Lighting Standards For Higher Education

IACLEA has established lighting standards for higher education (see below). I am told that these are lighting measurements are intended to be taken at waist height. When specifying video and considering minimum light levels to match camera specs (or to pick a capable camera to meet existing lighting conditions), my belief is one needs to take into account target area reflectivity (e.g. concrete, grass, asphalt) and measure the lighting at ground level. I am concerned with how to reconcile these two expectations.

Lighting is expensive to install, maintain and sustain from an energy consumption perspective. Clients are all tending to want to "Go Green". The IACLEA standards when compared to IESNA seem to be very high but the measurements may be taken differently.

Would you believe that there would be a need to present two light levels to the Owner - one to meet IACLEA and one that reflects actual light from the ground surface considering the reflectivity issue for video?

Thanks, Frank


4fc = ~43 lux. Even if that is a black top parking lot with poor reflectivity, that's a lot of light.

By contrast, when we do lux measurements at random parking lots, 5 lux is fairly common (i.e., .5 fc)... unless you are talking about a car dealership lot, which are lit up like a Christmas trees.

How many organizations are actually delivering 4fc / ~40 lux saturated across parking lots? Those that do, more power to them and great for surveillance systems but it strikes me as the exception rather than the rule.

Frank, is this actually being widely enforced?

John,

I really can’t speak to whether this light level is widely in use across a lot of Universities because I don’t think that our client base represents a huge sample of the many higher education institutions across the nation. My question was really more of a technical one to determine the relationship between measuring light at waist height versus ground level and whether anyone had encountered this before.

The bigger technical issue is where the lux meter is pointed towards. If it is pointed up towards the sky / lights, it is going to generate a far greater reading than if it aimed parallel to the ground. We measure lux levels parallel to the ground, i.e., towards where a camera would typically be. This is a more conservative way but more representative of the light one gets / has to generate images.

Do you know how the lux meter is supposed to be aimed for these reading?

Background for others: Training: Using a Lux Meter

The IESNA guideline for security lighting (IESNA G-1-03) has some very specific procedures for taking light reading measurements in Annex C at the back of the document.

Traditionally, horizontal illumination (meter facing towards the sky) has been used when establishing lighting guidelines, but as John suggests, vertical illumination (meter facing towards the camera or person viewing) provides a more useful reading for practical purposes.

I have found that it generally makes very little difference if the meter is on the ground or at 4' off the ground. An exception would be when the principal source of light in the area is pathway lights that are mounted down low. In this case, you need to get the meter down on the ground. (Not that pathway lighting is that useful for surveillance).

I think that handheld light meters are best used to establish the order of magnitude of lighting (is it 1 lux, 10 lux, or 100 lux) rather than to obtain precise readings. I own several different light meters and sometimes place them side-by-side when taking readings. I often see variations of as much as 20% between meters. I also take a reading, then go back to the same spot later to take the reading again, and the readings almost never match. So again, I think that light readings taken in the field provide a good approximation of conditions, but shouldn't be considered scientific by any means.

The IACLEA standards are very aggressive and I would be surprised if they are actually followed by many institutions. I have taken light readings at hundreds of sites over the years, and I would say that less than 5% of them have lighting at the levels that IACLEA suggests.

We are starting to get more and more pushback from architects these days about security lighting, and I often have to fight like hell to get the one-footcandle (10 lux) minimum light level that I normally suggest. I had one hospital project recently where the architect was going for a LEED Platinum certification and suggested no lighting at all in the parking lots. I was able to overrule this insanity, but didn't get anywhere near the light levels I wanted.

Frank, I think that your approach of presenting both the IACLEA recommended light level and a more practical light level is a good one. The client owns the risk and it is ultimately up to them to make the decision. Our job as consultants is to provide them with the necessary information.

Michael, insightful comment as usual.

Btw, this made me laugh:

"I had one hospital project recently where the architect was going for a LEED Platinum certification and suggested no lighting at all in the parking lots. I was able to overrule this insanity, but didn't get anywhere near the light levels I wanted."

I remember a while back, a certain segment of the CEPTED community seriously argued that no lighting was a better deterrent than lighting, the reason, if I understand correctly, was that even criminals liked to have lightning to help them commit their crimes.

As for that hospital, good grief, security aside, lighting is important simply for people to find their own cars.

The CPTED argument wasn't that lights shouldn't be put up anywhere. It was specific to facilities which aren't manned at night, where no one should be. I belive they did studies at some large rural school district or something similar. The theory was (and according to the study, it was confirmed) that criminals required light, so they would need to use a flashlight if building lights were off. So seeing someone waving a flashlight around a completely dark facility would more easily highlight the activity to bystanders, and criminals would realize this.

It makes sense to me, but I'm not about to turn all my lights off and find out.