Specifying Lighting: What You Need to Know

by Samantha Ashenhurst | June 15, 2018 9:12 am

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by Terry Arbouw
The introduction of light-emitting diode (LED) fixtures has changed the established view of light sources. Best known for their ability to provide quality lighting with lowered energy costs, LEDs, in reality, represent a paradigm shift in the capabilities of a light fixture.

Prior to the introduction of LEDs, lighting fixtures for the most part were relatively simple devices providing a method of mounting a light source, generally a lamp, and a means of directing the light towards a task.

While they may appear similar to classic light fixtures, LED luminaires are, in fact, very different.

The LED fixture is a complex electronic circuit whose primary purpose, at first glance, is to simply illuminate indoor or outdoor spaces. These same circuits, however, can be easily expanded to exchange data, incorporate sensing technologies, or employ other technical assets. The LED lighting fixture—unlike many devices in today’s buildings—exists in some form to provide light to every usable square foot of a facility. They are everywhere. Therefore, LED lighting has the potential to become the primary location for the deployment of assets to monitor building environmental conditions and collect occupant information. There are a variety of applications already being considered and explored, including:

• indoor positioning;
• energy monitoring;
• asset tracking and management;
• occupant comfort and control; and
• space usage.

Additionally, LEDs have opened the door to innovative control capabilities, such as:

• low-cost dimming control (i.e. the ability to adjust intensity without the cost or complexity of dimming incandescent, fluorescent, or high-intensity discharge [HID] lighting);
• color temperature tuning (i.e. the ability to statically or dynamically adjust a lighting fixture’s color temperature to suit the needs of the occupant);
• circadian lighting whereby the color temperature of the lighting fixture is adjusted throughout the day to mimic the color changes produced by the sun; and
• full red, green, and blue (RGB) color changes, allowing for the selection of essentially any color in the rainbow.

The lighting industry is on the cusp of change as additional assets are beginning to appear on the fixture but are not yet mainstream.

Consider the typical office. Prior to LED lighting, the space would be outfitted with an occupancy sensor, and perhaps a switch to allow the tenant to manually turn on or off the lights. Today, it is becoming common practice to provide an occupant with not only on and off controls, but also the ability to reduce the lighting to a desired level without any of the complications involved in dimming fluorescent, HID, or even incandescent lamps. Fluorescent lighting, unlike LED, require special dimming ballasts costing on average $30 more than their non-dimming counterparts. Additionally, fluorescent lamps must be “burned in,” meaning they must run at 100 percent for 100 hours prior to being dimmed. Fluorescent ballasts and lamps have different dimming ranges—most go from 100 to 10 percent—while specialized ballast may dim as low as one percent. Fluorescent fixtures must be carefully designed to insure proper dimming, which is why they use a special dimming, non-shunted “tombstones” lamp connector located at the ends of each fixture the lamp plugs into. As fluorescent lamps age, its dimming performance is affected. Fluorescent lamps are also sensitive to temperature changes; cold air passing over the lamps from an air-conditioning system can affect dimming performance.

LED fixtures are fundamentally changing how an occupant interacts with the lighting in their space. Now occupants can adapt their visual environment to suit the task at hand. The byproduct of this functionality for building owners and operators is increased occupant satisfaction and productivity.

Drill deeper into a typical conference room or classroom setting, and one can see even more significant changes. In the past, lighting control capabilities such as user-controllable, preset lighting scenes and manual control were reserved for spaces that could justify the cost of a specialized architectural dimming system. Today, this functionality is mainstream and provided at a much lower cost with even more solutions. New capabilities such as color temperature controls are finding their way into classrooms, and healthcare and assisted living facilities.

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Perhaps the most attractive aspect of today’s LED fixtures is they are becoming more “connected.” A lighting fixture is essentially required to be anywhere people are within an enclosed space because one needs light to see. This establishes the luminaire as an attractive integration point for Internet of Things (IoT) as well as other assets.

