Illuminated Signs: Common issues in permitting LED displays


Photos courtesy Daktronics

By Roger Brown
Regulatory issues have often posed a barrier to the sale of large-scale outdoor light-emitting diode (LED) displays. In some cases, they have faced moratoriums or outright bans. In others, sign shops and their clients have at least encountered difficulty acquiring permits.

The best way to address the challenges that have become common in the permitting of large LED-based digital signs—both in terms of helping sign shops get permits and of encouraging governments to adopt appropriate regulations that balance the public’s esthetic concerns with the business community’s need to capture attention with signage—is through education. Many complaints about propositions for outdoor LED displays are a matter of comparing apples to oranges, such as when citizens in a small town complain, “We don’t want to look like Las Vegas!” Officials in different jurisdictions need to understand exactly what businesses and sign shops are actually asking for.

Similarly, when an existing sign is too bright and/or animated for its location, it hurts the entire sign industry, because locals will fight any further attempts to put up electronic message centres (EMCs) in the future. It is very important to improve the reputation of the sign industry by highlighting appropriate esthetics and showing how LED displays can be not negative additions, but rather positive assets, to their communities.

This process of education will be a matter of addressing some of the most common issues that have been raised in opposition, including sign brightness, message hold times and transitions, display areas and safety concerns.

The most common concern expressed about EMCs and other large digital signage is brightness. Some signs are not dimmed properly at night, for example, which not only bothers people nearby, but can also result in higher-than-necessary power bills for the client, while making text less readable and thus less effective at accomplishing the sign’s purpose.

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With this in mind, it is important to sign shops, their clients and the public for appropriate levels of brightness to be maintained throughout day and night. In response to the issue, the sign industry has collectively developed technical standards and suggested them as a regulatory framework for jurisdictions.


Most outdoor LED displays are nowhere near the scale of those in Las Vegas, Nev., as citizens tend to fear.

It is hoped this effort at consistency will help avoid the problem of officials being sent out to make permit-related decisions on the fly (e.g. “I like this sign, but I don’t like that sign). Rather, an objective, repeatable standard could be tested in the field with technical equipment. Such standards, promoted by organizations like the Sign Association of Canada (SAC) and the International Sign Association (ISA), have been a great gift to the industry, as many brightness concerns have gone to the wayside. ISA’s EMC brightness guide, by way of example, was last updated in August 2016 and is based on peer-reviewed research by Ian Lewin, whose company—Lighting Sciences—specialized in lighting testing and was acquired by Underwriters Laboratories (UL) several years ago. SAC has also published a book about EMCs for its members.

There are two parts to illuminance standards that have been put forward in this context. The first is a requirement for any permitted EMCs or digital billboards to have automatic dimming capabilities in direct correlation with ambient lighting conditions during the course of the day and the night. This means no one has to go to the sign and manually change its brightness at different times.

The second part of an illuminance standard, which affects the degree of dimming, recommends the maximum brightness of a sign to be limited to 0.3 footcandles (fc) of illuminance above ambient light levels, when measured at an appropriate viewing distance. This is the response to the aforementioned situation where an enforcement official in the field takes a measurement of a given sign’s brightness.

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