Your questions answered: Lighting controls

The Aug. 16, 2018, lighting controls webcast presenters addressed questions not covered during the live event.

By Sara Lappano, PE, LC, LEED AP; and Michael Chow, PE, CEM, CxA, LEED AP BD+C August 23, 2018

Codes and standards require lighting engineers to include power allowances, daylighting controls, functional testing, and commissioning in lighting designs to verify lighting controls. Requirements for lighting controls become more complex with each edition of the energy-conservation codes. Codes and standards include ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings, the International Energy Conservation Code (IECC), and California Title 24. This webcast summarizes the codes and standards that apply to lighting systems, controls, and commissioning. It also reviews the different approaches to the controls that meet energy-efficiency requirements.

Presenters Sara Lappano, PE, LC, LEED AP, Integral Group, Washington, D.C.; and Michael Chow, PE, CEM, CxA, LEED AP BD+C, Metro CD Engineering LLC, Columbus, Ohio, responded to questions not answered during the live Lighting controls webcast on Aug. 16, 2018.

Question: What type of drivers are used for 100 W T8 equivalent LED lamps?

Sara Lappano: Generally, LED lamp manufacturers can provide feedback on specific LED drivers that are compatible with their lamps. Note that not all drivers are capable of dimming. Some are only able to do on/off switching.

Q: Please discuss integration of lighting controls into a building automation system and lighting controls working in conjunction with light harvesting strategies.

Michael Chow: Please refer to the presentation case study for the University of Toledo Larimer Athletic Complex remodel. In this case study, the yellow highlighted area has lots of windows with daylighting harvest sensors to dim the LED lighting fixtures in this area. The low-voltage relay panel lighting controller/building automation system (BAS) will turn off the lighting fixtures in this area via a time-scheduled shutoff. There is a manual override (not shown) through the panel/BAS that will provide 30 minutes of lighting in the space after the shut-off period. The lighting fixtures will flash 5 minutes before the 30-minute period is up so the override button can be pushed to reset the timer to 30 minutes. The 30-minute period is governed by the lighting code that only allows a maximum 30-minute manual override.

Q: Can a time clock be used in place of occupancy sensors?

Lappano: The energy codes indicate space types where occupancy sensors are required. In these space types, occupancy sensors must be used and time clock control is not acceptable. In spaces that are not listed as requiring occupancy sensors, either a time clock or occupancy sensors can be used to meet the automatic control requirements.

Q: Please discuss recommended commissioning and pitfalls.

Chow: The biggest commissioning recommendation is involving the commissioning authority/agent at the onset of the project at the predesign level. The commissioning authority will be able to do design reviews and potentially catch something that may not be designed correctly. For example, a passive infrared (PIR) occupancy sensor in a large, multi-stall restroom would not work well due to the sensor not being able to “see” through or around the stall walls. A dual-technology sensor (PIR and ultrasonic) would be a better choice for this restroom.

Another recommendation is to include commissioning in the specifications and also in the contractor’s contract and scope of work. This will help avoid change orders for commissioning and the contractor may claim commissioning assistance and coordination were not in their contract.

During lighting commissioning, it is important to have the lighting designer, the commissioning authority, the electrical/lighting contractor, and the factory startup representative present for functional testing. This helps eliminate finger-pointing if one party is not present.

Another recommendation is to video record the training for lighting operations and maintenance for facility staff. This has been a big help in reducing the number of follow-up visits, problems, etc.

Q: How do I determine whether I’m required to follow the energy code for a project, either in terms of minimum square footage or level of renovation?

Lappano: This information sometimes can be difficult to find. Similar to the way that local jurisdictions adopt individual energy codes, it also is typical that local jurisdictions dictate what types of projects and renovations must follow certain energy codes. So, I recommend first checking the building code requirements of the jurisdiction you’re in because that often lists which codes must be followed for different types of projects. In addition, the IECC provides some guidance on this in Chapter 1, Scope and Administration, and Chapter 2, Definitions (where it defines what qualifies as a residential versus a commercial building). Chapter 5, Existing Buildings, provides some useful detail on the level of alterations that requires the IECC to be followed, including lighting alterations. ASHRAE 90.1, Chapter 2, Scope, provides some general guidance on when the code should be applied. Chapter 4, Administration and Enforcement, provides some additional details.