Consider how a smartphone has not always been “smart.” At one point it was just a phone. As a personal communications device, it was always with us, making it the perfect gadget to attach additional assets like cameras, voice recorders, electronic day timers, alarm clocks, and music players. The phone had everything required for supporting and deploying additional assets. It had a battery and a way of recharging so it could supply power to other things. It was connected and it had a means of connecting to other things via cables, wireless, and even the Internet.

Similarly, LED luminaires have the required infrastructure to deploy additional assets. Luminaires are generally located above occupants with a clear view of where they are and what they are doing. They have a power supply (line mains or DC). They are becoming connected. In short, luminaires may well be the perfect location for tracking assets within a building (e.g. location of medical equipment, portable computers, testing equipment, or even people), location services, and wireless communications, as well as monitoring conditions such as air quality and gas-leak detection.

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Practical specification
Today’s lighting controls can be separated into two categories—centralized and distributed.

Centralized systems, as the name suggests, rely on a centralized controller to provide the intelligence required for managing the lighting within a space. Distributed systems, in contrast, work by distributing the control intelligence out to the device itself. In the author’s experience, the industry is moving toward distributed systems.

Centralized systems require messages from one device to first go to a controlling master or gateway before the signal can get to the target device. In this scenario, every communication between two non-master devices includes an extra step, or fault possibility. Distributed systems remove the single point of failures inherent in any centralized-control architecture and provide a much more scalable design.

Distributed systems allow for direct communication between two devices (unicast), from one device to many devices (multicast), or even from one device to all devices (broadcast). This is accomplished without a master device, thereby removing a potential performance bottleneck. In addition to enhanced system performance, distributed systems are much more fault-tolerant. A specific device failure affects only one fixture or device, and not the whole system, as would be the case in centralized-control architectures.

In distributed-control architecture, intelligent sensor devices are deployed within a space to monitor changes (e.g. occupancy and daylight) and receive input, such as the push of a button from a user who wants to change the lighting. The function of these devices is to simply monitor the space and broadcast the changes they receive. These devices themselves are not in charge of implementing the control strategy; this is the responsibility of “intelligent” lighting fixtures and other control devices. These devices make the decisions on how to best respond, and do so on their own, allowing for a highly scalable and robust system.

In a distributed intelligent system, specialized nodes (gateways) can be used to allow for the connection to other systems or applications either onsite or in the cloud. This is generally done through an application programming interface (API). Throughout the API, other applications and systems can be provided with monitoring, control, and programming capabilities.

Integration with BACnet
LED lighting is set for robust data collection. It is impossible to attend a connected lighting seminar without hearing about the communication possibilities and coverage of lighting and distribution for IoT over the building environment. BACnet (data communication protocol for building automation and control networks) was created in the 1980s to establish harmony among different building environmental systems with major emphasis on the HVAC industry and its components. Fast forward to today, the BACnet committee’s efforts focus on enhancing the data exchange within the BACnet standard for networked lighting systems, thereby opening the door for serious building management system (BMS) advantages enabled by LEDs and new lighting controls technologies.

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Wired, wireless, or both?
Deciding which system is best for the application can be overwhelming but there is some general guidance to keep in mind. If wiring can be easily run, a wired approach is best as it would reduce cost and provide the same functionality as a wireless system. However, if running cable between fixtures and controls would present issues such as may be found in an outdoor or warehouse application, wireless may be best. The choice is not always clear and sometimes a hybrid approach with a mix of wired and wireless systems is ideal.

In addition to issues related to cabling, consideration should also be given to the facility’s usage and potential for change. Systems requiring frequent reconfiguration or change may benefit from the additional flexibility offered by a wireless system.

There is no simple answer, so one must consider the options and select the system that best suits the desired outcome.

Power over Ethernet
Commercial building owners are increasingly enlisting the support of actionable intelligence for energy management and better building performance. Analytics (i.e. the process of turning data into actionable information) can have a significant impact on sustainability and cost-saving strategies. Power over Ethernet (PoE) solutions—scalable from basic lighting control to advanced cloud-based analytics—are in high demand because they are cost-effective for smart building deployments demanding an immediate return on investment (ROI).

