Lighting Power Density

So are these lights interior or exterior? If they are outside then refer to Table 9.4.5. If you are talking about the petrol pumping area where cars pull in to fill their fuel tanks then it sounds like exterior lighting and falls under the Canopies and Overhangs in Table 9.4.5. Not sure but it does not sound as if 9.4.5g applies.

If they are inside then you can use either Section 9.5 or 9.6.

No I do not think it is appropriate to add the drive-through allowance in the pumping island. The drive through is also a non-tradable surface and cannot be traded in any case.

There is a 5% unrestricted allowance contained in 9.4.5 which gets applied to the total. The canopies are a tradable surface meaning you can be over in one area as long as you are under in another and the two at least offset.

Exterior dining does not appear to be covered by 90.1 and therefore should be modeled identically in both model based on the proposed building design.

The composition of the walls does not enter into the lighting calculations. If it is exterior lighting is illuminating the exterior walls then it is facade lighting. Outdoor sales may be appropriate if the lighting is used primarily to light merchandise outside the building.

In our experience the exterior lighting power allowances in 90.1 are more than generous and projects like you describe should be able to meet the requirements. Keep in mind that if the project wants to get LEED certification the exterior lighting provisions are a mandatory provision of 90.1 and as such if not met then the project can't be LEED certified.

So rather than seeking provisions which would allow you to have greater exterior lighting power I'd suggest focusing effort on making changes to your design and the assumptions behind it in order to go beyond mere compliance. It can be done!

Start with the 500 lux requirement - in my experience this level is far more than would be needed for the security of anything. This is the amount I need to sit down and read a newspaper, not to visualize a potential security threat. Table 17-20 in the IESNA Lighting handbook, 9th Edition contains recommended levels for petrol stations. The maximum value is 100 lux for pump areas in light surroundings. Reducing the assumed illuminance value by 5 to 10 times would be a good start.

The level of light for security is an undefined metric ?

You may wish to look at the International Dark-Sky Association's website - they have a document on "Light pollution and saftey", and other documents on energy. While they don't give lux levels they say "Let’s Have Real Security, Not Just Bad Lighting" and then argue for appropriate design.

Are you wanting 500 Lux for the cameras to track money transactions, or because of saftey issues when filling the cars ? Some clients think that high lux levels sell more product ...