4. APTA SS-PS-004-99, Rev. 1 Standard for Low-Location Exit Path ...

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Annex D (informative) Passive LLEPM field test and criteria D.1 Technical considerations There are three variables that affect the visibility of the LLEPM signs: a) Illuminance charging levels provided by ambient light b) Amount of time that the sign is exposed to light c) Type of activating light source 4.19 APTA SS-PS-004-99, Rev. 1 Edited 4-1-04 An illumination level of 5 foot-candles (fc) has been shown to provide adequate charging light for LLEPM material to meet the criterion of 7.5 mcd/m 2 in rail passenger cars, 1.5 hours after normal power is removed. Adequate light for HPPL charging to meet the 7.5 mcd/m 2 criterion is generally available at all locations, except directly under the seats or if there are overhangs or other obstructions that block light from reaching the LLEPM. Another variable is the available HPPL charging time. To meet the 7.5 mcd/m 2 criterion, the adequate charging time at 5 fc would be at least 30 minutes from dark storage to departure. Most HPPL materials reach saturation at about 30 minutes. The standard time for the test procedure is set at 60 minutes to make certain that all samples have reached saturation and to make the results less sensitive to small errors in the timing of measurements. While 5 fc provides adequate charging light with cool-white fluorescent lighting, warm-white fluorescent or incandescent lights are less effective at charging. If warm-white fluorescent or incandescent fixtures are used, the minimum actual charging level may need to be increased 20 to 50 per cent respectively to ensure that the charging level and time for LLEPM products is adequate. As a general rule, if the value of the ambient illuminance level (fc) at the location where the product is installed, multiplied by the number of minutes of exposure to a light source (natural or artificial), exceeds 150, then the charge is adequate. In addition, some samples of HPPL material may be more efficient than others at absorbing an ambient light charge, thus actual charging times may differ. However, It should also be noted that for the same charging time (but in locations where the illuminance on the surface of the HPPL signs is higher for the same amount of time; e.g., 20 fc for 60 minutes), the sign luminance may be only be increased by 25%. Finally, proper placement must avoid damage from cleaning. Volume VI - Passenger System

D.2 Verification of compliance options 4.20 APTA SS-PS-004-99, Rev. 1 Edited 4-1-04 Compliance with this standard is ultimately the responsibility of the railroad. One of the two options described below shall be followed by the railroad and HPPL material manufacturer/supplier to verify that the LLEPM products, as installed in their final configuration and location, meet the minimum luminance criterion of 7.5 mcd/m 2 , after 1.5 hours from the removal of normal and emergency lighting, D.2.1 Illuminance To confirm that the HPPL material is installed in locations that receive adequate charging, illuminance measurements shall be taken on the surface of the material as installed in all locations (including any protective layer or cover), with an illuminance meter. Two suggested instruments that can be used to conduct the measurements are the Minolta T-10 or the Extech 401036. (Others are available from Hagner Instruments, Gigahertz Optik, and LMT-Berlin). All offer serial data outputs for logging measurements directly to a computer. The charging source shall consist of the actual light fixtures used in the car. If light diffusers are used on the fluorescent light fixtures, the measurements shall be made with the light diffusers in place. The minimum illuminance value measured directly on the surface of the LLEPM material shall be 5 fc. D.2.2 Luminance It is not expected that railroads will themselves conduct luminance measurements of the HPPL material used for LLEPM products installed in their cars due to the technical complexity of measuring the luminance performance. However, this option may be used by the LLEPM manufacturer/supplier, in cooperation with the railroad, to confirm that HPPL materials, as installed in their final configuration and location, meet the minimum 7.5 mcd/m 2 , 1.5 hours after normal and emergency power is removed (instead of the option described in D.2.1). When a car to be tested arrives: a) When a railcar to be tested arrives, immediately place strips of gaffer’s tape or other opaque tape (duct tape cannot be used because it transmits too much light) on each installed LLEPM strip. These tape strips must prevent any ambient light from charging the signage. b) Wait at least 48 hours to begin testing (see Items D.2.2.l and D.2.2.m for correction factors). c) Prior to testing, the temperature of the railcar interior must be stabilized in the normal operating range, 77 +/- 5°F. (Cars stored outside in cold weather are likely to show seriously degraded performance, if they are tested before being warmed to normal temperatures). Volume VI - Passenger System

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Page 5 and 6: Contents 4.4 APTA SS-PS-004-99, Rev

Page 7 and 8: 2. References 4.6 APTA SS-PS-004-99



Page 13 and 14: 5.3 LLEPM exit door markings 4.12 A

Page 15 and 16: Annex A (informative) Bibliography

Page 17 and 18: Annex B (informative) Passive LLEPM

Page 19: C.2 Underwriters’ Laboratories (U


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