How lighting design affects the overall building design and construction process
It’s no secret that lighting designers must wear many hats, but according to the Illuminating Engineering Society of North America (IESNA), the actual number of those hats might surprise you. A review of the lighting design process from the association’s Design Guide 7-1994 reveals a lighting designer must not only be adept at both interior and exterior lighting but also function simultaneously as an engineer, artist, code expert, project coordinator, collaborator, administrator, advocate, and evaluator. In fact, lighting design has grown so much in complexity over the years that the lighting industry and the U.S. General Services Administration (GSA) have recognized the necessity of an independent validating organization, such as the National Council on Qualifications for the Lighting Professions (NCQLP), to test and certify practitioners (Seeing the Light). As electrical contractors, it’s important to understand how a lighting designer’s work contributes to the overall design and build process. Let’s take a closer look at how this specialty affects the big picture of a project.
The lighting design process
A review of the lighting design process provides insight into what a client receives when purchasing lighting design services. Perhaps the most comprehensive overview of all that good lighting design encompasses is illustrated in The Lighting Design Process flowchart, (click here to see Flowchart) featured in IESNA Design Guide 7-1994. This chart serves as a helpful work effort matrix, which allocates various lighting design tasks with relevant design and construction phases for a typical building project. Essential lighting design tasks are assigned to each of the following phases of the design/construction process: programming, schematic design, design development, contract documents, bidding and negotiation, construction, and post-occupancy evaluation. Let’s take a look at each of these more closely.
The initial stage in a building project requires a fair degree of innovation, inspiration, and initiation on the part of the lighting designer. Per IESNA DG-7-1994, at the outset of every project, the lighting designer must account for a myriad of considerations, such as user needs and preferences; psychological needs; space functions; visual tasks; quantity/quality of lighting; glare and visual comfort issues; architectural features; coordination with daylighting; color temperature and color rendering issues; flexibility of function; controls requirements; security issues; life-safety considerations; budget concerns; operating costs; maintenance issues; energy codes; and building/electrical codes.
All of these items must be continually monitored throughout the life of a project to assure that the established design criteria is not inadvertently compromised due to substitutions, floor plan reconfigurations, or the like. Oftentimes, changes are initiated by other members of the design team or the client without consideration to the collateral damage on the end-user. Following is just one small example of the value a lighting designer can add to a typical construction project. On one recent project, a contractor wanted to substitute a shielded basket indirect luminaire with a direct downlight luminaire due to plenum restrictions on the project. Although this change seemed innocent enough, the lighting designer promptly pointed out that the light location in question was located directly over a baby diaper changing station — a situation that would not be ideal, due to the fact that babies would be lying on their backs staring up at the bare lamp. Everyone agreed with this observation, and another solution was found.
During the programming phase, the lighting designer confers with the owner, end-user, and architectural design team to establish design criteria and address expectations. If applicable, the designer conducts an initial site survey to establish a design baseline. This early phase of the project requires the lighting designer to assess the project scope, which necessitates asking many questions, some of which might include the following:
- Is the project new construction or a renovation project?
- Does the project have sustainability goals, such as Leadership in Energy and Environmental Design (LEED) certification or compliance with government sustainability regulations, such as Unified Facilities Criteria (UFC) 3-400-01?
- Is site demolition required?
- Are there any building operations and maintenance issues?
- Is daylighting a factor and, if so, what degree of complexity is required for integration of daylighting with artificial lighting controls?
- Are there any hazardous locations on the project?
- What is the schedule for the project — fast track or normal track?
- What are the budgetary concerns?
- Are there any custom fixtures on the project that will require UL testing and labeling (new requirement for NEC 2008 – Sec. 410.6)?
- Will there be exotic luminaires required on the project whose delivery schedule might impact the project’s construction critical path?
- Will the project use a 3-D building information modeling (BIM) platform?
This wide range of issues must be addressed in every building project by a certified lighting professional who is trained to handle such a complex web of responsibilities.
Schematic design phase
During this phase of the project, the lighting designer clarifies specific design criteria established during the programming phase and uses such criteria to design the initial lighting scheme. At this time, the designer identifies preliminary luminaire and lamping selections as well as lighting control schemes and technologies. The lighting designer establishes the baseline lighting layout and typically confirms the preliminary design with computer-generated mock-ups using industry-accepted lighting calculation programs and/or with calculations done manually via the zonal cavity method. The designer also conducts a preliminary energy compliance analysis and preliminary economic analysis. As stated previously, energy consumption and illumination target level considerations are so intertwined in contemporary lighting design that illumination levels have to be checked and monitored in conjunction with energy usage every step of the way.
The schematic design phase builds upon the programming phase in terms of finalizing the conceptual design. If required, full-scale mock-ups to replicate anticipated lighting effects are built at this juncture. At the very least, computerized mock-ups can be created using readily available lighting calculation programs to verify initial design assumptions. All preliminary design considerations are documented in drawings, specifications, storyboards, 3-D computer modeling, etc., and presented to the client for review, comment, and revision.
Design development phase
Refinement is the best description of the work effort during this stage of the project. The client and architect reviewed and approved schematic lighting design is developed further and refined in this process. Details are developed as necessary with the architect for special conditions and/or customized luminaires. The designer begins the process of coordination with other building systems, such as HVAC ductwork and outlet locations, architectural features and constraints, furniture locations, automated shading systems, and the like. In addition, this is the time when the lighting designer initiates a preliminary life safety design to account for code compliance as well as special client requirements.
