1、IES LM-37-16IES Approved Method IES Guide for Determination of Average Luminance (Calculated) for Indoor LuminairesIES LM-37-16IES Guide for DeterminationofAverage Luminance (Calculated) for Indoor LuminairesPublication of this LMhas been approved by IES.Suggestions for revisionsshould be directed t
2、o IES.Prepared by the Photometry of Indoor Luminaires Subcommitteeof the IES Testing Procedures CommitteeIES LM-37-16Copyright 2016 by the Illuminating Engineering Society.Approved by the IES Board of Directors, October 23, 2014, as a Transaction of the Illuminating Engineering Society of North Amer
3、ica.All rights reserved. No part of this publication may be reproduced in any form, in any electronic retrieval system or otherwise, without prior written permission of the IES.Published by the Illuminating Engineering Society of North America, 120 Wall Street, New York, New York 10005.IES Standards
4、 and Guides are developed through committee consensus and produced by the IES Office in New York. Careful attention is given to style and accuracy. If any errors are noted in this document, please forward them to Brian Liebel, Director of Technical Standards, at the above address for verification an
5、d correction. The IES welcomes and urges feedback and comments. ISBN # 978-0-87995-333-1Printed in the United States of America.DISCLAIMERIES publications are developed through the consensus standards development process approved by the American National Standards Institute. This process brings toge
6、ther volunteers representing varied viewpoints and interests to achieve consensus on lighting recommendations. While the IES administers the process and establishes policies and procedures to promote fairness in the development of consensus, it makes no guaranty or warranty as to the accuracy or com
7、pleteness of any information published herein.The IES disclaims liability for any injury to persons or property or other damages of any nature whatsoever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use of, or reliance on this docu
8、ment.In issuing and making this document available, the IES is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is the IES undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his
9、 or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances.The IES has no power, nor does it undertake, to police or enforce compliance with the contents of this document. Nor does the IES
10、 list, certify, test or inspect products, designs, or installations for compliance with this document. Any certification or statement of compliance with the requirements of this document shall not be attributable to the IES and is solely the responsibility of the certifier or maker of the statement.
11、IES LM-37-16Prepared by the Photometry of Indoor Luminaires Subcommittee of the IES Testing Procedures CommitteeMichael Grather, Sub-ChairDavid Randolph, Vice ChairIES Testing Procedures CommitteeC. Cameron Miller, ChairBecky Kuebler, Vice ChairDavid Ellis, SecretaryJianzhong Jiao, TreasurerP. Behnk
12、e*R. BergerR. BerginE. Carter*D. Chan*G. Connelly*P. Franck*C. Galberth*T. Henning*J. HospodarskyP. JasterT. Kawabata*TY. Koo*B. KueblerJ. Leland*K. Lerbs*R. Levin*I. Lewin*S. LongoP. McCarthyC. Cameron MillerS. Patel*M. Piscitelli*D. Randolph*B. Rao*J. Swiernik*H. Waugh*J. Welch*V. Wu*R. Young*J. Z
13、hangC. AndersenL. Ayers*A. Baker*P. Behnke*R. BergerR. Bergin*R. BergmanJ. C. Blacker*C. Bloomfield*E. BretschneiderK. Broughton*E. Carter*D. Chan*P-T. Chou*G. Connelly*J. Dakin*R. Daubach*L. Davis*J. Demirjian*P. Elizondo*P. Franck*M. GratherY. Guan*K. Haraguchi*R. Heinisch*K. Hemmi*T. Henning*T. H
14、ernandez*R. Higley*R. Horan*J. HospodarskyS. Hua*J. HulettP-C. HungD. Husby*A. Jackson*D. Jenkins*D. Karambelas*H. Kashani*T. Kawabata*R. Kelley*T.Y. Koo*M. KotrebaiJ. Lawton*J. Lee*L. Leetzow*J. Leland*K. Lerbs*R. Levin*I. Lewin*R. Li*K. Liepmann*S. LongoR. Low*M.-H. Lu*J. MarellaP. McCarthyG. McKe
15、eM. Minarczyk*Z. Mooney*F.-X. Morin*M. Nadal*D. Nava*B. Neale*Y. Ohno*J. Pan*D. Park*N. Peimanovic*E. Perkins*M. Piscitelli*G. Plank*E. RadkovD. Randolph*C. Richards*E. Richman*K. Rong*M. SapcoeJ. SchutzA. Serres*A. SmithR. Speck*L. Stafford*G. SteinbergR. TuttleT. Uchida*K. Wagner*J. Walker*H. Waug
16、h*D. Weiss*J. Welch*K. Wilcox*B. Willcock*V. Wu*J. YonR. Young*J. Zhang* Advisory Member* Honorary MemberIES LM-37-16IES LM-37-16Please refer to the IES Bookstore after you have purchased this IES Standard, for possible Errata, Addenda, and Clarifications, www.ies.org/bookstore.ContentsIntroduction.
