I recently had the opportunity to interview Levin Nock, PhD, Senior Technical Manager, DesignLights Consortium (DLC), for an article about the DLC’s new LUNA requirements I’m writing for the June issue of ELECTRICAL CONTRACTOR. Transcript follows.

DiLouie: How prominent are outdoor luminaires in utility rebate programs, and what role does the DLC and the Qualified Products List play in these programs?

Nock: Outdoor luminaires comprise nearly half of all the products on the DLC Solid State Lighting Qualified Products List. According to BriteSwitch energy information, 90% of energy efficiency programs across most of the US and Canada offer rebates for DLC qualified outdoor lighting.

DiLouie: Generally, what is the purpose of LUNA Technical Requirements V1.0?

Nock: The DLC LUNA requirements are intended to mitigate negative impacts of lighting at night by establishing system performance specifications and best practices with the following goals:

1. Minimize lighting energy use. In addition to meeting the efficacy thresholds of the DLC’s SSL V5.1 Technical Requirements, LUNA qualified products must meet additional dimming, control, and shielding requirements to ensure efficient use of lighting energy. These thresholds will help efficiency programs meet or exceed their energy savings goals and end users reduce operational costs.

2. Minimize light pollution. The LUNA program introduces requirements for light distribution, correlated color temperature (CCT), and dimming controls that ensure less light is scattered into the atmosphere, resulting in reduction of light trespass and sky glow, and darker skies for stargazers, astronomers, and wildlife.

3. Provide appropriate visibility for people. The LUNA program incorporates all SSL V5.1 spectral quality requirements, BUG reporting requirements, and additional spectral power distribution and intensity distribution reporting requirements, enabling lighting installations to meet recommended practices and voluntary guidelines for dark-sky best practices.

DiLouie: Is it complementary to current DLC SSL outdoor lighting requirements, or will it be integrated?

Nock: LUNA Technical Requirements V1.0 complement existing DLC requirements for outdoor lighting, with additional requirements that are specific to enabling the responsible application of light at night. LUNA qualified products not only meet the existing DLC SSL V5.1 requirements for lighting quality, but also have attributes that help limit light pollution, sky glow, and light trespass.

DiLouie: What are the benefits of LUNA for owners, contractors, distributors, designers, manufacturers?

Nock: LUNA provides a clear way to address light pollution and light trespass while saving electricity and qualifying for energy efficiency rebates and incentives. The LUNA program qualifies warm white LED luminaires that will help meet dark sky policies and ordinances. These products can be used to meet the prescriptive application guidance in the Joint IDA-IES Model Lighting Ordinance (MLO). LUNA products can also be used to meet the light pollution and trespass requirements for LEED certification. And LUNA products of 2700K to 3000K CCT can be used to meet the light pollution and trespass requirements for 2021 WELL certification.

DiLouie: What does the DLC anticipate for participation by the end of 2022?

Nock: Considering that a third of all artificial outdoor light in the US is lost by unshielded luminaires – costing facility owners over $3 billion every year – and that light pollution consciousness as well as regulations are proliferating, we anticipate extensive participation by the end of 2022. Readers may find the actual count of products that meet LUNA requirements on the DLC QPL as they become qualified in mid-2022.

DiLouie: In recent years, the DLC broadened its interest in energy efficiency by addressing lighting quality issues with indoor lighting. What was the rationale for doing something similar for outdoor lighting?

Nock: The US National Park Service estimates that at the current rate of increasing light pollution, no dark skies will remain in the continental US by 2025. The DLC has played an important role in enabling the rapid conversion of outdoor lighting to energy-saving LED lighting. Due to a variety of factors including lack of proper application knowledge in the market, the unintended consequence of rapidly increasing light pollution has been identified as an issue. The DLC Technical Requirements have been updated to address lighting quality issues found in both indoor and now outdoor lighting, because we recognize the need to prevent more light pollution and the opportunity to resolve the existing issues. Specifically, the LUNA program enables selection of products that will limit light pollution and trespass.

DiLouie: What impact do you see LUNA having on rebate programs, the market, and the state of outdoor lighting? How do you see LUNA fitting into local ordinances and the IES Model Lighting Ordinance?

Nock: In terms of energy efficiency rebate programs, we expect LUNA qualified products to continue to receive rebates because they meet DLC SSL V5.1 requirements for energy efficiency. In terms of the market and the state of outdoor lighting, we hope that light pollution will decrease as LUNA qualified outdoor lighting products are installed following the IDA-IES Five Principles for Responsible Outdoor Lighting, which essentially call for appropriate consideration of lighting needs for outdoor projects.

LUNA qualified products also enable specifiers to meet local ordinances related to light pollution and trespass using warm white light and meet the prescriptive application guidance in the IES Model Lighting Ordinance.

