Outdoor Night Time Lighting May Reduce Crime

I’ve just learned about a study conducted last year for the New York City Housing Authority (NYCHA).  In a randomized trial 39 NYCHA sites received additional night-time lighting for 6 months, while 38 sites received no additional lighting.  The study showed these reductions in crimes:

Index crimes: 7% reduction in overall index crimes (day and night). This reduction in overall index crimes was driven by a 39% reduction in index crimes that took place outdoors at night.

Felony crimes: 5% reduction in overall felony crimes (day and night). This reduction in overall felony crimes was driven by a 30% reduction in felony crimes that took place outdoors at night.

Assault, homicide and weapons crimes: 2% reduction in overall assault, homicide, and weapons crimes (day and night). This reduction in overall assault, homicide and weapons crimes was driven by a 12% reduction in assault, homicide and weapons crimes that took place outdoors at night.

Misdemeanor crimes: No detectable change in net misdemeanor crimes in treatment communities.

The results of other studies have been mixed, but I’m not clear if they were controlled, randomized studies.

The disappointing thing, from a lighting designer’s perspective, is the data that’s missing.  The report tells us the fixture wattage and lumen output, but doesn’t tell us the area covered or measure the increased light levels.  Instead it treats light fixtures as fixed items and counts them per square block.  This method would be fine if the world had only one type of outdoor fixture, but it doesn’t  So more light is better, but it doesn’t say how much more or what the upper limit should be.

Focal Point Introduces TM-30 Based “Preferred Light”

Today Focal Point Lights of Chicago, IL introduced a series of fixtures that feature what they call Preferred Light.  Preferred Light is based on recent studies at PNNL and Penn State, plus their own study, and uses TM-30’s Rf, Rg, and Hue Bin 16 values to establish a balance of fidelity, saturation, and red rendering that is “visually appealing to humans.”

The overall idea is that people seem to prefer a light source that slightly over saturated most colors, especially red.  “Using a custom LED mix, Focal Point defines Preferred Light using TM-30-15 metrics as having a fidelity (Rf) of 89, a gamut (Rg) of 107, and over-saturating Hue Bin 16, deep red content, by 9% at a [Correlated] Color Temperature of 3500K.”  So, by using the statistical measures of TM-30 and applying them to the related topic of color preference Focal Point has identified an optimized set of LED products to meet their customers’ needs.

I’ll be the first to admit that it may be risky to base all of this on only three studies, but other studies have shown that the TM-30 results can be applied in this way, and are also showing us the relative importance of the various calculated values.  I’m excited to see the industry using the tools, and am looking forward to seeing the Preferred Light for myself.

IoT Lighting? No Thanks.

The current global cyber-attack, combined with last year’s “denial of service attack has me thinking about the lighting industry and IoT.

It was ironic that last year’s attack happened just days before the IES annual conference, at which IoT lighting was touted as the next big thing that everyone had to adopt or be left behind. You may recall that one aspect of that attack was that hackers recruited IoT devices like thermostats and smoke detectors. Many designers may think, “Well, sure, homeowners don’t have good security, but that wouldn’t happen to one of my corporate clients.” The current attack shows the flaw in that thinking. New tools have allowed hackers access to supposedly secure networks, and not all networks that should be secure (such as Britain’s NHS) actually are.

The question, then, is, “Why should my lighting system use IoT?” I’ve asked several friends in lighting design firms large and small and the answers I’ve received are revealing. Almost no one has a client who is asking for this. (I’ve had exactly one client who wanted the lighting system connected to the corporate LAN.) Do they want lighting systems connected to their BMS? If the client is knowledgeable and the building is large, yes, although today’s lighting systems have so many programming options we don’t need the BMS to control the lighting system. Do they want lighting systems to use Wi-Fi so that users can adjust the lights from phones and pads? Not very often. “Why would I want to give that many people authorization to change the lighting?” is the question asked, and rightly so. Do they want light fixtures with IP addresses and built-in Wi-Fi, Li-Fi, daylight sensors, occupancy sensors, temperature sensors, humidity sensors, and software that tracks shoppers or monitors space usage? “How much will that cost?” is the usual first question, followed by a strong “No.”

If we designers don’t see an artistic or operational advantage to these systems, and if our clients don’t see an advantage and aren’t asking for these systems, why all the noise about them? The answer, of course, isn’t better lighting design or increased energy efficiency, it’s money. Companies like Cisco see expanded profits from embedding Cisco sensors in every light fixture in a building, connecting all of those fixtures to Cisco POE switches and perhaps controlling the fixtures and sensors with Cisco software. Fixture manufacturers, always looking for a way to differentiate their products, jump on board. Marketing departments create hype, magazines and web sites need material, and voila! the next “must have” lighting system feature.

Who’s providing network security? The corporate IT department, I guess. Are the lighting systems vulnerable to hacking? The current and recent attacks tell us the answer is, “Yes.” Are manufacturers of IoT devices investing in security? Not really. They see it as the responsibility of someone upstream. Would anyone want a lighting system that is vulnerable to being turned off in an emergency, or reprogrammed by someone just to see if they can do it? No.

