Following an OPR to design lighting systems
Lighting designers must consider many factors when specifying lighting systems and lighting controls for nonresidential buildings, including the owner’s project requirements
- Know the owner’s project requirements for lighting.
- Understand how to design lighting systems to meet the OPR.
- Determine how to implement commissioning, training and operations and maintenance manuals.
One of the first things a lighting designer should do on a project is to obtain the owner’s project requirements. The OPR contains elements for design and should contain requirements for illumination and related items.
Other items typically found in an OPR:
- Lighting construction budget.
- Code requirements.
- Desired light source, color temperature, color rendering index, etc.
- Desired luminaire type and style. Note that a luminaire definition in NFPA 70: National Electrical Code is defined as “a complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.” A lighting fixture typically includes the metal or plastic components and the lens and may or may not include the ballast or driver or the actual lamps themselves.
- Illumination levels, minimum foot-candle levels, maximum foot-candle levels, maximum to minimum foot-candle ratios, etc.
- Desired controls systems.
- Special requirements such as emergency lighting, daylighting harvesting, dark skies, etc.
- Sustainability goals.
- Commissioning requirements.
- Training requirements.
- Operations and maintenance requirements.
With smaller projects, the lighting designer may not receive an OPR. In this case, the lighting designer should go over the key lighting elements with the owner. Another approach is to work with the architect to develop a basis of design that lists the key lighting elements and the design approach. This document should be presented to the owner for approval before design.
Lighting construction budget
The budget for luminaires and controls can vary greatly. The lighting designer will need to know the lighting budget to assess if it is realistic for the project’s OPR. Typical installed (including labor and material) square foot costs can range from $5/square foot for a lighting upgrade project to $15/square foot for higher-end commercial projects.
The OPR should state the desired energy-efficiency goals. For example, the OPR may state the project shall meet or exceed state energy codes by a minimum of 15% including lighting. The lighting designer will need to keep this in mind while selecting luminaires and their efficacy (lumens per watt) and total input watts per luminaire.
How does a lighting designer know what codes and standards apply to the designer’s project? A very useful resource can be found at the U.S. Department of Energy’s website, which lists the energy codes for each state. Local codes should also be checked by the lighting designer because local codes may supersede state codes in some states. Also, if a project pursues U.S. Green Building Council LEED certification that will also have an impact on which energy code should be followed.
It is highly recommended to enter luminaires into the COMcheck or other lighting compliance form that is required by the local code authority during the schematic phase or design development phase of the lighting design. Waiting until the end of the 100% construction documents design to check for compliance may result in noncompliance and require changing to different luminaires with lower total input watts per luminaire. This can delay the schedule as typically the architect and owner need to determine if the suggested replacement luminaire is acceptable. There is an online article that shows a lighting designer a step-by-step procedure to complete the COMcheck form.
The OPR should state the owner’s preference for the light source. Most owners want LED lighting due to their long life, lack of hazardous materials (whereas fluorescent lamps contain mercury) and high efficacy.
Color temperature is an important detail; if it’s missing in the OPR, it should be obtained. A typical office color temperature is 3,500 Kelvin. However, some owners may want a higher color temperature such as 4,100 Kelvin, and some want even higher color temperature.
Conversely, some owners — especially in the hospitality industry — want warmer color temperatures such as 2,700 Kelvin. It is important for lighting designers to find out the desired color temperature because it can be costly to replace entire luminaires or components of a luminaire if the incorrect color temperature is specified.
Some retail owners may require high CRI. The minimum CRI level should be stated in the OPR.
The R9 color rendering index is another value that owners may state. LEDs may have difficulty rendering red colors well. High R9 values are desirable in restaurant, food and retail applications.
Desired luminaire type, style
Typically, lighting designers work with architects and owners to determine the type and style of luminaires selected for a project. For example, an owner may require linear LED luminaires that are end-to-end for a long corridor with a frosted lens. The lighting designer should ask for additional details if it is missing from the OPR. For example, if the OPR did not state frosted lens and the lighting designer specified a clear lens, then this could result in a costly change order if ordered and installed.
