Commissioning lighting systems
The complexity of lighting design has made commissioning of lighting controls an essential part of projects. Commissioning for the most part is voluntary; however, if an owner is contemplating U.S. Green Building Council LEED certification or if ASHRAE 90.1-2010 compliance is required, commissioning is mandatory.
- Know the codes and standards that define lighting commissioning requirements.
- Understand how lighting controls play a role.
- Determine the commissioning authority’s role.
Many building owners are just now realizing the importance of commissioning lighting systems. Addressing lighting deficiencies via commissioning has been documented to generate a 1.1- to 4.2-year payback (The Lawrence Berkeley National Laboratory, 2009). Studies show that more than 30% of new buildings have lighting deficiencies that could be rectified through proper commissioning (Lighting Controls Association, 2012).
Recently, a large company with more than 2,500 retail stores that included exterior lighting did not have a commissioning process or requirement. A field survey of the stores indicated that most had exterior lighting fixtures with lamps that were lit 24 hours a day, 365 days a year.
Many of the stores had exterior lighting controls that consisted of an astronomical time clock. However, many of these clocks were never programmed correctly, which meant the exterior lighting did not turn on at dusk. The controls were set to override, leaving the exterior lighting on all the time.
According to conservative estimates, 50% of these stores had lighting that did not turn off. Calculations estimated that the company could save more than $1.5 million annually if the exterior lighting for these 50 stores would turn on at dusk and off at dawn.
Commissioning lighting systems helps reduce energy consumption and operating costs. Other benefits include client/user satisfaction and acceptance of lighting control systems. Also, commissioning can result in increased marketability and value of a building.
Lighting controls have grown in complexity with energy codes such as ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings and U.S. Green Building Council’s LEED programs. Daylighting controls, occupancy/vacancy sensors with adaptive technology, astronomical timers, time-of-day shutoff, and multiple step-dimming lighting levels are some of the common lighting controls incorporated into building design and operation.
How does an engineer or commissioning agent commission these complex lighting controls? Fortunately, there are guidelines and processes: ASHRAE Guideline 0-2005: The Commissioning Process and ASHRAE Guideline 0-2013: The Commissioning Process; ASHRAE Standard 202-2013: Commissioning Process for Buildings and Systems; the ACG (AABC Commissioning Group) Commissioning Guideline; and IES DG-29-11: The Commissioning Process Applied to Lighting and Control Systems.
The IES Lighting Handbook, 9th Edition, defines commissioning of lighting systems as “a systematic process that ensures that all elements of the lighting control system perform interactively and continuously according to documented design intent and the needs of the building owner.”
Energy codes and LEED certification have made commissioning of lighting controls a requirement. ANSI/ASHRAE/IES Standard 90.1 requires functional testing of lighting controls and systems.
LEED Version 4 (the latest version of LEED) uses ASHRAE 90.1-2010 as the baseline energy code. Not only does Standard 90.1 require functional testing of lighting controls and systems, LEED Version 4 certification requires that lighting systems be commissioned. Functional testing is a core component of commissioning.
This discussion focuses on LEED Version 4 BD+C (Building Design and Construction). LEED BD+C applies to new construction and major renovation, core and shell, schools, retail, data centers, warehouses and distribution centers, hospitality, and health care.
LEED Fundamental Commissioning and Verification is an Energy and Atmosphere prerequisite; a project cannot be LEED Certified without meeting it. LEED defines the intent of Fundamental Commissioning and Verification to support the design, construction, and eventual operation of a project that meets the owner’s project requirements for energy, water, indoor environmental quality, and durability.
LEED requires that ASHRAE Guideline 0-2005 be used as the commissioning process. The LEED BD+C Reference Guide does not state the methodology to commission lighting systems. Fortunately, IES DG-29-11 is to be used as a supplement to ASHRAE Guideline 0-2005.
IES DG-29-11 includes requirements for lighting and control systems to fully support the commissioning process documentation, verification, and acceptance activities during each phase of the commissioning process, including a systems manual and training for operations and maintenance personnel and occupants.
LEED Enhanced Commissioning is an Energy and Atmosphere Credit. There are 2 to 6 points available for this credit, and they can be obtained via two options. The first option involves implementing Enhanced Systems Commissioning (3 to 4 points) by either going with Enhanced Commissioning (3 points) or Enhanced and Monitored-Based Commissioning (4 points). The second option requires envelope commissioning of the building.
It can be challenging to determine what is required as a project is seeking LEED certification and ASHRAE 90.1 compliance. IES DG-29-11 is a guide, and compliance with DG-29-11 is not listed as a requirement for LEED certification and ASHRAE compliance. See Table 1 for a comparison of the different standards and guides.
Design and occupancy
IES DG-29-11 breaks down the commissioning of lighting control systems into the following phases:
- Occupancy and operations.