Q: Which is the big umbrella, IECC or ASHRAE?

Lappano: IECC and ASHRAE 90.1 are comparable because they provide requirements for similar aspects of buildings that affect energy usage (envelope, water heating, HVAC, lighting, etc.). IECC is more widely adopted than ASHRAE, but because IECC allows ASHRAE 90.1 to be used as an alternate compliance path, both the IECC and ASHRAE 90.1 are comparable in terms of their application.

Q: How do you interface lighting occupancy sensors to control HVAC?

Chow: This typically is done through the lighting occupancy sensor sending a signal when there is occupancy or no occupancy to the HVAC direct digital control (DDC) system. A sequence of operations should be provided with the HVAC and lighting contract documents (drawings, specifications, etc.) that explains exactly how the two systems should interface. The reason to put this on both HVAC and lighting contract documents is because usually the HVAC and electrical contractors do not get both sets of documents. The HVAC controls contractor should program the DDC system to control the HVAC through the occupancy sensors.

Q: What control components do we include to allow the higher wattage under the ASHRAE/IECC codes/standards?

Lappano: The IECC does not allow higher installed lighting wattage based on what controls are being used. ASHRAE 90.1, however, does provide some instances where certain types of lighting controls allow higher lighting power densities. Chapter 9, Lighting, section 9.6.3 Additional Lighting Power Using Nonmandatory Controls outlines instances where this is allowed.

Q: Where can we find the case study on the receptacle occupant automatic control analysis?

Lappano: There is a hyperlink on the slides containing information from the study.

Q: How can we automatically and properly shut down workstations before cutting the power?

Chow: A procedure should be implemented on how workstations are to be shut down before the power is removed through a time-of-day shutoff. Some clients require workstations to be left on during the evenings so virus scans, maintenance, etc. can be done. In this case, it is not recommended to control the power to the workstation through a controlled time-of-day receptacle. However, monitors and/or printers can be shut off if not needed after-hours with the time-of-day receptacle control.

Q: What about the owners who aren’t sophisticated and don’t have high-tech maintainers? How do you sell this technology to them? For example, senior living facilities that have administrative spaces.

Lappano: Provided these systems are initially set up and commissioned properly, the controls should be fairly automatic and low maintenance. The energy codes have advanced quickly over the past several years, so new buildings and spaces constructed today have more advanced controls than even 5 years ago. Communication with the client during design and designing the systems to be as automatic and intuitive as possible will help with this transition.

Q: Who is responsible for the lighting commissioning? Usually is it done by the lighting manufacturer, or by the electrical contractor who purchases and installs the system?

Chow: I recommend an independent commissioning agent be hired for the commissioning of the lighting control systems. This person would not be involved with the design or installation of the lighting system. A factory start-up is not the same as commissioning. A commissioning agent (or authority) should be contracted directly with the owner and look out for the owner’s best interests. The commissioning agent would document the factory startup of lighting controls to ensure the process was done properly. The electrical contractor should not do the commissioning as this is a conflict of interest. There may be some unscrupulous contractors that forge the commissioning reports even though there are unresolved issues so they can get paid. An independent commissioning agent working and contracted through the owner could prevent an electrical contractor getting paid in full until all issues are resolved.

Q: What is IECC?

Lappano: IECC stands for the International Energy Conservation Code.

Q: Please explain exactly what commissioning is.

Chow: See the presentation for the IES definition. Commissioning essentially is making sure the energy-efficient controls and systems that are installed are working properly.

Q: With all of these automatic controls, are there standard provisions for override by emergency responders?

Lappano: The ability to control/shut off egress lighting varies by jurisdiction, and I’ve seen a variety of preferences by the authority having jurisdiction (AHJ) on this topic. I should note that, generally, exit signs remain on at all times. Even in cases where the AHJ does allow control of egress lighting, it always is required to automatically turn on to full brightness during a power outage to ensure safe evacuation of building occupants by code. Generally, because egress lighting is a life safety issue, the requirements of the local jurisdiction will override what the standard version of the code or standards allow.

