Specifications are critical to the success of lighting design work and ultimately make the project. One of the most essential aspects of producing a quality lighting design is to ensure that the lighting products specified are actually acquired and installed on a project. It sounds simple enough but in the reality of everyday practice, this is not always the case.
THE ROLE OF THE SPECIFICATION The purpose of a lighting specification is to chronicle the lighting products (and their locations) required to achieve the lighting design intent. The documentation needs to be clear and precise and typically includes the following three components: an outline specification, a lighting fixture schedule, and product data/manufacturer catalog sheets. Together, this information is considered a lighting specification.
An outline specification is a written document that describes general conditions, product expectations, and execution of the work as related to the lighting products. This is typically done for every trade package on a project according to the Construction Specifications Institute (CSI) 50 divisions that standardize information, which is compiled into construction project manuals. Lighting specifications are located in Division 26–Electrical. The individual(s) in charge of preparing the lighting specification must coordinate with the team leader to ensure that documentation is formatted properly and meets the specific project requirements in order to be included in the master specifications for a project—the complete set of specifications for every component of the project.
The lighting fixture schedule is usually in the form of a chart, matrix, or table. It provides a list of fixture types, which are keyed to the lighting drawings. It typically includes a brief description of the product, a manufacturer product ordering number, and lamp information (including lamp type, wattage, voltage, beam spreads, and color temperature, if applicable).
The final component of the lighting specifications is the product data/manufacturer catalog sheets. These provide a “visual” reference of the product, which has been noted on the fixture schedule.
As mentioned above, the outline specification follows a rather strict guideline. However, there are several types of specification approaches that often are considered when preparing the lighting fixture schedule and product data/manufacturer catalog sheets. The most common are: single-name, multiple-name, and performance specifications.
SPECIFICATION TYPES Single-name specifications (also known as proprietary specifications) typically are used when only one product is suitable for the application and/or no known equivalent exists. This type of specification identifies the one and only product by manufacturer name and specific catalog number.
Multiple-name specifications are used when several available products meet the design, performance, and budgetary requirements of the project or application. In this instance, two or more products are listed by manufacturer name and catalog number. Alternatively, a multiple-name specification can be done by listing a preferred product, along with up to two alternates listed with manufacturer name only.
Lighting specifiers should keep in mind that no two products are truly “equal,” as this would most likely involve copyright and patent infringements. Therefore, it is better to use the term “equivalent” and evaluate the photometric properties to determine if the lighting performance criteria will be fulfilled.
Multiple-name specifications, however, are not ideal for design intensive projects as they do not allow the project team to fully plan, budget, coordinate, and detail the design since which product ultimately will be provided to the project is unknown. In this case, there is another option to consider: performance specifications.