ES 6 Light Level Studies Planning Meeting January 16, Lisa Brasche Iowa State University

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1 ES 6 Light Level Studies Planning Meeting January 16, 2003 Lisa Brasche Iowa State University lbrasche@cnde.iastate.edu

2 Light Level Survey Results Subdued lighting exists in the inspection booth at four of the seven responses (one organization provided quantification of <1fc) One of seven has computer monitor in the inspection booth with <1fc at 15 inches UV sources used in addition to standard 100W handheld included: UVA hand 250 BL from Dr. Hoenle (2) UV-Technik, bulb 200W halogen Labino (2) Höhler Karl Deutsch UV-Grossflächen.Leuchte Spectroline HID lights at 20K microwatts Lumatec SuperLite with liquid light cable Olympus - Model ALS-UV6250 with UV light guide Spectronics AP-800 Ultrawand (8W, integrally filtered, long wave UV fluorescent tube)

3 Filters Light Level Survey Results Glass filters from several manufacturers, transparency nm Filter for UV-B and UV-C (Filter BL 400nm with frame) OEM & Kopp Spectronics 2F191 Kopp No. 71 Kopp No. 41

4 Light Level Survey Results Light meters used: Ardrox DLM-1000 with UVA (4) Spectromax Spectronics Spectroline DSE-100X Digital Radiometer (2) with: DIX-365 sensor for UV measurement (1) DIX-555 sensor for white light measurement Gigahertz Optik Optometer P 9720 (1) Spectroline Model DSE-2000A (radiometer/photometer system)

5 Light Level Survey Results Five of seven responders measure visible light at same distance as UV light (15 ) No industry standard for acceptable level for a given distance Ambient light levels are measured at the inspection surface in five of seven responses and inside the inspection booth in one of seven. One of five responders uses a special fixture to guarantee the same distance with each measurement. Ambient light levels are measured at the part surface in field inspections by four of seven. One of seven does not consider outside of the booth inspections to be calibrated inspections and two did not respond

6 Light Level Survey Results Time for dark adaptation ranged from one to 5 minutes At least one minute Minutes depending on the person 3-5 minutes (5 minutes as required in to. 33b-1-1) 1-3 min. from shop to darkroom and 5 min when entering from sunlight 2 minutes Minimum one minute

7 AMS 2647.B Inspect parts in a booth or darkened area where ambient white light at the inspection surface(s) does not exceed 20 lx (2 foot-candles). Use light meter for measurement of white light Blacklight should be turned on for at least 15 minutes before beginning inspection Before beginning inspection, the individual shall wait at least one minute to adapt to darkness vision. Photochromic lenses or darkened lenses shall not be worn during inspection When possible, place blacklight within 150 to 300 mm (6 to 12 inches) of part surface during the inspection.

8 AMS 2647.B Blacklight: All UV light sources used to inspect parts shall be checked for output using a UV lightmeter on a daily basis or as necessary to ensure the following output is provided: Standard 100 watt blacklights shall provide not less than 1000 mw/cm2 at 380 mm (15 inches). Turn on blacklights not less than 15 minutes prior to verifying the intensity of the blacklight Blacklight borescopes, flexible scopes and UV liquid light guides that are used to inspect parts shall provide not less than 1000 µw/cm2 at 3.8 cm (1.5 inches) UV pen lights that are used to inspect, shall provide not less than 1000 µw/cm2 at 1.27 cm (1/2 inch) All other UV light sources that are used to inspect parts shall provide not less than 1000 µw/cm2 at the inspection surface of the part Self-filtered blacklight bulbs shall not be used unless specified by OEM s procedures If the filter glass is dirty, scratched, damaged, or poor fitting so that white light escapes, the condition shall be corrected or the unit replaced. CAUTION: Unfiltered ultraviolet radiation is hazardous. Blacklight bulbs shall have suitable filters to eliminate short and medium wavelength ultraviolet radiation.

9 ES 6 - Light Level Studies Use DSE-100X or DLM meters for light level measurements ES 6a Correlation of light level and brightness Use spotmeter to document relationship between UV level and crack brightness Function of crack size Distance from surface Real part geometry (curvature) Penetrant type White light level Developer dwell time

10 ES 6 - Light Level Studies ES 6b - Dark adaptation study Review other literature (medical, human factors, etc.) for recommended parameters. Perform POD study with interrupted light/dark exposure and compare to POD for recommended dark exposure.

11 Other needs? Comparison of filters? Light Level Studies