Writing a successful lighting specification is about dotting your i’s and crossing your t’s. As Landscape Forms Vice President of Sales Scott Reinholt, ASLA, summarizes: “The devil is in the details.” In order to increase the odds that products favored by a landscape architect are selected, it’s important to focus on product performance and take the time to make sure nothing has been left out. Fortunately for landscape architects and designers who are familiar with writing a specification but may not be as familiar with lighting data, Landscape Forms’ representatives and lighting specialists are excellent resources to help develop the lighting portion of a specification.

“Engage the Landscape Forms lighting team early,” suggests Reinholt. “They are experts and can assist with layouts and lighting calculations, coordinate special needs, such as banner arms and catenary arrangements, and can help ensure the landscape architect’s design intent is maintained.”

Projects that use public money often require that a specification include a list of equal products, typically three, and that the manufacturers are identified. With this type of spec, it is important to select products of equal value in terms of design, performance, and durability. Oftentimes, the designer will take a good/better/best approach to luminaire specification, which can lead to a less-than-ideal lighting outcome that falls short of the designer’s intent. Reinholt sees a lot of specs that really aren’t equal at all. “It’s frustrating to see a specification lowered to commodity level products.” Never offer more than three options in a spec, advises Reinholt.

Another type of spec that public clients will allow is an or-equal spec that lists only one product and manufacturer as the benchmark, though an or-equal product may be substituted. With publicly funded projects, there is always a concern that identifying one manufacturer may lead to a more expensive product than a competitive bid would, thus the mandate for an equal substitution. Reinholt has worked with municipal clients, however, who are savvy about writing performance criteria into the specifications. Doing so guides the bid toward the product quality and design the owner favors. When writing an or-equal spec, Reinholt advises listing the criteria that will steer the contractor toward submitting a product substitution that equals the price, quality, and performance range of the designer’s product choice. That way, says Reinholt, “the product you favored may not be chosen, but you will still end up with a quality finalist versus a low-quality commodity product.”

There are also performance specs written around a specific manufacturer and product that can’t identify the manufacturer and product. In this case, the landscape architect can get so specific about the product that it becomes difficult to find another competitive product that is exactly the same. “A designer can control the process much better with a performance spec,” says Reinholt.

Here are a few areas to focus on when writing a performance spec.

Color Rendering Index (CRI)

The CRI designates how accurately colors are rendered with a specific fixture. As an example, natural light on a sunny day has a CRI of 100. A manufacturer that produces lights with a CRI of 80 or higher is using high-quality LEDs, so listing CRI in the spec can narrow the field of competitors.

Color Temperature

Limit products to those offering a color temperature below 4,000K. Low-cost, low-quality LEDs tend to have bluer high-color temperatures, which decrease visual comfort and the overall experience of the space. “For these reasons, it’s important to specify color temperatures lower than 4,000K," says Reinholt.

Working Life Performance

Lumen Maintenance measures the decrease in LED effectiveness over time. A quality LED chip will have over 90 percent of lumen output left after 60,000 hours of use. The Illuminating Engineering Society (IES) has determined that LEDs should be replaced at the point when the LED chip produces 70 percent of its original lumens. Find manufacturers that are using LEDs tested to 90-plus percent at 60,000 hours of working life, suggests Reinholt. “These lights will be manufactured to higher quality standards.”

Distribution Types

Be specific about the distribution types your project requires. A Type I luminaire may be best for a narrow roadway or pathway, while a Type IV is better at providing light for a large open pedestrian space such as a plaza. Landscape architects can narrow the scope of competitive products by selecting only the distribution types appropriate for their design.

Environmental Considerations

Specifying fixtures that avoid light trespass and skyglow are better for people, animals, birds, and the environment at large. Select the BUG (Backlight Uplight Glare) rating for appropriate lighting angles without overly lighting a space.

Materials and Construction

Include information on the materials and elements of a fixture such as cast aluminum dimmable drivers, lighting class LEDs, and high-quality paint finishes.

“Getting into the nitty gritty helps the landscape architect focus on the capabilities of what a manufacturer can do and results in the selection of the high-quality products landscape architects favor for their projects,” says Reinholt.

Reinholt's final suggestion when allowing a contractor to submit an alternative product not listed on the spec is to limit the period of time in which the contractor can submit an alternative option. Adding a time frame clause to the submittals section limits the time the contractor has to select the alternative. Alternative options should be submitted for review ahead of the bidding process, inclusive of unit pricing. Only approved products or the originally specified luminaires may be submitted for bid.

“When a landscape architect or designer adds a time frame to the spec, it helps them get the products they want,” explains Reinholt. “Specifying a time limit protects the designer who really wants a specific light by putting the onus on the contractor to do due diligence in a designated period of time.”

Reinholt says the time invested in writing a detailed performance spec is worth it and helps ensure the integrity of the landscape architect’s design goals. “Remember you’ve got support from Landscape Forms' lighting team to work with you on product details and performance data.”