The pre-design phase is when the commissioning team is formed and is led by the commissioning authority. The commissioning team, consisting of the construction manager, subcontractors, and designer, creates the commissioning plan, develops the owner’s project requirements (OPR), and provides procedures to identify and track issues during the commissioning process.
The OPR contains elements for design and should contain requirements for illumination. For example, a section of the 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. Daylight harvesting shall be utilized to achieve the required foot-candle levels.”
The OPR also states the design criteria to include goals such as the minimum level of LEED certification and sustainability goals. An example statement included in an OPR could state: “Project shall achieve a minimum of LEED Version 4 Silver Certification.”
The design phase includes the completion of the basis of design (BOD) that explains the concepts to achieve the OPR. For example, suppose the OPR states: “Vacancy sensors shall be used in all private enclosed offices.” A BOD to achieve this OPR may state: “Vacancy sensors utilizing passive infrared and ultrasonic, self-adaptive technologies shall be used in all private enclosed office. Sensors shall turn the lighting off within 5 minutes after an office is unoccupied.”
Typically, the design phase consists of schematic design, design development, construction documentation, construction administration, and final punch list.
The schematic design contains an outline of the lighting control system to fulfill the OPR. The design development phase includes detailed drawings and specifications.
Because lighting control strategies can be difficult for project stakeholders to ascertain, a diagram or drawing that explains the lighting control in each area/room can be of great benefit. Figure 1 shows a partial lighting plan that has been enhanced to illustrate the lighting control strategies for each space.
The construction documentation incorporates commissioning in the specifications. This includes lighting controls to be tested, and roles and responsibilities of the commissioning authority and the contractor(s). Including these items helps reduce or even eliminate conflicts and issues during commissioning tasks such as functional testing. For example, a commissioning specification may state, “The contractor shall notify the commissioning agent in writing at least 14 days in advance of all pre-functional testing.”
The commissioning authority reviews the lighting control design documents to check compliance with the OPR and the commissioning plan. For example, the commissioning authority may check that daylight sensors are located correctly (e.g., not obstructed by exposed ductwork). Another example includes verification that occupancy sensors are located more than 6 to 8 ft from HVAC diffusers (check manufacturer’s installation instructions). The commissioning authority typically notifies the design team of issues discovered during the review of the documents. The design team should then reply formally to the commissioning authority’s comments and resolve all issues.
The construction administration phase involves training of the facility personnel on the operation and maintenance of the lighting and control system. A good example of a training program includes explanation on how to temporarily override the lighting control system(s).
Confirming accurate design
Also included in this phase is performance testing. For lighting control systems, the commissioning authority, electrical contractor, operators, manufacturer representatives, and other stakeholders are typically present for the testing. A sample partial performance test for occupancy sensors may include verification that the electric lighting in a space turns on within 3 ft of entering a space in a private office.
The commissioning authority maintains an issues log that begins at the pre-design phase. The log includes details of each issue and who is responsible to resolve each issue one.
A systems manual, with specified sections provided by the construction manager, is handed by the commissioning team to the owner at the project turnover. The systems manual provides details, which are now described by LEED v4, on the operation and maintenance of the lighting controls. Also included are record drawings, submittals (shop drawings), the issues log, the OPR and BOD, as well as operations and maintenance manuals.
The occupancy and operations phase begins at substantial completion. This includes providing completion of any deferred testing and training as well as maintaining the systems manual.
The commissioning requirements of Standard 90.1-2010 require that the construction documents identify who will conduct and certify the testing. All specified lighting controls and associated software must be calibrated, adjusted, programmed, and assured to operate in accordance with construction documents and manufacturer installation instructions. Specific requirements are identified for occupancy sensors, programmable schedule controls, and photosensors.
For example, at a minimum, the party conducting the testing must confirm that the placement, sensitivity, and time-out settings for any installed occupancy sensors provide acceptable performance—for example, the lights must turn off only after the space is vacated, and must turn on only when the space is occupied. Time switches and programmable schedule controls must be programmed to turn the lights off. And photocontrol systems must reduce light levels produced by the electric lighting based on the amount of usable daylight in the space as specified.
Standard 90.1-2010 requires a commissioning authority that is not involved in the design or construction. The commissioning authority verifies that the lighting controls are adjusted, programmed, and functioning in accordance with the design and the manufacturer’s installation instructions. The commissioning authority then submits documentation certifying that the lighting systems are in compliance with or exceed the performance requirements.
Commissioning has many benefits, including reducing operational and maintenance costs. Commissioning of the lighting control systems is required by Standard 90.1-2010 and LEED. IES DG-29-11 in conjunction with ASHRAE Guideline 0-2005 provides the guidelines and process for a successfully commissioned lighting control system.
Michael Chow is the founder and owner of Metro CD Engineering. He holds a BSEE from Ohio Northern University and is a member of the Consulting-Specifying Engineer editorial advisory board and a 2009 40 Under 40 winner.