Q: Please discuss photopic versus scotopic light level measurements in Cx.

Chow: Generally, photopic and scotopic light levels are only commissioned if the owner’s project requirements (OPR) call for this. The commissioning agent/authority would need a light meter that can read both photopic and scotopic light levels. The meter should be calibrated ideally within the last 3 to 6 months.

Q: I’m a city building official and recently our city required a new apartment complex to be LEED certified in our city ordinance. My question is, since it is mandatory by ordinance instead of optional, what is my role as the building official in the LEED process? What documents, inspection, or updates should I require? Proof of compliance reports?

Lappano: The U.S. Green Building Council, which administers LEED, has a fairly robust process for providing documentation of each LEED perquisite and credit that is being pursued. Once a project team has successfully completed this documentation and it meets the approval of the LEED reviewer(s), the project is then awarded whatever level of LEED certification corresponds to the number of points it has achieved, so this should be a fairly straight-forward way to verify it, although the certification normally is awarded after completion of the project.

Q: How much success have you had executing OPRs (especially for lighting systems)? Are there templates available. Who typically creates the OPR? Commissioning provider or owner?

Chow: A good template can be found here:

My opinion is the owner should develop the OPR. The commissioning authority (CxA) can assist with this as well as the architecture engineering (A/E) team. The CxA should review the OPR and ensure the basis of design (BOD) aligns with the OPR.

Q: What is your experience of cost premiums for receptacle power controls?

Lappano: There certainly is a cost premium, but it’s hard to quantify because there are so many different ways to comply with the code. For example, if you have a lot of private offices, the switched receptacles in each of them could be controlled individually based on whether the office is occupied, or they all could be switched on/off together based on timeclock controls. Generally, the receptacles piggyback onto the local occupancy sensor control, so the cost is generally either an additional or upgraded controller/power pack that controls both lighting and receptacles, as well as some additional branch circuit wiring if you have a mixture of switched and unswitched receptacles.

Q: As the design engineer, how often do you review the final commissioning reports? Do you require this?

Chow: Design engineers should review the final commissioning reports. They usually are copied on the distribution of the final commissioning report. A properly commissioned project has the commissioning authority (CxA) contracted directly for the owner and engaged at the predesign phase. The design engineers are working with the CxA throughout the design process. The CxA also reviews (but does not approve) shop drawings and submittals. The commissioning process consists of a team and the CxA and design engineers are both involved throughout the entire project.

Q: Regarding T24, we’ve been doing plug loads in California. Glad to see that ASHRAE also has this included in 90.1. Do you see the rest of the country improving (getting better) for lighting controls based on the clients and also regulatory agencies?

Lappano: While there are certainly owners/clients who are driving a demand for more advanced lighting/plug load controls, I see states and local jurisdictions being the major driver. As the latest energy codes and standards (which continue to drive down energy use) get adopted by local jurisdictions, we have seen much more widespread application of more advanced controls like plug-load control.

Q: When you split the receptacles into one switched and the other unswitched, do you need to count each half as 180 VA for code calculations?

Lappano: NFPA 70-2017: National Electrical Code (NEC) treats duplex receptacles the same regardless of whether they are fully or partially switched. Therefore, for the purpose of electrical load calculations, no change is needed in terms of what load is assigned to each receptacle.

Q: What is the marking requirement for automatically controlled receptacles?

Lappano: NEC Article 406.3(E) lists the requirements for marking controlled receptacles. It notes that each controlled outlet should be indicated with a symbol they provide (it looks like an on/off symbol) as well as the word “Controlled.”

Q: Some receptacles are for after-hours maintenance use. Are these able to be resolved with the 50% control requirement? Is that a design/predesign issue?

Lappano: Even for receptacles that are switched, there should be some means to turn them on when occupants are present. If occupancy sensors are used for plug load control, then it’s fairly simple because the receptacles will turn on any time occupancy is detected (this would work for after-hours maintenance). Alternatively, if time-clock control is used, an override switch would need to be provided, which would be needed to energize receptacles outside of core operating hours. Also, since the requirement is for 50% of receptacles to be controlled, engineers can decide during the design process which receptacles are switched versus unswitched.