A recent project involved an architect that requested clear lenses for recessed can LED luminaires without consulting the owner. After installation was completed, the owner said the glare from the luminaires was unacceptable and frosted lenses replaced the clear lenses.
It is also critical that the lighting designer select the correct luminaire for the ceiling type. An example of improper coordination is when a lighting designer specified a surface-mounted luminaire for multiple operating rooms and the architect specified a lay-in ceiling. The luminaire was custom-built and more than 100 were ordered. Unfortunately, the luminaire could not be modified with to fit within a lay-in ceiling. This delayed the opening of the operating rooms and new luminaires had to be purchased.
The lighting designer needs to know if the owner would like to meet Illuminating Engineering Society lighting levels or if there is another requirement. The IES has recommended minimum lighting levels depending upon the type of space and the users or occupants in that space. The age of users also comes into play as older occupants may require higher light levels compared to younger occupants.
A typical OPR may state: “The lighting levels (a combination of the natural lighting and electric lighting) in the open-office area shall provide a maintained illumination average of 30 horizontal foot-candles (minimum) without the use of task lighting measured at the work plane height. Daylight harvesting shall be used to achieve the required foot-candle levels.” It is important to know where the measurement of light levels occur. Typically, this is at the work plane level, which is an industry standard of 30 inches above finished floor.
The OPR may leave out requirement for lighting levels for certain rooms/areas that are deemed noncritical or for transition areas like corridors. The IES recommended corridor light levels are typically much lower than what is stated for recommended office light levels. Some owners have been dissatisfied with low corridor light levels even though these levels meet the recommended IES level. The owners wanted light levels in the corridors similar to office light levels. The lighting designer needs to ensure the OPR has recommended light levels for all areas/rooms to avoid these types of issues.
The owner may have maximum foot-candle levels as well in the OPR. Some owners do not want spaces/rooms to be over lit.
Maximum to minimum light level ratios may be included in the OPR. This is how uniform the light levels are in an area. This typically is used for parking lots to ensure uniform lighting for safety. A typical recommendation is 15:1 for parking lot lighting.
The type of lighting controls should be stated in the OPR. The owner may want a lighting controller tied into the building automation system to control all lighting with time-of-day shut-off.
The OPR should also state if wireless controls are acceptable. Some owners do not want wireless controls; they prefer hard-wired options.
Owners may want a different lighting control for a room than what is acceptable by the energy code. For example, an owner may want only light switches in a conference room and no other type of control. However, the energy code may require an automatic shut-off device such as an occupancy sensor. The lighting designer shall review the OPR and advise the owner of conflicts between the OPR and codes to avoid issues later in the project. The engineer of record (usually a licensed professional engineer) for a project shall comply with the applicable codes, including the energy code. The owner cannot mandate that codes be ignored.
For instance, an owner of a jewelry store wanted a new high-end jewelry store to be built. The OPR stated to use all halogen light sources in the sales area. At the schematic design level, the lighting designer informed the owner that the current energy codes would not allow all halogen light sources in the sales area. Ceramic metal halide light sources were used that were acceptable to the owner and also met the energy code. After the new store was completed, the owner decided he liked the new ceramic metal halide luminaires more than the halogen light sources.
Owners may require occupancy sensors in private offices to control both luminaires and heating, ventilation and air conditioning devices. For example, if the occupancy sensor does not detect anyone in an office, the owner may require the lighting be turned off in the room and have the HVAC variable air volume box move the damper to the minimum code–required position to save energy.
Dimming should also be covered in the OPR. Does the owner want 1% dimming? If so, dimming controls will need to be specified that are compatible with the dimming luminaires.
Scene control in certain rooms such as large classrooms and auditoriums should be specified in an OPR. For example, an owner may want pre-programmed scenes for a classroom with audiovisual projectors.
