NEMA LSD 76-2017 White Paper on the Usage of LED Lamps in Emergency Lighting Systems Having Remote Capacity.pdf

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1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA LSD 76-2017White Paper on the Usage of LED Lamps in Emergency Lighting Systems Having Remote CapacityNEMA LSD 76-2017 Page 1 2017 National Electrical Manufacturers Association. A NEMA Lighting Systems Division Document LSD 7

2、6-2017 White Paper on the Usage of LED Lamps in Emergency Lighting Systems Having Remote Capacity Prepared by NEMA Emergency Lighting Section National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 The requirements or guidelines presented in this docum

3、ent, a NEMA Lighting Systems Division white paper, are considered technically sound at the time they are approved for publication. They are not a substitute for a product sellers or users own judgment with respect to the particular product discussed, and NEMA does not undertake to guarantee the perf

4、ormance of any individual manufacturers products by virtue of this document or guide. Thus, NEMA expressly disclaims any responsibility for damages arising from the use, application, or reliance by others on the information contained in these white papers, standards, or guidelines. The opinions expr

5、essed in this statement represent the consensus views of the member companies of the Lighting Systems Division of the National Electrical Manufacturers Association. The members of the Lighting Systems Division manufacture traditional technology lamps and ballasts, light-emitting diodes (LEDs) and or

6、ganic light-emitting diodes (OLEDs), LED lamps and modules, LED drivers and power supplies, luminaires, lighting controls and management systems. 2017 National Electrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright Convent

7、ion, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions. NEMA LSD 76-2017 Page 2 2017 National Electrical Manufacturers Association. Foreword In the preparation of this standards publication, input of users and other i

8、nterested parties has been sought and evaluated. Inquiries, comments, and proposed or recommended revisions should be submitted to the concerned NEMA product subdivision by contacting the: Senior Technical Director, Operations National Electrical Manufacturers Association 1300 North 17thStreet, Suit

9、e 900 Rosslyn, Virginia 22209 NEMA LSD 76-2017 Page 3 2017 National Electrical Manufacturers Association. CONTENTS What is remote capacity in an emergency lighting system? . 4 Can more LED remote heads work with traditional emergency equipment having remote capacity? . 4 Why cant someone just design

10、 an LED-based emergency unit? 5 Is it possible to design a self-ballasted LED lamp? 5 NEMA LSD 76-2017 Page 4 2017 National Electrical Manufacturers Association. What is remote capacity in an emergency lighting system? Emergency battery units, exit signs, or combination exit/emergency battery units

11、with remote capacity provide a means for delivering energy to additional emergency lighting equipment such as stand-alone luminaires or lamp heads (commonly called remotes), emergency signage, or other emergency lighting equipment during power outages. In general, any combination of remote lamp head

12、s and other equipment may be added to the system as long as the total wattage does not exceed the rated wattage capacity of the source unit. Because the lighting industry has had several decades to standardize specific voltages using traditional battery voltage characteristics, most incandescent eme

13、rgency battery units offer 6 V24 V voltage outputs, which match their respective standardized incandescent lamp input voltages. As new technologies are introduced in batteries and in light-emitting diode (LED) engines there is a greater variety of voltages offered for the application. Example: an em

14、ergency battery unit offering two 7.2 watt integral lamp heads is rated at 80 watts capacity. Already using 14.4 watts to power its integral lamps, the emergency battery unit then has 65.6 watts of remaining remote capacity. Any combination of remote lamp heads and exit signs may be added up to the

15、65.6 watts of remote capacity as long as the standardized voltages match-up between the source and the load. Additional batteries, or higher capacity batteries, are required to energize remote emergency lighting devices in addition to what is necessary to illuminate the integral load. Utilizing remo

16、te capacity, as opposed to providing multiple individual stand-alone emergency battery units, might represent a more efficient and cost effective way of providing emergency lighting throughout a building and/or to the outside of the building. Can more LED remote heads work with traditional emergency

17、 equipment having remote capacity? It would seem natural to assume that remote heads equipped with LEDs would typically consume less energy for a given amount of light output than incandescent lamp equipped remote heads. LED remote heads typically provide energy cost savings in normally-on, non-emer

