The IDA/IES Model Lighting Ordinance:
No Help for Dark Skies

The IDA/IES Model Lighting Ordinance that is nearing approval by the Board of the International Dark-Sky Association is deeply flawed. It is the conviction of the undersigned that the IDA/IES MLO:

• Will not “preserve and protect the nighttime environment.”
• Will not significantly curtail light pollution in the U.S. or elsewhere.
• Will undermine 50 years of progress in light pollution control achieved by the best state-of-the-art lighting ordinances already in place.

As outlined below, the IDA/IES MLO encourages excessive outdoor lighting levels, allows excessive and often unnecessary uplight, and perpetuates and exacerbates the status quo in overlit urban areas.

It might seem premature to pass judgment on the IDA/IES MLO before its final form is made public. However, given the nature of the development process exhibited to date, the presumption of adoption apparent in statements by many on the IDA Board of Directors, and the training/“educational” sessions being offered by IDA, IES, and IALD, the undersigned individuals and groups feel compelled to share our assessment at this point. We offer these comments with the hope that IDA may yet reconsider its intention to approve the IDA/IES MLO. This statement will be amended or supplemented when final text of the IDA/IES MLO is released.

A flawed process...

The process by which the IDA/IES MLO has been developed leaves us little reason to expect that the critical deficiencies outlined below will be adequately addressed in the final revision.

Lighting manufacturers and designers have an overwhelming majority on the IDA/IES MLO Task Force. There is no representation by scientific experts in light pollution and little representation by informed local activists that are critically aware of the kind of regulations that will and will not work in their communities. It is only natural that the problems and solutions are perceived differently by those in the lighting industry than by those seeking to protect the nighttime environment. For example, industry representatives often assert that “quality lighting” is the solution, whereas dark-sky advocates believe that much more is needed to protect the night, including better analysis of if and when artificial illumination is beneficial at all.

As a result of these fundamentally different perceptions, there has been substantial effort devoted to assuring that the IDA/IES MLO accommodates “standards” established by the lighting industry, while there has been no effort during the development process to assure that the IDA/IES MLO will truly protect dark skies. The little “dark-sky benchmarking” that has been done by IDA appears to be too little and too late to affect the document. A requirement that the IDA/IES MLO must be demonstrated to reduce light pollution was explicitly rejected by the IDA Board of Directors in 2007.

...inevitably leads to a flawed result

Among the problems:

• Because the IDA/IES MLO is explicitly designed to accommodate preferences of the largest U.S. metropolitan areas, it sacrifices meaningful protection of night skies that has been achieved in many smaller jurisdictions – the communities that actually have dark skies to protect.
• Approval of the IDA/IES MLO will make it more difficult to maintain existing effective, stricter lighting codes, as opponents will (and already have begun to) state that these local codes do not comply with the model produced by IDA/IES.
• Similarly, it will become much more difficult – perhaps impossible – to enact new codes that are strong enough to actually curtail light pollution.
• The complexity of the IDA/IES MLO will require both developers and adopting jurisdictions to hire professional lighting designers for nearly every project, large and small. This complexity and additional expense significantly decrease the likelihood of adoption, particularly in smaller or rural jurisdictions where dark skies are often more highly valued.
• Despite the outstanding White Paper on blue-rich light produced by IDA, the IDA/IES MLO makes no effort to address this important problem.

The IDA/IES MLO’s fundamental problems are principally due to the interaction of Lighting Zones with the new BUG luminaire rating system, permitted uplight, and lumen allowances.

Lighting Zones — The preponderance of language in the IDA/IES MLO describing lighting zones indicates that LZ’s are to be assigned based on existing land uses and lighting levels – not on environmental or dark-sky goals. This approach will, of course, tend to perpetuate the status quo in outdoor lighting.

BUG — BUG ratings were developed by lighting-industry members of the IDA/IES MLO Task Force based on characteristics of existing luminaires they thought were good.

In addition to the arbitrary manner in which the ratings were developed, BUG presents serious obstacles to implementation of the IDA/IES MLO because ratings do not exist for many luminaires.

Uplight — In direct conflict with long-standing IDA policy, the IDA/IES MLO allows unnecessary uplight (excepting Lighting Zones 0 and 1 under the Prescriptive Method only). It does not distinguish between cases where small amounts of uplight may be justifiable and the great majority of applications where there’s no reason to allow uplight.

BUG’s specification of uplight allowances in absolute (rather than proportionate) lumens does not limit overall uplight because high-wattage luminaires that exceed uplight allowances can simply be replaced by more luminaires using lower-wattage lamps.

Lumen allowances — The IDA/IES MLO is designed to accommodate generous IES Recommended Practices in Lighting Zone 2, but it has never been demonstrated that following IES RP's will reduce light pollution. Yet even these levels are doubled and tripled in two still brighter lighting zones, with no justification from the perspective of an organization dedicated to “preserve and protect the nighttime environment.”

Existing lighting codes that limit output to 100,000 lumens per acre can and do permit adherence to major IES Recommended Practices such as RP-20 (parking facilities). But a review of actual site plans indicates that even for LZ-2, IDA/IES MLO will permit approximately 120,000 lumens per acre under the Prescriptive Method and around 400,000 lumens per acre using Performance Method Option A. Prescriptive Method allowances for these sites rise to about 250,000 for LZ-3 and roughly 400,000 lumens per acre for LZ-4. Similarly, the 400,000-lumen Performance Method Option A allowance for LZ-2 rises to around 800,000 for LZ-3 and over 1,000,000 lumens per acre in LZ-4! Although the limits to off-site impacts in Option B might decrease these very large Performance Method allowances, there is no requirement to use this Option nor any evidence that doing so would effectively limit light pollution.

Lumen allowances in excess of what is required to meet already generous Recommended Practices are unacceptable. Though little is known about the amount of light used where no lumen caps are in place, the available information indicates that IDA/IES MLO allowances are in most cases considerably above even unregulated practice. It has been argued that, while not perfect, the IDA/IES MLO would still represent progress in the effort to preserve and protect dark skies. But with the extravagant lumen allowances noted above, and the success of existing codes based on simpler and tighter lumen caps, it is our assessment that IDA/IES MLO cannot be defended on those grounds.

This MLO represents much more the perspective and interests of the IES and the lighting and design industries than it does those of the nighttime and dark sky conservation community. In the real world, IDA approval of this document will jeopardize dark-sky protection already in place and hinder the development and enactment of better regulation for a long time to come.

December 16 2010