Performance specifications identify as completely as possible both the quantifiable and qualitative aspects of a lighting product’s performance. This is usually done by a detailed written description of the intended product and may be accompanied by product data/manufacturer catalog sheets of a product that meets the criteria. As a result, any product submitted for consideration must meet or exceed the performance characteristics set forth in the specification, instead of limiting the product selection to only two to three manufacturers. Since any product that meets the criteria can be submitted, it often generates the most competitive pricing.
SPECIFICATION PREPARATION The preparation of lighting specifications is a continuous process that requires detailed coordination with each major project phase milestone deadline. Ultimately, the specifications must include all documentation necessary to assure proper bidding of the project. As such, it is an on-going process to make sure specifications are clear, accurate, and in line with the project requirements and/or any design changes. Specifiers should keep in mind; anything that is not clearly outlined by the lighting specifier ultimately may be decided by “others” including the contractors, distributors, or other team members. In the design phases (such as Schematic Design and Design Development), products are evaluated, lighting calculations are prepared, quotes are obtained, and design work and details are coordinated. In later phases of the project (such as Construction Documentation andConstructionAdministration),valueengineering,designchanges, final detailing, dimming control systems, and budget become a focus of the work related to the lighting specifications.
TEAM COMMUNICATION One of the unique things about lighting is that it generally touches every aspect of a building from interior to exterior. Every space requires it. As such, lighting requires extensive coordination from master plan to a carefully considered trim detail. In addition, large projects often require collaboration with an extended team beyond the architects including interior designers, acousticians, curtain wall consultants, electrical engineers, landscape architects, Leadership in Energy and Environmental Design (LEED) consultants, signage/graphic designers, and others. Communication between all team members, as well as accurate and timely information is essential so that design work and/or changes can be evaluated by the lighting specifier.
Even “small” changes in the project can create a huge amount of work to prepare and maintain accurate lighting specifications. For example, changes in wall material, color, and finishes have an impact on the light levels and lighting effects, which may require alternate lighting products. This, in turn, may require a change in lighting layout, which could affect power density/loads, dimming control systems, and sustainability issues.
Updates and/or revisions to the lighting specification should be highlighted so that they are easy to identify and reissued in accordance with project milestones and other documentation for the project. Often a change to the lighting specification requires additional work including lighting calculations to verify the revised product has a comparable performance. In addition, changes to spacing and location of fixtures may be affected; drawings and details need to be updated accordingly to reflect the change, as well as the coordination with various team members.
REVIEW PROCESS Once the lighting specifications are complete, there are a series of steps that take place before final installation and project completion. This includes the bidding process, review of shop drawing submittals, samples, and/or mock-ups.
Shop drawing submittals need to be evaluated based on the final lighting specification documentation. Some of the evaluation criteria include: photometric and visual performance; overall product dimensions, especially recessing depth, if applicable; wattage, voltage, and light source; mounting devices; trim details and finishes; and accessories.
Mock-ups and tabletop demonstrations can be helpful to confirm and verify product characteristics and lighting performance during specification as well as in the final stages of a project. In addition, many reputable manufacturers often can provide a list of reference projects to view product installations.
TO SUBSTITUTE OR NOT TO SUBSTITUTE? Most lighting specifiers agree that the substitution of fixtures is never ideal. A great deal of time, planning, and coordination goes into selecting the appropriate lighting product to fulfill the lighting design intent. Typically, the overall fixture performance, design appearance, and dimensions have been carefully considered and coordinated.
A variety of problems can arise when products are substituted. Although a product may appear similar, the photometric data may vary significantly, resulting in a difference in light levels, use of energy, or overall lighting effect. There also may be an impact on the design such as recessing depth coordination, variation in mounting devices, or lack of accessories and locking mechanisms.