Transcription
Information Circular 9074Underground Coal MineLighting Handbook(In Two Parts) 2. ApplicationCompiled by W. H. LewisUNITED STATES DEPARTMENT OF THE INTERIORDonald Paul Hodel, SecretaryBUREAU OF MINESRobert C. Horton, Director
Library of Congress Cataloging-in-Publication DataMain entry under title:Underground coal mine lighting handbook.(Information circularlunited States Department of theInterior, Bureau of Mines; 9074)Bibliographies.Supt. of Docs. no.: I 28.27:Contents: v. 1. Background-v.2. Application.1. Mine lighting. 2. Coal mines and mining.I. Lewis, W. H. (William H.) 11. Series: Information circular (United States. Bureauof Mines); 9074.TN309.U47
PagePage1Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .2Chapter 1.-Light measuring techniques and2instrumentation . . . . . . . . . . . . . . . . . . . . . . .Portable photoelectric photometers . . . . . . . . .2Photocell characteristics . . . . . . . . . . . . . . .2Color correction . . . . . . . . . . . . . . . . . . . . .2Cosine correction . . . . . . . . . . . . . . . . . . . .3Sensitivity . . . . . . . . . . . . . . . . . . . . . . . .3Purkinje shift . . . . . . . . . . . . . . . . . . . . . .3Calibration . . . . . . . . . . . . . . . . . . . . . . . .3Photometer zeroing . . . . . . . . . . . . . . . . . .4Temperature and humidity effects . . . . . . . .4Contamination . . . . . . . . . . . . . . . . . . . . .4Stray light . . . . . . . . . . . . . . . . . . . . . . . .44Go, no-go coal mine photometer . . . . . . . . . . .Making illuminance measurements . . . . . . . . .45Making luminance measurements . . . . . . . . . .Making reflectance measurements . . . . . . . . .56Other measuring instruments . . . . . . . . . . . .Chapter 2.-Illumination regulations for under7ground coal mine environments and equipment . .The primary illumination standard andits basis . . . . . . . . . . . . . . . . . . . . . . . . . . .7Applying the illumination standard in themine environment . . . . . . . . . . . . . . . . . . . .7Additional standards for implementing faceillumination systems . . . . . . . . . . . . . . . . . .8Electrical requirements . . . . . . . . . . . . . . .8Antiflicker requirements . . . . . . . . . . . . . . 10Requirements concerning luminaires in ablasting zone . . . . . . . . . . . . . . . . . . . . . . 11Antiglarerequirements . . . . . . . . . . . . . . . 11MSHA STE program . . . . . . . . . . . . . . . . . . .11Value of STE program to mine operators andsome important limitations . . . . . . . . . . . . . 12STE application process and informationrequirements . . . . . . . . . . . . . . . . . . . . . . . 12Application form . . . . . . . . . . . . . . . . . . . . 12Machine layout drawing . . . . . . . . . . . . . . . 13One-line diagram . . . . . . . . . . . . . . . . . . . . 13Electrical schematic . . . . . . . . . . . . . . . . . . 13Light measurement data . . . . . . . . . . . . . . . 14Short-circuit calculations(longwall-stationary systems) . . . . . . . . . . 16Specifying optional equipment on STEapplications . . . . . . . . . . . . . . . . . . . . . . . . 16MSHA review of STE applications . . . . . . . . . 16Modification of STE-approved designs . . . . . . . 17Requirements for installation of lightingsystems . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Inspection of face lighting systems . . . . . . . . . 18Procedures for STE-approved systems . . . . . . 19Procedures for non-STE-approved systems . . 19Instruments and techniques for takinglight measurements . . . . . . . . . . . . . . . . . 19Additional requirements to improvevisibility underground . . . . . . . . . . . . . . . 20Chapter 3.-Lamps and ballasts . . . . . . . . . . . .Criteria for lamp performancecharacterization . . . . . . . . . . . . . . . . . . . . .Incandescent lamps . . . . . . . . . . . . . . . . . . . .Principle of operation . . . . . . . . . . . . . . . . .Life-efficacy relationship . . . . . . . . . . . . . . .Krypton-filled . . . . . . . . . . . . . . . . . . . . . .Tungsten-halogen . . . . . . . . . . . . . . . . . . .Fluorescent lamps and ballasts . . . . . . . . . . . .Principle of operation . . . . . . . . . . . . . . . . .Types . . . . . . . . . . . . . . . . . . . . . . . . . . . .Performance characteristics . . . . . . . . . . . .Fluorescent ballasts . . . . . . . . . . . . . . . . . .Ballast heating and related designconsiderations . . . . . . . . . . . . . . . . . . . . .High intensity discharge lamps. high-pressuresodium and mercury vapor . . . . . . . . . . . .Mercury vapor lamps . . . . . . . . . . . . . . . . . .Functional description . . . . . . . . . . . . . . . .Efficacy-lumen output . . . . . . . . . . . . . . . .Spectral energy distribution . . . . . . . . . . . .Lamp life . . . . . . . . . . . . . . . . . . . . . . . . .Effect of voltage variation . . . . . . . . . . . . . .Flicker . . . . . . . . . . . . . . . . . . . . . . . . . . .Ballasts . . . . .'. . . . . . . . . . . . . . . . . . . . .High-pressure sodium lamps . . . . . . . . . . . . .Principle of operation . . . . . . . . . . . . . . . . .Efficacy-lumen output . . . . . . . . . . . . . . . .Lumen depreciation . . . . . . . . . . . . . . . . .