At this point, if not sooner, the lighting designer solicits involvement of lighting industry manufacturers and vendors to assure a timely, coordinated, and satisfactory project completion. Product availability is investigated, and critical path equipment, such as specialized or customized luminaires, are noted and monitored. As the design is refined, illumination levels and power density calculations are monitored for code compliance. At this stage, the economic analysis is refined, and a budgetary check is in order. The lighting designer now synthesizes all aspects of the lighting design into an official format (drawings and specifications) for the client to review.
Contract documents phase
During this phase, the lighting designer must finalize all aspects of the design. The task of extensive coordination with architecture and HVAC systems is tackled at this time to avoid potential problems in the field. This means a thorough review of plenum spaces to assure that installation of specified recessed luminaires is possible as well as a review of furniture systems and/or stationary millwork locations with the overhead lighting system to optimize luminaire placements. It is not unusual for space programming to change even at this late stage of the game.
The lighting designer must be flexible enough to accommodate last-minute client requests and be diligent to assess the impact of such changes on the lighting design and end-users. At this time, the lighting designer must complete and compile final engineering calculations and prepare them for submission to the proper authorities. Illumination level calculations (interior and exterior) are typically sent to clients for review. Forms for energy compliance are filled out and sent to jurisdictional authorities for review and approval. If the project is a LEED project, appropriate forms and calculations must be compiled and submitted to USGBC for review.
In addition, the lighting controls scheme needs to be finalized at this stage. This means that any interior occupancy and daylighting sensor schemes need to be documented on the drawings, and exterior time clock and photocell lighting controls need to be indicated as well. If more elaborate controls, such as lighting control panels or dimming panels, are required on a project, now is the time to finalize requirements on the drawings and specifications in coordination with recommended manufacturers. The luminaire schedule should be finalized at this stage of the process to ensure that desired lighting fixtures (types and manufacturers), lamping, mounting heights and installation conditions are specified. In short, the project lighting design must be accurately documented in detail on the contract documents (drawings and specifications) for final client review and contractor bidding purposes.
During these final phases, the lighting designer’s work shifts focus from engineering design to construction oversight matters. The primary focus of each segment of the construction phase is clarification (bid phase), administration (construction phase), and evaluation (post-occupancy phase). In other words, the lighting designer serves as a mother hen or police dog watching over the lighting design to ensure it is incorporated into the built environment as originally conceived and documented on the construction documents. During the bid phase and construction phase, the lighting designer answers contractors’ inquiries regarding the lighting design’s intent, documented design criteria, and detailed specifics. Responsibilities during construction include review of submittals, conducting construction field visits, answering requests for information (RFIs), solving field issues, producing a project punch list, and overseeing final adjustments and commissioning of systems. Two typical challenges lighting designers face during this phase are ensuring luminaires are delivered on time and remaining vigilant regarding substitutions of specified equipment.
I remember one particular project where the vigilance of the lighting design team during construction preserved the integrity of the project’s lighting design. The project involved volatile cellulose nitrate storage vaults requiring highly specialized Class 1, Div. II explosion-proof luminaires with a temperature class (T Code) of T6 [NEC 500.8(C)]. After many months of searching, we finally found a manufacturer who made a lighting fixture conforming to such stringent criteria. We specified the manufacturer on the drawings as our basis of design along with the specific required T Code. However, because this was a federal project, we couldn’t single source the luminaire. Our specifications and drawings were specific regarding the strict explosionproof criteria. No questions were submitted to the design team during the bid period, which worried us. We anxiously awaited the submittal for our review. When the lighting submittal finally arrived several months later, we noticed that the electrical contractor had substituted our specified luminaire with a different luminaire having a lesser T Code rating. We rejected the submittal due to nonconformance. The contractor was livid. To expedite construction, he had already purchased the inferior luminaire prior to our review, which was in violation of the contract documents. The project required hundreds of these specialized explosionproof luminaires, so the contractor didn’t want to return them. The design team held firm and insisted on conformance to the contract documents, especially in view of the volatile environment in which the luminaires would be used. Although substitutions were allowed, they had to be equal to what was specified on the contract documents. The contractor eventually relented and installed luminaires in compliance with the documented design. In the end, the integrity of the lighting design was maintained.
The IESNA proposes that the post occupancy phase is a typical part of the lighting design process. My experience has shown that post-occupancy evaluations typically consist of either complaints from the building owner if the lighting design is unsatisfactory or total silence if the lighting system is acceptable. Therefore, it’s difficult for most lighting designers to accurately evaluate the effectiveness of their work. In the NFL, an offensive lineman is considered to have a good game if his name isn’t mentioned at all. In the same way, a lighting designer assumes the lighting system as designed and installed is successful if there is no further comment from the owner upon building start-up and occupancy.
This tendency is beginning to change as the building industry begins to embrace the ideal in sustainable construction of continuous commissioning. In buildings where real-time monitoring of the lighting system is possible and, in fact, required for continuous commissioning purposes (such as for LEED recommissioning), the owner and possibly the designer finally have a legitimate opportunity to accurately study installed lighting systems for the express purpose of improving future designs. Such opportunities, however, are currently rare due to the increased cost of building management systems that enable continuous commissioning. For now, the best indicator of performance for the lighting designer is client feedback.
Reichardt is an electrical designer with Wiley |Wilson, Alexandria, Va. He can be reached at firstname.lastname@example.org.