The installation of PoE lighting solutions reduces material and labor costs by using a single Cat5e/6 connection for power and communication. Solutions offering modularity (i.e. the degree by which a system can be separated and recombined) offer a competitive advantage. The installation process is simplified by using a low-voltage cabling approach. The author has received feedback from facility owners who have seen tremendous advantages in having the flexibility to make infrastructure changes to support the evolving needs of real estate. Additionally, when customers go the low-voltage route, the lighting can be fixed by low-voltage installers, and it could be easily configured and reconfigured through software by IT personnel.

When evaluating PoE solutions, one must not overlook the importance of standards. Currently, industry standards are fluid and one may want to investigate and understand how the device input-output requirements are addressed by the solution.

One of the first things to do is to identify if the system is following the Institute of Electrical and Electronics Engineers (IEEE) 802.3, Standard for Ethernet. (For more, click here[5].) This standard allows for a “common road” to send data and links the wiring and network infrastructure. Applying this standard also ensures the PoE system is correctly connected to the corporate Internet to allow for data exchange with other systems.

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Color temperature tuning
In a recent American Institute of Architects (AIA) study[7], architects and building owners noted they are beginning to place greater emphasis on the impact of design decisions on human health. Nearly 75 percent of architects and 67 percent of owners said health considerations now play a role in how their buildings are designed, indicating healthy environments have become an important tool in marketing to faculty, students, and staff. Advances in lighting technology are having an impact on this trend.

Lighting manufacturers now offer the option of changing the color temperature of a luminaire to create various environments within a space. In the past, changing “scenes” within the same space would require multiple luminaire types with different color temperatures. This can now be accomplished with a single luminaire without sacrificing lumen output.

Know the codes
Any discussion about IoT includes data exchange. In buildings, the main protocol for data exchange between environmental systems is BACnet. The better a system conforms to the BACnet standard, the better the exchange. Specifiers should become familiar with the American National Standards Institute/American Society of Heating, Refrigerating and Air-conditioning Engineers (ANSI/ASHRAE) 135, BACnet – A Data Communication Protocol for Building Automation and Control Networks. One can browse the entire 1600-plus page standard, but the author suggests designers and specifiers pay close attention to Clause 22 discussing product conformance with the BACnet standard. Topics include minimum requirements, proper documentation, and testing. Many systems claim to have BACnet integration, but if they do not conform to Clause 22, it will most certainly be lacking in capability and, ultimately, lead to disappointment.

Another code of particular importance is ANSI C137.3, Lighting Systems – Minimum Requirements for installation of Energy Efficient Power over Ethernet (PoE) Lighting Systems. IEEE 802.3 allows for more than 15 percent loss from the power supply to the luminaire but the new ANSI C137.3 limits the loss to five percent. The main item is category wiring and the evolution towards thicker gauges. Network wiring traditionally focused on transmission speed. The new focus is on decreasing energy loss.

Emergency lighting is still regulated by National Electric Code (NEC) 700, Emergency Systems, and any PoE lighting specification needs to meet this standard, especially 700.24, which discusses directly-controlled luminaires.

What is the best approach for a specifier given the current state of LED luminaires technology?

This would appear to be a difficult question because of all the available options. However, when broken down, the process can be quite simple. Some points the specifier should consider are:

• what is the intended usage of the space;
• what are the expectations and desired interactions of the building occupant;
• how connected does the system need to be and where do the decisions need to be made; and
• what codes need to be met?

Cost can also be a factor. It is important to consider carefully initial vs. long-term costs. Foregoing lighting controls of any kind may save initial cost. However, over the life of the building, the cost associated with needlessly wasted energy due to the lack of control would outweigh the cost of installing controls. While it may be difficult to assign a monetary value to occupant comfort and overall satisfaction, these are important aspects of a well-executed lighting system.

Terry Arbouw is director of business development and product innovation at Hubbell Control Solutions. He has more than 38 years of experience in the lighting controls industry. Arbouw has held many roles including product engineering and management, system design and architecture, marketing, and sales. Arbouw is a graduate of Confederation College of Applied Arts & Technology and has been awarded six U.S. patents. He can be reached via e-mail at tarbouw@hubbell.com[8].

Source URL: https://www.constructionspecifier.com/specifying-lighting-what-you-need-to-know/

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