‘.Spectral energy distribution . . . . . . . . . . . .Lamp life . . . . . . . . . . . . . . . . . . . . . . . . .Effect of voltage variation . . . . . . . . . . . . . .Flicker . . . . . . . . . . . . . . . . . . . . . . . . . . .Ballasts . . . . . . . . . . . . . . . . . . . . . . . . . .Chapter 4.-Available mine lighting hardware . .Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .Hardware evaluation . . . . . . . . . . . . . . . . . . .Ruggedness and durability . . . . . . . . . . . . .Electrical reliability . . . . . . . . . . . . . . . . . .System servicing . . . . . . . . . . . . . . . . . . . .Illumination performance . . . . . . . . . . . . . .Miscellaneous . . . . . . . . . . . . . . . . . . . . . .Chapter 5.-Design and evaluation of coal mineillumination systems . . . . . . . . . . . . . . . . . . .Recommended design methodology . . . . . . . . .Information collection and assembly . . . . . . .Generate illumination system conceptalternatives . . . . . . . . . . . . . . . . . . . . . . .Illumination system concept evaluationconsiderations . . . . . . . . . . . . . . . . . . . . .Install lighting system . . . . . . . . . . . . . . . .Evaluate installed system . . . . . . . . . . . . . .Design methods and considerations . . . . . . . . .Durability . . . . . . . . . . . . . . . . . . . . . . . . .Component mounting methods andconsiderations . . . . . . . . . . . . . . . . . . . . .Methods to evaluate and reduce discomfortglare . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
CONTENTS- ContinuedPageChapter 6.-Installing and maintaining minelighting systems . . . . . . . . . . . . . . . . . . . . . . .Guidelines for system installation . . . . . . . . . .Preparation . . . . . . . . . . . . . . . . . . . . . . . .Mounting luminaires . . . . . . . . . . . . . . . . .Housing and connecting power conditioningequipment . . . . . . . . . . . . . . . . . . . . . . . .Cable installation . . . . . . . . . . . . . . . . . . .Gland protection . . . . . . . . . . . . . . . . . . . .Guidelines for system maintenance . . . . . . . . .Maintenance approach . . . . . . . . . . . . . . . .Exchange maintenance . . . . . . . . . . . . . . . .Scheduled and preventive maintenance . . . .Record keeping . . . . . . . . . . . . . . . . . . . . .Maintenance training . . . . . . . . . . . . . . . . .58585859596061616162626363PageRecommendations for minimizing lampmortality and lamp replacement costs . . . . . .Assessing lamp costs . . . . . . . . . . . . . . . . .Assessing increased lamp mortality inmine applications . . . . . . . . . . . . . . . . . . .Factors causing increased mortality oflamps in mine application . . . . . . . . . . . . .Measures to improve lamp life and lampservicing suggestions . . . . . . . . . . . . . . . . . .Group relamping . . . . . . . . . . . . . . . . . . . . .Appendix A.-Federal specifications for lightingface equipment and coal mine,longwalls . . . . . .Appendix B.-Specifications of available arealuminaires and power-conditioning systemsapproved for application in underground coalmine working places . . . . . . . . . . . . . . . . . . . .ILLUSTRATIONS1. Function of color correcting filter on response of photocells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 . Diffusing cover for cosine correction on photometers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 . Photocell orientation for making illumination measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 . Photocell fitted with adapter for luminance measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5, Reflected-incident light comparison method for measuring reflectivity . . . . . . . . . . . . . . . . . . . . . . . .6 . Luminance standard comparison technique for measuring reflectivity . . . . . . . . . . . . . . . . . . . . . . . . .7. Resistance-grounded neutral grounding circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 . Longwall power distribution circuit for breaker setting calculation . . . . . . . . . . . . . . . . . . . . . . . . . . .9 . Intrinsically safe pilot circuit with explosion-proof connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10. System layout drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11. One-line diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12. Electrical schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13. "Unfolded-box" diagram for presenting light measurement data . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14. Significance of interreflections when taking light measurements in mine simulators . . . . . . . . . . . . . .15. STE system approval plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16. Procedure for using go, no-go photometer when clearance permits holding the meter 5 ft from entry walls . .17 . Procedure for using go, no-go photometer when clearance does not permit holding meter 5 ft from entry walls . .18. Lamp mortality curve example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19. Common shapes of mine lamps and letter designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 . Construction of typical incandescent lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 . Spectral energy distribution of tungsten a t 3,000 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 . Effect of voltage variation on the operating characteristics of incandescent filament lamps . . . . . . . . . .23 . Construction of typical fluorescent lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 . Specular energy distribution curves for common fluorescent phosphor mixtures . . . . . . . . . . . . . . . . . .25 . Change in light output of a fluorescent lamp a s a function of ambient temperature . . . . . . . . . . . . . . .26 . Change in light output and wattage of a fluorescent lamp a s a function of line voltage . . . . . . . . . . . . .27 . Dual-lamp, series-sequence-type. rapid-start fluorescent ballast circuit . . . . . . . . . . . . . . . . . . . . . . . .28 . Typical mercury vapor lamp construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 . Spectral energy distribution of a typical clear mercury vapor lamp . . . . . . . . . . . . . . . . . . . . . . . . . . .30 . Mercury vapor lamp ballasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 . Typical high-pressure sodium lamp construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 . Spectral energy distribution of typical high-pressure sodium lamp . . . . . . . . . . . . . . . . . . . . . . . . . . .33 . Lamp characteristics that must be accommodated in high-pressure sodium lamp ballast design . . . . . . .34 . Trapezoid specification for high-pressure sodium lamp ballast performance defined by lamp characteristics and upper-lower wattage limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 . Important aspects of ballast characteri sticcurves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 . High-pressure sodium lamp ballasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 . Important cage design distinctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 . Tubing versus clamp-style packing glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PageEffect of gland orientation on cable routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Alternative wiring configurations for dc application of incandescent headlamp pairs . . . . . . . . . . . . . . .Example photometric profile diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical mine simulator used to establish STE data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Methods of luminaire protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example of damage to lighting hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example luminaire mountings that improve durability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example power supply mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example of principal lines of sight for a roof bolting machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Disability glare diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Apparent contrast versus visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glare shields used to reduce disability glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Disability glare versus luminaire position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Luminaire orientation change to reduce disability glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Luminaire selection and placement to reduce disability glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Luminaire orientation change to reduce discomfort glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Discomfort glare versus luminaire brightness and area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Example of retrofitted glare diffusers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Quick-release luminaire bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Recommended gland guard designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Effects of vibration and shock on lamp filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Shadowgraph to test fluorescent lamp filament continuity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Laboratory measured mortality curves for lamp types used in coal mining applications . . . . . . . . . . . . .Joy Manufacturing Co . model 500131-33 and 500131-35 luminaires . . . . . . . . . . . . . . . . . . . . . . . . . .M d u n k i n Corp . model 100164 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M d u n k i n Corp . model 100/30H, 100115, and 10016 luminaires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M d u n k i n Corp . model 400-A and 4 0 0 3 luminaires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mine Safety Appliances Co . model LX2401 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mining Controls Inc . model 21322 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mining Controls Inc . tungsten-halogen luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .National Mine Service Co . model 5401-0012, 5401-01 11, 5401-0004, and 5401-0103 luminaires . . . . . . .National Mine Service Co. model 5401-0202 and 5401-0293 luminaires . . . . . . . . . . . . . . . . . . . . . . . .National Mine Service Co . model 5402-0995 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ocenco Inc . model 30M and 1513M luminaires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ocenco Inc . model 16M luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ocenco Inc . model AR-150 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Service Machine Co . model D513 luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .West Virginia Armature Co . model 18400-24 and 18400-18 luminaires . . . . . . . . . . . . . . . . . . . . . . . .West Virginia Armature Co . model 14812D luminaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Installation and wiring.schematics for intrinsically safe fluorescent systems on a typical coal mine longwallface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B.18 . Installation and wiring schematics for explosion-proof fluorescent systems on a typical coal mine longwallface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 .40 .41 .42 .43.44 .45.46 .47 .48 .49 .50.51.52 .53.54 .55.56 .57 .58.59.60 .61.B-1.B-2 .B-3.B-4.B-5.B-6.B-7.B-8 .B-9.B-10 .B-11.B-12.B-13.B-14 .B-15 .B-16 .B-17 .7.8.9.B-1.B.2 .B-3 .B.4 .Trailing cable maximum allowable instantaneous circuit breaker settings . . . . . . . . . . . . . . . . . . . . . . 9Cable resistance based on conductor size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Comparison of field modifications of STE's and STE extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Headlight equivalence listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Categories of available lighting hardware and identification of U.S. manufacturers . . . . . . . . . . . . . . . 36Summary of illumination performance differences dependent on lamp types utilized in a luminaire . . . . 44Common mechanisms that mechanically damage luminaires on mobile coal mine face machines . . . . . . 47Example illumination system concept evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Scheduled maintenance checklist for mine illumination systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Joy Manufacturing Co. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77Joy Manufacturing Co . luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77McJunkin Corp . system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78McJunkin Corp . luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
-15.B-16.Mine Safety Appliance system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mine Safety Appliance luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mining Controls Inc. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mining Controls Inc. luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .National Mine Services Co. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .National Mine Services Co. luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ocenco Inc. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ocenco Inc. luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Service Machine Co. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Service Machine Co. luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .West Virginia Armature Co. system alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .West Virginia Armature Co. luminaire specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .798080808282848486868687UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORTA"CCISOFfcamperedegree Celsiuscycle per seconddegree Fahrenheitfootcandlefootlambertfootsquare footfoot per secondhourhour per dayinchsquare inchkelvinfLftft2ft/shh/dinin2KkW1blm/WmAminnm c tssrVWW/ftYrkilowattpoundlumen per anvoltwattwatt per footyear ISELECTED CONVERSION FACTORSAbbreviationUnit of measurec/in2candle per square inchc/m2candle per square meterfcfLfootcandlefootlambertlxluxTo convert tocandle per square meterfootlamberticandleper square inchifootlambertluxcandle per square inchicandleper square meterfootcandleMultiply by0.000645,002211,550.291910.76452.43.426.092903
UNDERGROUND COAL MINE LIGHTING HANDBOOK(In Two Parts)2. ApplicationCompiled by W.H. Lewis1ABSTRACTThis Bureau of Mines report and its companion report (Information Circular9073) have been prepared as a complete reference on underground coal minelighting. This report discusses system design criteria and procedures, data andspecifications to aid in selection of suitable mine lighting hardware, and guidelines for system installation and maintenance. Topics include light measuringtechniques and instruments, illumination regulations for underground coal mineenvironments and equipment, lamps and ballasts, available mine lightinghardware, design and evaluation of coal mine illumination systems, and installation and maintenance of a mine lighting system.'Electrical engineer, Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA.