Site lighting control in the OPR should state if photocells should be used in each exterior luminaire or if one photocell is to be used for control of all luminaires. Time–of–day control also can be used to control outdoor lighting instead of photocells.
Owners should state in the OPR how emergency lighting is to be powered. Emergency egress lighting is typically powered through battery packs, an inverter or a generator. There are some owners that want all lighting in the facility on generator power. The lighting designer needs to follow code requirements for egress lighting while also meeting the OPR.
Owners may want to implement daylighting harvesting to save energy. It is important for lighting designers to determine the extent of daylighting harvesting that owners desire. Simply stating “incorporate daylighting harvesting” in an OPR does not provide enough information for the lighting designer.
The OPR should state which rooms daylighting harvesting is desired. The lighting designer should keep in mind that energy codes may mandate which spaces are required to have daylighting harvesting and if multiple daylighting zones are desired. The OPR should also include dimming levels (1% or 10%) and also how many rows of luminaires should be controlled per room/area.
Owners may state in an OPR they require exterior lighting fixtures to have certain backlight, uplight and glare ratings. BUG is an acronym coined by the IES and the International Dark-Sky Association. The BUG rating of a luminaire determines how much light trespass the luminaire produces. The OPR may state to meet the LEED BUG requirements.
Circadian lighting is a growing movement for owners to incorporate into their buildings. The color and intensity of light can be used to regulate the timing of humans’ biological clocks, also known as circadian rhythms. There are claims of improved employee productivity, reduction in obesity, shorter hospital stays and other benefits of using circadian luminaires.
Owners may want to meter or track the lighting energy usage and run–time of luminaries. There are several strategies to incorporate this such as installing a sub-meter on the lighting panelboards and tracking energy usage through the lighting control software or BAS.
Tracking the amount of time luminaires are on can help an owner with determine when it is time to replace luminaries as they approach their end of life.
For example, an OPR states the minimum level of LEED certification and sustainability goals. The statement could be: “Project shall achieve a minimum of LEED v4 Silver Certification.”
The lighting designer will typically need to complete the LEED (or other certification) online template documentation for each lighting credit. Also, the lighting designer will most likely need to work with the person doing the building energy model to incorporate controls and specialty items such as daylighting harvesting into the model.
Commissioning of lighting systems is important to ensure the systems are working as the lighting designer intended.
An OPR should state if the owner’s commissioning requirements for lighting and other systems that use energy and affect operation of a building. Energy codes and LEED certification have made commissioning of lighting controls a requirement. ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings requires functional testing of lighting controls and systems.
LEED and other sustainability certifications require commissioning in order to obtain certification.
Ongoing commissioning should be recommended to an owner. This process is to ensure that the lighting systems continue to operate and save energy as originally designed.
The lighting designer should work with the commissioning authority/agent early in the project, preferably the pre-design stage to determine the commissioning requirements for the lighting systems. For example, the commissioning authority or agent may do a review of the design documents and review lighting related shop drawings. The commissioning authority/agent reviews the OPR and the design team’s BOD to ensure the OPR are met.
Training for an owner’s facility personnel is important to ensure the lighting system is operating after the construction is completed and the building is turned over to the owner. The OPR may state training is to be videotaped and provided by a factory–trained or authorized representative from the lighting controls company. The lighting designer needs to incorporate the owner’s training requirements into the specifications
In addition to training, the OPR should state what documentation is required for the contractor to turn over to the owner’s facility staff form operations and maintenance of the lighting system. This typically includes record drawings of as-built conditions and the specifications. Shop drawings of the luminaires and the control devices are usually required as well.
The lighting designer shall incorporate into the specifications the requirements for the O&M manual as directed by the OPR.
An OPR is critical to the success of a lighting project. There are many critical lighting items that need to be listed in an OPR. The lighting designer shall meet these requirements in the design for an energy-efficient lighting system.