17、11.0 Scope .12.0 Normative References13.0 Nomenclature and Definitions .13.1. AB13.2. ABP 13.3. angle (vertical viewing angle)13.4. angle (horizontal viewing angle) .13.5. AS13.6. ASP.13.7. Average luminance (Calculated) .13.8. D .13.9. H .23.10. L, W 23.11. Total projected luminous area (at viewing
18、 angle ) .24.0 General method of calculation of average luminance (Calculated) .24.1. Circular Luminaire Openings (Open Bottom or Flat Lens) .24.2. Circular Luminaire Openings with Drop Lenses 24.3. Square or Rectangular Luminaire Openings (Open Bottom or Flat Lens) .34.4. Square or Rectangular Lumi
19、naire Openings with Drop Lenses .34.5. Irregularly Shaped or Polygonal Openings for Luminaires .34.6. Projected area formula for luminous opening types defined in LM-63 .54.6.1. Point 54.6.2. Rectangular.54.6.3. Rectangular with Luminous Sides54.6.4. Circular 54.6.5. Ellipse .54.6.6. Vertical cylind
20、er 54.6.7. Sphere.54.6.8. Horizontal cylinder along photometric horizontal 54.6.9. Horizontal cylinder perpendicular to photometric horizontal 64.6.10. Vertical circle facing photometric horizontal 64.6.11. Vertical ellipse facing photometric horizontal .64.7. Surfaces with multiple light emitting o
21、penings.6Annex A - Representative Area Formulas Reference (not all-inclusive) .7A.1 Circular Luminaire Opening (Open Bottom or Flat Lens) .7A.2 Circular Luminaire Openings with Drop Lenses (Truncated Cone) .7A.3 Square or Rectangular Luminaire Openings (open bottom or flat lens) .9A.4 Square or Rect
22、angular Luminaire Openings with Drop Lenses.11A.5 Spherical Lens .11References (for Annex A) 13IES LM-37-161IES LM-37-16IES Guide for Determination of Average Luminance (Calculated) for Indoor LuminairesINTRODuCTION The concept and limitations of average luminance is addressed in this Guide. Althoug
23、h simple projected area examples are presented and more detailed area calculation methods are developed for refer-ence purposes in Annex A, it remains the users responsibility to seek out the most appropriate methods/formulas each time he/she determines the actual projected areas for a specific lumi
24、naire. 1.0 SCOPE The methods of calculating average luminance contained in this Guide cover various open bottom apertures as well as flat and drop lensed units, including units with multiple openings in the light emitting area. The candela values of interest are obtained by means of IES techniques f
25、or relative or absolute photometry, and are not obtained from field measurements in application. Note: Average lumi-naire luminance is not a reliable indicator of either direct or reflected glare due to potential luminance non-uniformity. The averaging of data from spot luminance mea-surements obtai
26、ned with luminance meters or high resolution imaging systems is not within the scope of this document. This calculation is based solely on the candela values obtained by goniometric measurement of the luminaire and the luminous projected area. All light sources, for which there are current stan-dard
27、s for luminaire photometry, are covered by this Guide. These include incandescent, fluorescent, high intensity discharge (HID), low pressure sodium, and LED sources. 2.0 NORMATIVE REFERENCESANSI / IES RP-16-10, Nomenclature and Definitions for Illuminating Engineering. Illuminating Engineering Socie
28、ty of North America. New York, NY.3.0 NOMENCLATuRE AND DEFINITIONS3.1 ABThe luminous area of the bottom of a lens case, measured in square meters (preferred) or square feet, viewed from nadir. 3.2 ABP The projected luminous area of the bottom of a lens case as viewed from angle from nadir, measured
29、in square meters (preferred) or square feet. 3.3 angle (vertical viewing angle) This angle is expressed in degrees as measured from nadir. It is the angle at which the area projec-tions are calculated, and at which the appropriate luminaire intensity (cd) is selected for average lumi-nance calculati
30、ons. 3.4 angle (horizontal viewing angle) The lateral position from a beginning reference posi-tion, from which performance information is evalu-ated. 3.5 AS The luminous area of the side of a drop lens case, measured in square meters (preferred) or square feet, viewed from 90 degrees vertical. 3.6
31、ASP The projected luminous area of the side of a drop lens case, measured in square meters (preferred) or square feet, as viewed from angle from 90 degrees vertical.3.7 Average luminance (Calculated)The average luminance of a luminaire based on the candela value obtained from a goniometric mea-surem
32、ent and the projected luminous area of the luminaire at that measurement angle.Equation (1)3.8 D The luminaire lens or opening diameter in meters (preferred) or feet. 2IES LM-37-163.9 H The luminaire lens height in meters (preferred) or feet. 3.11 L, W The rectangular luminaire lens or opening dimen
33、-sion (length, width) expressed in meters (preferred) or feet. 3.12 Total projected luminous area (at viewing angle ) The sum of the bottom and side luminous projected areas (for a given luminaire lens or opening) as viewed from angle at a given horizontal angle .4.0 GENERAL METHOD OF CALCuLATION OF