INTRODUCTIONThis Bureau of Mines report and its companion report,Information Circular 9073, have been prepared as a complete reference on underground coal mine lighting. Thereports are intended to assist those persons who design,install, andlor maintain mine lighting systems in makingappropriate decisions.This report discusses system design criteria and procedures, data and specifications to aid in selection of suitable mine lighting hardware, and guidelines for systeminstallation and maintenance. Topics include light measuring techniques and instruments, illumination regulations for underground coal mine environments and equipment, lamps and ballasts, available mine lighting hardware, design and evaluation of coal mine illuminationsystems, and installation and maintenance of a mine lighting system. The report provides information to insure anunderstanding of the numerous, complex, and interrelatedfactors that must be considered to design and implement amine lighting system that will satisfy human needs forgood vision and comfort.CHAPTER 1.-LIGHTThe design of good lighting systems for undergroundcoal mines is no easy task because of the unique environment and work procedures encountered in coal mines. Theprimary objective of these reports is, therefore, to identifythe major problems encountered in this lighting application and to provide guidance in the solution of theseproblems. If they are carefully designed and implemented,lighting systems provide mine workers improved visibility and contribute to improved safety, productivity, andmorale. Properly designed lighting systems can prove tobe a very cost-effective investment for the mine operator.This report was prepared by BCR National Laboratory(BCRNL), Monroeville, PA, under Bureau of Mines contract 50113063. The following contributed significantly tothe production of the report: J . Yingling and K. Whitehead, BCRNL; A. Szpak, ADS Engineering and Design,Inc.; and personnel of the CIE Mine Lighting Committee,the Illuminating Research Institute, and Applied ScienceAssociates, Inc.MEASURING TECHNIQUES AND INSTRUMENTATIONLighting, from the viewpoint of engineering data andcomputations, is discussed in Bureau of Mines Information Circular (IC) 9073. Instruments are, however, requiredto evaluate lighting systems and components. The field oflight measurement is called photometry, and the instruments used to measure lighting are called photometers.Many types of photometers are available to measurelight energy and related quantities, including illumination,luminance, luininous intensity, luminous flux, contrast,color, and visibility. The discussion in this report is limited to photometers used to measure illumination, E, andluminance, L, from which other quantities, such as reflectivity and luminous intensity, may be computed.The photometer is one of the most important tools forillumination system design and evaluation. Specific usesfor underground mine illumination system measurementsareVerification of compliance with illumination and luminance specifications in the regulations;Evaluation of illumination system design options;Calculation of reflectance of mine and mine simulatorsurfaces;Checking light distribution;Checking illumination depreciation over time; andEvaluation of discomfort and disability glare.Before taking measurements with a photometer, caremust be taken to insure that a luminaire or illuminationsystem is in the proper condition to satisfy the purpose ofthe measurements. An adequate warmup period shouldbe allowed for fluorescent, sodium vapor, and mercuryvapor luminaires. For instance, the light output of sometypes of fluorescent luminaires can be twice as great asinitial levels after a 30-min warmup period. The light output of some luminaires (especially incandescent) can varywidely with deviations in line voltage from nominal. Dirtyluminaires, obstructions, or deviations in luminaire mountings and orientations from specifications can significantlyalter illumination levels.PORTABLE PHOTOELECTRIC PHOTOMETERSThe portable photoelectric photometer consists of aphotocell that receives light and converts it into a n electrical signal that is conditioned through an electrical circuitand is displayed on a visual meter. The meter reading isproportional to the light energy level received by thephotocell.Even the more simple and durable photometers aredelicate instruments that can give highly erroneous resultswhen improperly used or calibrated. Proper instruction inthe use and calibration of photometers cannot be overstressed. Many factors can cause significant errors in themeasurements in the very low light levels typical of underground coal mines. Photometers are available in a varietyof models ranging from the low-cost,handheld units, whichare very convenient but have limited accuracy and range,to more expensive, and more accurate but less portableunits.The following major factors affecting the accuracy ofphotometers should be understood and considered beforepurchasing and using a unit.Photocell CharacteristicsPhotocells used in portable photometers have beenimproved significantly in the past few years. New designphotometers that utilize silicon photocell technology havedistinct advantages when compared with selenium photocell photometers. Silicon photocells are more stable andexhibit a more uniform (linear) response in output with achange in light level. Selenium photocells are more proneto change in calibration with time and also can exhibit amemory (hysteresis) effect when measured light levels varysignificantly. When exposed to illumination, the output ofphotocells decreases over a period of time because of fatigue.Therefore, the meter should be exposed to the light levelbeing measured for as long an adaptation period as necessary; i.e., until the meter reading stabilizes.
Color CorrectionSensitivityThe response of the human eye (spectral luminousefficiency) for photopic (daylight) vision is shown in figure1, along with the response curve for a typical uncorrectedselenium photocell. Note that the response of the cell differs significantly from that of the
lighting. This report discusses system design criteria and procedures, data and specifications to aid in selection of suitable mine lighting hardware, and guide- lines for system installation and maintenance. Topics include light measuring techniques and instru
