: How to handle the odd case of atriums, and =============================== We see we get 0.6/sq.ft for the first three floors and then it s.2 watts/sq.ft for each floor after that ================================= Then we see an example involving a hotel lobby 20

6 The lighting in some applications are not to be included in the calculation of either the lighting allowance or the installed lighting as long as such lighting: is there, in addition to the general lighting in the space and is controlled separately from the general lighting The next couple of slides lists those applications 21

7 And here we see the first of two slides listing all of the applications where the interior lighting is exempt from the wattage threshold. [Pause] 22

8 As we look at the 2 nd half of the list, let us remember this lighting is exempt only if controlled separately from and is not part of the general lighting for the space in question. 23

9 Using the Space by Space Method does allow for additional lighting power allowance in two types of situations as listed here. Some notes on these: ============================================== The 1 watt/sq.ft of decorative lighting is referring to the function, not the type of luminaire ============================================== The amount of additional LPD for retail display lighting depends on the type of merchandise being highlighted; note that just about any space type can have a retail area in it. 24

10 [Read the slide then] ============================================================== I.e. the space must be sufficiently illuminated without any of this additional ILPA lighting turned on. 25

11 And here we see a question about retail window display lighting. Does it matter if the window display is open to the store or enclosed instead? =================================================== Yes, the lighting in the enclosed window is exempt as long as it is controlled separately from the general lighting. =================================================== Then we have a reminder about all display lighting is to be controlled separately from the general lighting 26

Lighting Requirements

ASHRAE/IESNA Standard 90.1-1999 Lighting Requirements Joseph G. Howley Jr., IESNA GE Lighting Immediate Past Chair of ASHRAE SSPC 90.1 Lighting Subcommittee 1 How to Get the Standard Standard 90.1-2001