34、 AVERAGE LuMINANCE (CALCuLATED)The equation used to determine average luminance as used in this Guide is:Equation (2)where: angle is the viewing angle in degrees (see definitions)luminous intensity at angle is in candelas projected luminous area at angle is in m2average luminance (calculated) is exp
35、ressed in cd/m2Metric (SI) units (as just shown) are preferred, although it is recognized that individual circum-stances may require that the equation be implement-ed in the following Imperial System version: Equation (3)where: angle is the viewing angle in degrees (see definition) luminous intensit
36、y at angle is in candelasprojected luminous area at angle is in ft2average luminance (calculated) is expressed in candelas/ft2Note: Earlier methods, and even some of todays literature, express luminance in “footlamberts“ (fL), a lambertian unit of luminance that equals 1/cd/ft2. This terminology is
37、obsolete and actually repre-sents a -multiple of luminance as calculated in the Imperial System. It is often presented as:Equation (4)where: angle is the viewing angle in degrees (see definition) luminous intensity at angle is in candelas projected luminous area at angle is in ft2average “luminance“
38、 is in footlambertsThe examples immediately following in Section 4.1 through 4.6 are useful to clarify the quantities involved, giving examples of projections of luminous areas of luminaires. For more complex shapes, please refer to Annex A for calculation methods.Caution: These calculated average l
39、uminance results are best suited to describe emitter sources that are uniformly diffuse, and do not accurately convey the comfort level of non-uniform luminance distributions. Misleading conclusions can be reached regarding com-fort or glare comparisons between products, especially with clear source
40、s and/or specular reflector surfaces. 4.1 Circular Luminaire Openings (Open Bottom or Flat Lens) For flat lensed or open bottom luminaires as illustrat-ed in Figure 1, the equation for projected luminous area at angle is:Equation (5)where: ABP is the projected luminous area at angle AB is the lumino
41、us area at 0 degrees D is the diameter of the luminous area 4.2 Circular Luminaire Openings with Drop Lenses For drop lens circular luminaires (see Figure 2), the sides of the lens shall be considered in the total projected luminous area calculations. The total pro-jected luminous area at angle equa
42、ls ASP + ABP, where ASP is the projected side luminous area as viewed at angle (use appropriate formula for given 3IES LM-37-16geometry), and: Equation (6)where: ABP is the projected bottom luminous area as viewed at angle AB is the bottom luminous area at 0 degreesD is the diameter of the luminous
43、area A simple, straight (vertical) side drop lens would have a side projected area .4.3 Square or Rectangular Luminaire Openings (Open Bottom or Flat Lens) For square or rectangular luminaire openings (see Figure 3), use an appropriate projected area formula for a given geometry. Each unique situati
44、on shall be assessed and a faithful mathematical representation of the projected areas found. Candela values used in the luminance calculation shall be taken at the horizontal angle of interest. The area projection cal-culation shall be made at this same horizontal angle. 4.4 Square or Rectangular L
45、uminaire Openings with Drop LensesThis case, of a square or rectangular luminaire opening with a drop lens (see Figure 4), is more complex than the flat lens/open bottom situation due to the fact that the amount of luminous side area in the drop portion of the lens changes with both hori-zontal and
46、vertical viewing angles. For a luminaire side (viewing the length dimension) use the formula: total projected luminous side area = ASP + ABPEquation (7)where: ASP is the projected luminous side area (length) viewed at angle ABP is the projected luminous bottom area (length) viewed at angle These are
47、a projections are calculated at “side“ hori-zontal positions for given vertical angle “. The total projected side area is used with the side candela value measured at angle to get the average side luminance of the luminaire. For a luminaire end (viewing the width dimension) use the formula: total pr
48、ojected luminous end area = ASP + ABPEquation (8)where: ASP is the projected luminous end area (width) viewed at angle ABP is the projected luminous bottom area Figure 1 - Luminous area and projected luminous area illustrated for flat lens or open bottom circular luminaires. ( Illuminating Engineeri
49、ng Society of North America)Figure 2 - Bottom luminous area, side luminous area, and two projected luminous areas illustrated for drop lens circular luminaires. ( Illuminating Engineering Society of North America)4IES LM-37-16Figure 3 - Bottom luminous area and projected luminous area illustrated for flat lens or open bottom square or rectangular luminaires. ( Illuminating Engineering Society of North America)Figure 4 - Bottom luminous area and four projected luminous areas illustrated for drop lens square or rectangular luminair