Some of the lighting systems I am designing are quite complex involving hundreds of fixtures with hundreds of addresses, multiple control protocols, and multiple points of control including touchscreens and Wi-Fi devices. One thing no one has to worry about, though, is high-jacking or corruption of the system. Each system stands alone. Software updates, if they are ever needed, are downloaded and installed via a USB key. Anyone wanting access to the system has to be within Wi-Fi range and has to hack the network. What would they get? Access to a single lighting system. There’s almost no reward and therefore there’s almost no incentive. Call me a Luddite if you like, but for now I’m going to stick to designing secure, flexible systems that provide my clients with only the features that they want at a price they are willing to pay. I’m sure that the pressure to “innovate” will eventually lead me to using these IoT systems. But for security’s sake I’m going to resist for as long as I can.

Measuring the Value of Lighting Design

The Lighting Research Center at Rensselaer Polytechnic Institute recently published a short video in which LRC director Mark S. Rea discusses the costs and benefits of lighting. Here it is.



If you set aside the plugs for the LRC, his statements, and those in his book Value Metrics For Better Lighting, are similar to what I’ve said throughout Designing With Light, which is that it’s the quality of the light and lighting design that are of primary significance while the amount of light that is delivered is secondary. Therefore, the true value of the lighting design is found in the design’s success in meeting the multiple requirements of the owner and the occupants of the space, not in the cost of hardware and installation.

Unfortunately, there are several factors that have created resistance to placing value on thoughtful, appropriately designed lighting. The first is that most people simply do not see light (pun intended). For far too many people, if the light is bright enough for them to see what they’re doing it is acceptable and little or no judgment is made regarding the other factors of lighting design, such as color rendering, providing visual interest, overall effect on occupants, etc. I find that if I show clients or students the difference between light that is adequate for vision and light that creates an appropriate atmosphere or environment they can see it and appreciate the difference. It is also a surprise to them that lighting design can make such a difference in a space.

The second factor is that project budgets are set in dollars with no little or no allowance made for the quality of the design. I have often worked on projects where the project budget and the lighting equipment budget have been set, although design work has barely begun. I understand that a client only has so much money to spend and that has to be respected. However, 1) No bean counter in the world can predict what the design team will develop. Budgets are more appropriately set in coordination with the design team after the design team understands the full extent of the client’s needs and desires. Then, if the projected cost exceeds the client’s budget, informed decisions can be made to pull back on certain aspects of the building’s design or to allocate more money to construct the building the client wants. 2) Spending more money up front on efficient lamps and fixtures, and on controls, can more than pay for itself in savings on energy and maintenance.

Another factor is that we value what we can measure. Since the early 1900s the lighting design community has invested a great deal in determining how to measure light and on how much light is required for “visual tasks.” Those two aspects became the criteria for evaluating lighting design, and are still presented as primary in many lighting textbooks. In the 1970s John Flynn and others began to study how light can affect the impressions one forms of a space. Later research examined the relationship between a lighting design and those occupying the lighted space including: the affect on worker productivity, absenteeism, and worker retention; student learning outcomes and test scores; retail sales; a light source’s spectrum and clarity of vision; and light’s affect on sleep cycles and other aspects of health. This research has shown over and over again that intelligent, thoughtful, appropriate lighting design can have a significant effect on the occupants and on the owner’s bottom line, whether that bottom line is to make more money, increase student success, or improve health.

Knowledgeable lighting designers can bring so much more to a building than just illumination, yet illumination and lighting design remain synonymous to most of our colleagues and clients. That is part of the reason only about ten percent of construction projects have a lighting designer on the team. Lighting designers and lighting design professional organizations need to do a much better job of educating design team members and our clients about quality lighting design, what it is, and why it matters.

IES Releases RP-31-14 Recommended Practice for the Economic Analysis of Lighting

The Illuminating Engineering Society has released a new Recommended Practice.  RP-31-14 Recommended Practice for the Economic Analysis of Lighting is now available as a PDF download or soft back from the IES Online Store.  From the IES:

Good lighting should be responsive to the needs of the user. Among those needs are the aesthetic and the visual, as admitted in the oft-quoted “lighting is both a science and an art.” But the user also has economic needs. In fact, it is the economic needs that often drive the decision making process when lighting systems are designed and purchased. 

This recommended practice is written from the point of view that “economic analysis” is not the same as “how to beat the budget.” Rather than considering economic analysis as the antithesis of engineering or artistic analysis, is should be thought of as subsuming these other needs. When a competent lighting professional takes care of economic needs, in conjunction with the artistic, engineering, and other needs, it increases the likelihood a project will have success and longevity. Financial considerations ad demonstrated through an accurate lighting financial analysis are important, but other elements such as aesthetics, human visual performance resulting from a lighting system appropriate to a given task, and other considerations involved in lighting for the human and natural environment are of equal importance.