DiLouie: What impact do you see LUNA having on product development? What percentage of the market currently complies, and how and where will manufacturers need to stretch to comply?

Nock: In terms of product development and the shifting market, we expect to see:

1) more decorative roadway/area luminaires with less uplight, based on the LUNA uplight requirement of U2 or lower;
2) more luminaires with CCT of 2200 K to 2700 K at 105 lumens per watt or higher, based on LUNA spectral and efficacy requirements;
3) more public sharing of luminaire spectral data;
4) more listings of shielded products, due to LUNA shielding efficacy allowances;
5) more efforts to standardize outdoor chromaticity specifications for white and amber spectra; and
6) a broader selection of DLC-qualified bollards, due to the LUNA efficacy allowance.

In terms of compliance, most DLC qualified roadway and area luminaires already have an uplight rating of U0 or U1, and many have a family member available at 3000K CCT. The biggest stretch will be for optical limitations in decorative products and for bollards, even with the efficacy allowance for bollards. The biggest opportunity is likely to be newly qualified products at the lowest white light CCTs.

DiLouie: Controllability is required. What was the rationale for including it, and what are the benefits of providing it?

Nock: Controllability is the key to using light where it’s needed and when it’s needed. Controllability is also a key factor for advanced energy savings.

Whenever an outdoor luminaire is dimmed, by whatever means, sky glow is reduced during the dimmed times. This is true even for U0 luminaires because of reflections from the ground and other surfaces. Dimming can also mitigate light trespass and overlighting.

Also, considering that dark sky ordinances are proliferating rapidly throughout the world, installing a controllable product with a standardized control receptacle today reduces the risk of obsolescence tomorrow. While standardized control receptacles are not required in this version, the QPL will make it easier to find these products.

In terms of requirements for controllability, all LUNA qualified products are continuously dimmable to 20% or less of maximum light output. In addition, details about controllability capabilities and communication protocols are publicly available on the DLC QPL, to support easier selection of lighting products and NLC products that are likely to be compatible with one another.

DiLouie: What control scenarios do you see being enacted using the controllability capability required in LUNA?

Nock: To ensure that light is no brighter than necessary, high-end trim enables specifiers to meet design requirements without overlighting. To ensure that light is only used when it is useful, outdoor lighting can be dimmed down as far as appropriate, as frequently as appropriate. For example, when fewer cars and people are present later at night, lower light levels can be scheduled for street and roadway lighting, compared to evening and morning rush hours when more illumination is needed per ANSI/IES RP-8-21. Similarly, occupancy sensors for area lighting can dim the lights whenever an area is unoccupied.

Smart city projects sometimes invest in networked lighting controls (NLC) with various types of sensors plus centralized dashboards for remote diagnostics, scheduling and energy reporting. However, many LED-retrofit projects do not yet include NLC. New LED luminaires are likely to remain in the field for 15 to 20 years, so future upgrades are an important aspect of controllability and sustainability, to avoid premature replacement. A LUNA-qualified luminaire chosen with a standardized control receptacle and a digital D4i driver can be installed cost-effectively today with either a simple standalone photocontroller, or a standalone photocontroller with part-night-dimming and field-adjustable high-end trim. In the future, as value propositions mature, for instance with 5G buildout, each control receptacle can accept a new piece of digital hardware, to support NLC plus additional types of sensors.

DiLouie: What education and training do contractors, distributors, etc. need to properly implement LUNA-compliant solutions?

Nock: Appropriate project design begins with consideration of the IDA-IES Five Principles for Responsible Outdoor Lighting shown below:

Beyond that, design and application guidance is available from the Illuminating Engineering Society (IES). An extensive list of references is available in the LUNA Technical Requirements.

The DLC recommends that, when possible, a qualified lighting professional assist in designing and implementing a complete project that meets all of an owner’s project requirements, including minimizing light pollution.

DiLouie: If you could tell the entire electrical industry just one thing about LUNA, what would it be?

Nock: With all the infrastructure and roadway lighting projects that will happen in the next few years, now is the time to ensure that lighting solutions minimize light pollution and support decarbonization goals. If practitioners and owners do not minimize light pollution and guard against premature replacement as primary design goals, then the opportunity will be lost for decades. With LUNA qualified products, decision makers can be confident of saving energy AND following best environmental practices for nighttime lighting.

DiLouie: Is there anything else you’d like to add about this topic?

Nock: Lighting is no different than other human inventions and activities in that it does not occur within a vacuum. What, where, and how we illuminate our outdoor spaces has impacts – sometimes profound – on neighboring human communities, wildlife, the environment, and the ability to enjoy and study the night sky. LUNA supports a more holistic view of nighttime lighting that provides appropriate illumination for people, while mitigating light pollution and reining in billions of dollars in energy waste that contributes to the climate crisis.