18、gency lighting. One would genuinely presuppose utilizing LED remote heads in emergency lighting would translate into either realized energy savings or the ability to illuminate an increased number of LED remote heads using the same battery unit. Also, one could easily meet the capacity requirements

19、noted in the example above by using lower-wattage LED remote heads. The short answer to this question is two-pronged: a lack of standardization of input voltage and a lack of control over the input current. A basic understanding of lamp technology will clarify. Creating a basic circuit consisting of

20、 an incandescent lamp, wires, an on/off switch and a battery for power may bring back fond memories of grade school science class. An old flashlight works in the same mannerthe power from the battery can be connected directly to the lamp and controlled via an on/off switch. In an emergency lighting

21、unit, an electronic circuit detects the presence, or absence, of AC line voltage. When the loss of AC voltage is detected, it then activates the switch allowing DC power to flow from the battery directly to the lamp(s). This system works because an incandescent lamp accepts a relatively wide range o

22、f non-controlled current and because the battery units output voltage matches a standardized range of lamp input voltages. Of course, incandescent lamps will brighten and dim at varying input voltages within the range. NEMA LSD 76-2017 Page 5 2017 National Electrical Manufacturers Association. Most

23、non-incandescent lamp types (High-intensity discharge, fluorescent, compact fluorescent lamp, etc.) require controlled voltage and/or controlled current to operate within their design parameters. For example, a fluorescent lamp cannot be connected directly to a power source as they require a ballast

24、 to initiate, and then stabilize, the flow of current. During lamp starting, the ballast must briefly supply high voltage to establish an arc between the lamps two electrodes. Once the arc is established, the ballast quickly reduces the voltage and regulates the electric current to produce a steady

25、light output. Without the fluorescent ballast, a fluorescent lamp connected directly to a power source would rapidly, and uncontrollably, increase its current draw until it was destroyed or caused the power supply to fail. Similarly, LEDs require a regulator (or driver) to control the voltage and cu

26、rrent. Without it, the LEDs would blow just like a fuse receiving too much current. In addition, because LEDs are a relatively new technology that has recently become main stream within the lighting industry, there hasnt been enough time to develop standardized input voltages. To complicate matters,

27、 many LED lamps use an array of LEDs to provide the desired amount of lumens which only exacerbates the non-standard input voltage issue. Why cant someone just design an LED-based emergency unit? There are actually several LED-based emergency units on the market today, but they are often designed to

28、 work with a specific set of LED remote heads. Because the lighting market has not established standards, an LED requires a specific driver to operate its corresponding lamp head(s) properly. The driver may be located either in the emergency unit itself or in the lamp head. When space and/or heat co

29、nstraints exist inside a lamp head, the driver is designed into the emergency battery unit itself. Is it possible to design a self-ballasted LED lamp? It is possible to design a self-ballasted LED lamp to operate on a relatively wide range of input voltages (e.g. 6 V12 V) and universal LED lamps can

30、 be found on the market today. When designed correctly, LED lamps can offer greater energy savings, increased performance and better light control, so there is an advantage to using this technology. The driver of self-ballasted lamps is located inside the lamp itself. Typically, the performance char

31、acteristics of these lamps are limited by space and heat. Because of their flexibility, these lamps will work with traditional (incandescent) emergency lighting units. In general, self-ballasted LED lamps are much more sensitive to the input voltage and current than incandescent lamps. For an incand

32、escent lamp, a slight drop in input voltage below its minimum rated operating voltage will most likely result in only a degradation of lumen output. The same conditions for a self-ballasted LED lamp may possibly result in either no lumen output or increased current draw on the batteries. Because of

33、their sensitivity, LED lamps require a more regulated input of both voltage and current. This regulation may not have been designed into the emergency battery unit that was developed for incandescent technology. Each self-ballasted LED lamp must be tested to ensure its compatibility with the emergen

34、cy battery unit. Another important consideration is maintaining the UL924 listing of the original emergency lighting equipment. The self-ballasted LED replacement lamp would need to be recognized as a suitable replacement light source in emergency lighting applications. NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION 1300 NORTH 17TH STREET, SUITE 900 ROSSLYN. VA 22209www.NEMA.orgTO ORDER ADDITIONAL NEMA STANDARDS VISITWWW.GLOBAL.IHS.COM OR CALL 1-800-854-7179/1-303-397-79565612_0514TB